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Happy Valentine's Day!

2/13/2017

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Author: Maddie Van Beek

Tomorrow is Valentine's Day! Today, we are going to perform some experiments on some Valentine's candy and make a DIY crystal Valentine gift for someone!


History of Valentine's Day
Valentine's Day started as a feast to honor Saint Valentinus. Watch the video below for a history of Valentine's Day! ​
Valentine's Day may also be associated with the ancient Roman Festival of Lupercalia, in which young men and women were paired up. Since the 14th century Valentine's Day has evolved to be a holiday that celebrates love. By the 18th century, people started expressing love through small gifts and cards called valentines.  

Candy Hearts Experiment
In this experiment, you will determine whether candy hearts react with baking soda or vinegar. You are looking for a chemical reaction.
Picture
A chemical reaction...
* Occurs between two or more atoms or molecules
* Causes bonds between atoms to break
* Forms new bonds
* Creates new molecules


Basically, two substances interact to create a new form or substance.


Read this link for more information on chemical reactions:
Chemical Reactions
Now that you know a little bit about chemical reactions, let’s move on to our experiment!


YOU WILL NEED:
* Candy hearts (Sweethearts brand)
* Vinegar
* Baking soda
* Water
* Two bowls
* Glass
* Measuring cups


Here's what to do!
1. Place a few candy hearts in each bowl.
2. Add 1 cup water and 1 tablespoon baking soda to your glass. Stir until the baking soda dissolves.
3. Pour 1/2 cup vinegar into the first bowl. Observe what happens.
4. Pour 1/2 cup baking soda water into the second bowl. Observe what happens.
5. Which addition caused a chemical reaction, the baking soda water or the vinegar? Why do you think this is? Write down your thoughts.

So, you noticed that your candy hearts react with the baking soda water and not with the vinegar. What does that tell you? What else reacts with baking soda? Think back to other science experiments you may have done in the past. For more info, take a look at this blog we posted back in 2014: http://www.discoveryexpresskids.com/blog/use-vinegar-and-baking-soda-to-blow-up-a-balloon​

Now that you know candy hearts react with baking soda, you are going to figure out WHY they react with baking soda. What ingredient in a candy heart might be causing this reaction? Take a look at the ingredients on the back of your candy hearts package.

Candy hearts contain these ingredients:
* Sugar
* Corn syrup
* Dextrose
* Glycerine
* Artificial and natural flavors
* Gelatin
* Vegetable gums (tragacanth, xanthan, arabic)
* Citric acid
* Artificial colors (red 3, yellow 5, yellow 6, red 40, blue 1)
​

You are going to test each of these ingredients separately to see which one is causing the chemical reaction.


YOU WILL NEED:
* Muffin tin (or several small bowls)
* Baking soda
* Sugar
* Corn Syrup
* Lemon juice
* Glycerine
* Water
* Food coloring
Picture
Here's what to do!
1. Put one teaspoon of sugar in one muffin cup and label it “sugar.” Put one teaspoon of corn syrup in the second muffin cup and label it “corn syrup.” Continue this process with the lemon juice, glycerine, and food coloring.
2. Add 1/4 cup water to each ingredient. In the sixth muffin cup, add 1/4 cup plain water.
3. Stir each ingredient until it dissolves in the water.
4. Now you get to start testing!
5. Add a spoonful of baking soda to each muffin cup. What happens? Which one reacts?


You should have noticed that the muffin cup with the lemon juice produced fizzing bubbles! There’s your chemical reaction! Remember, lemon juice contains citric acid. The citric acid in the candy hearts is what caused them to react with the baking soda water in your first experiment. Baking soda is a base. When acids and bases are mixed together, they react. That reaction produces carbon dioxide gas. You saw that gas in the form of those fizzy bubbles.

Another acid-base reaction that you have probably seen before is between baking soda and vinegar. Mix them together for more fizzy fun!
​

Now that you've performed some experiments, you get to use your crafty skills to make a valentine decoration!


Crystal Heart
You are actually going to create a crystal decorative heart by first boiling borax and then letting it crystallize.
Picture
Borax crystals
What is borax?

Borax (short for boric acid) is a white mineral that is often used for cleaning. In its natural form, it is actually a crystal. Large borax deposits are found in California and Turkey, but borax is also commonly found in Tibet, Romania, and Bolivia.
​
Borax crystal can be white or clear. 

To learn more about borax, click the link below.

What is borax?
What is crystallization?

We've seen crystallization in action when we created crystal egg geodes or when we made our own rock candy.

You are going to create a borax solution by adding borax to boiling water. When you add borax to water, it will dissolve. If you keep adding borax, eventually there will be a point that no more will dissolve. At this point, your borax solution is saturated. If you keep adding borax, it will just sink to the bottom and the solution becomes supersaturated. This means that the liquid in the solution contains more solute (borax) than it can hold. A supersaturated solution is unstable, so it produces a precipitate. A precipitate is a solid that is produced from a solution. In this case, the precipitate is your borax crystal.


YOU WILL NEED:
* Borax (Find it in the same area as the detergents in your local grocery store)
* Food coloring
* Pipe cleaner
* Water
* Saucepan
* Stove


Here's what to do! 

​1. Boil water in a saucepan on the stove. (Make sure you ask an adult for help)
2. While you’re waiting for the water to boil, create a heart (or whatever shape you want) out of your pipe cleaner. When you’re finished creating your shape, place it in a glass jar.
3. Once the water boils, add borax. Stir until the borax dissolves. Continue adding borax until it will no longer dissolve. You’ll know your solution is supersaturated when the borax just sinks to the bottom. Remove the solution from the stove and add food coloring (optional).
4. Pour the borax solution into the glass jar. Make sure your pipe cleaner shape is completely submerged.
5. Leave the jar undisturbed for 24 hours.
6. Check back the next day. What happened?! Dump the borax solution down the drain and remove your crystal heart.

Image and video credits
Yo Bo, 2013. Animated history of Valentine's Day. Uploaded from YouTube on 2/13/2017. https://youtu.be/sHmVFJ3QlPw

Evan-Amos, 2011. Image uploaded from Wikimedia Commons on 2/13/2017. 
https://upload.wikimedia.org/wikipedia/commons/thumb/9/9b/Necco-Candy-SweetHearts.jpg/1024px-Necco-Candy-SweetHearts.jpg File in the Public Domain. 

Dulyan, A., 2005. Borax crystals. Image uploaded from Wikimedia Commons on 2/13/2017. 
https://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Borax_crystals.jpg/800px-Borax_crystals.jpg File in the Public Domain. ​
​
References
​https://en.wikipedia.org/wiki/Valentine's_Day
​https://en.wikipedia.org/wiki/Borax
​http://www.kiddyhouse.com/Valentines/
http://inspirationlaboratories.com/valentine-candy-science-candy-heart-reactions/
http://inspirationlaboratories.com/valentine-candy-science-candy-heart-ingredients-experiment/
http://fun-a-day.com/candy-heart-experiments-valentines-day/
http://chemistry.about.com/od/valentinesdaychemistry/a/Borax-Crystal-Heart.htm
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Layers of liquid density: Create a Rainbow in a Jar

1/23/2017

3 Comments

 
Author: Maddie Van Beek

Normally we associate rain with the spring season, but with the recent warm winter temperatures in Fargo, we've had some January rain. No matter the season, the cool thing about rainy days is that they are often accompanied by beautiful rainbows! 
Picture
This is a double rainbow, seen in Wrangell-St. Elias National Park in Alaska. (Photo credit: Eric Rolph)
Did you know that rainbows are actually caused by refraction? If you want to learn more, check out our blog! 
​
If you want to learn more about rainbows, click the button below:
Rainbow Fun Facts
Another cool phenomenon that is seen more often in winter is a sun dog! Similar to a rainbow, sun dogs are also caused by refraction. Light is refracted from ice crystals and creates a halo around the sun. The sun dogs appear to the left or right of the sun, although they most often occur in pairs. So while you might not see too many rainbows in the winter, you can always look for sun dogs!
Picture
These sun dogs were seen in Fargo, North Dakota!
Now that you know more about rainbows, we're going to make our own... IN A JAR!
Picture
Of course, you can make density towers in graduated cylinders, too!
How will we do that?! Today, you will be experimenting with liquid density. The varying densities of different liquids will allow you to layer them without them mixing, thus, creating a “rainbow in a jar.” 


Before we try this fun experiment, you need to know a little bit about density. 


The density of a given liquid is determined by mass or how closely the molecules in that liquid are packed.


Density does not only exist in liquids, but in all states of matter. The density of a material is its mass per unit volume. What does this mean? 


The density equation shows us that density is mass (weight) divided by volume (the amount of space that a substance occupies):
Picture
Basically, this equation tells us that density is the amount of matter in a given space. 

In relation to our project, the density of a liquid is determined by how many molecules of that substance fit into a set volume. 


Think about it. Let’s say you put five gummy bears into a Ziploc bag for your little brother and 20 gummy bears into the same size Ziploc bag for yourself. Whose bag of gummy bears is more dense? 


A liquid with less molecules or smaller molecules is less dense than a liquid that has more molecules or larger molecules.
​

Which figure is more dense? 
Picture
If a liquid weighs more than than another liquid with equal volume, the heavier liquid has a higher density. The higher density liquid will sink below lower density liquids. Let’s check out an example that you are probably very familiar with. 


Demonstration: Pour 1/4 cup oil and 1/4 cup water into a glass. Which liquid sinks to the bottom (aka, which liquid is more dense?)


What does this tell you about these two liquids? 


This leads us into our activity for the day!


So you know that water is more dense than oil. Now, let’s try this out with a bunch of liquids. By using many liquids of varying densities, you can make a liquid rainbow in a jar!




YOU WILL NEED:

  • Mason jar
  • 1/4 measuring cup
  • Food coloring (several different colors)
  • Water
  • Turkey baster or some form of dropper
  • Olive oil
  • Honey
  • Corn Syrup
  • Dish soap
  • Rubbing Alcohol



Here’s what to do!

  1. The first liquid that you will add to your jar is the honey. Use the 1/4 measuring cup to measure out 1/4 cup of honey, and then pour it into the jar. Make sure you pour it straight into the middle of the jar--be careful not to get it on the sides!
  2. Rinse out the measuring cup. You will need to do this after each liquid is added. 
  3. After the honey settles into an even layer, add the corn syrup (again, make sure to dump it in the middle without hitting the sides!). If you want your rainbow to be more colorful, mix in a few drops of food coloring with the corn syrup before you add it to the jar. 
  4. Next, measure and add the dish soap. 
  5. After the dish soap settles, measure and add the water. Again, add a few drops of food coloring to the water before adding it to the jar to make your rainbow more colorful! Use a different color than you did for the corn syrup so you can tell the difference. 
  6. Next, you will measure and add the the olive oil. 
  7. Last, you will measure and add the rubbing alcohol. You can use food coloring to color this liquid, as well! But wait! You will need to use the turkey baster or dropper for this one! Add the liquid in very carefully, so it doesn’t mix with the other layers. 
  8. You’re done! You have your very own rainbow in a jar! 



Follow-up Questions: 

  • What enabled you to make a liquid rainbow? 
  • Explain why these liquids didn’t just mix together. 
  • Were you surprised by your results? Why or why not? 
  • Draw your liquid rainbow and label each layer to record which liquids are more or less dense. 



Extension: 

Try this out with different liquids! See if you can discover densities of other common liquids in your home.


If you need a visual, check out this video of the experiment you just tried! They use even more liquids than we did, so if you need more ideas, this video is a great resource! 
Image and video credits, in order of appearance

​Rolph, E., 2007. Double-alaskan-rainbow. File uploaded from Wikimedia Commons on 1/22/2017. 
https://upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Double-alaskan-rainbow.jpg/1280px-Double-alaskan-rainbow.jpg File used in accordance with Creative Commons Attribution-Share Alike 2.5 Generic License. Image was not changed. 

Gopherboy6956, 2009. Fargo Sundogs 2 18 09. File uploaded from Wikimedia Commons on 1/22/2017. ​
https://upload.wikimedia.org/wikipedia/commons/thumb/8/88/Fargo_Sundogs_2_18_09.jpg/800px-Fargo_Sundogs_2_18_09.jpg Image in the Public Domain. 

Kelvinsong, 2013. Artsy density column. File uploaded from Wikimedia Commons on 1/22/2017. 
https://en.wikipedia.org/wiki/Density#/media/File:Artsy_density_column.png ​File used in accordance with the CC Attribution-Share Alike 3.0 Unported. Image was not changed.

​Density example created by Maddie Van Beek.

The Sci-Guys, 2013. The Sci-Guys: Science at Home - SE1 - EP5: 12 Layer Liquid Density Tower. Video uploaded from YouTube on 1/22/2017. 
https://www.youtube.com/watch?v=4EMUsPJtCoc&feature=youtu.be
3 Comments

Sweet Solutions: Make your own rock candy

1/15/2017

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Author: Maddie Van Beek

Today, you are going to learn about supersaturated solutions and crystals! We touched on these concepts last week when we learned how to make Egg Geodes. This time, you will be making your own rock candy! ​
Picture
A solution is a group of molecules that are mixed together and evenly distributed (homogenous). This is a little different from a mixture, which is unevenly distributed (heterogenous). 

​
Check out this link to learn more about the difference between solutions and mixtures:
Mixtures and Solutions: What's the difference?
In order to make rock candy, you will be creating a sugar-water solution.
Sugar science and candy-making
Follow-up questions:

  • Where is sugar found?
  • What is sugar made of? 
  • What kinds of foods do you find sugar in? 



When you dissolve sugar into water, you are creating a solution. Your sugar is the solute, and your water is the solvent. ​
Picture
This is a saline solution created with salt and water. The water is the solvent and the salt is the solute.
As the sugar dissolves, the sucrose molecules separate from one another because of their attraction to the water molecules. But, only a certain amount of a solid can be dissolved into a liquid. When you reach a point that no more sugar will dissolve in the water, you know that your solution is saturated. If you try to keep adding sugar, it will just sink to the bottom. At this point, the sugar will stop dissolving and start crystallizing. 
Picture
When a solution is supersaturated, it becomes unstable. The prefix “super” means that it contains more solute than the liquid can hold. Thus, a precipitate is created. A precipitate is a solid deposited from a solution. In this case, the precipitate is the sugar crystals. ​

​When you are creating rock candy, the supersaturated solution creates a sugar crystal precipitate. The other process that is going on is evaporation. As the water evaporates, your sugar-water solution becomes more and more saturated with sugar, thus creating sugar precipitate, aka ROCK CANDY!!!
Picture
YOU WILL NEED:

  • Adult assistance/supervision
  • Sugar
  • Water
  • Glass jar
  • Stove
  • Pan
  • 1/4 measuring cup
  • Spoon
  • String or wooden skewer
  • Clothespin
  • Food dye (optional)
  • Patience (necessary) 



Here’s what to do!

1. Ask an adult for help with this project--it requires the use of a hot stove and boiling water. 

2. Place the wooden skewer inside the glass jar and clip the clothespin horizontally so that the wooden skewer is suspended about 1 inch from the bottom of the jar. If you are using string, tie one end of the string around a pencil and the other end of the string around a washer or similar weighted object. This will help hold your string in place later on. Just like the skewer, suspend the string about 1 inch from the bottom of the jar. 

3. Put the string or skewer aside for now. 

4. Pour 1 cup of water into a pan and bring it to boil on the stove. 

5. Pour 1/4 cup of sugar into the boiling water and stir it with a spoon until it dissolves completely. 

6. Continue adding 1/4 cup of sugar and stirring until you can no longer get the sugar to dissolve. Make sure you continue until NO MORE will dissolve! 

7. When you reach that point, remove the sugar water from the stove and let it cool for at least 20 minutes. 

8. Carefully dip your string or skewer into the sugar water and then lay it aside to dry. Make sure it dries completely. Doing this will help jumpstart your sugar crystal formation, as it creates “seed crystals.” The seed crystals on the string or skewer will draw the sugar precipitate towards them as the water evaporates. 

9. At this point, you can add and stir in several drops of food dye if you would like your rock candy to be colored. 

10. Have an adult help you carefully pour the sugar solution into the glass jar until it is about 1 inch from the top. 

11. Place your skewer or string back into the glass, and make sure it is hanging straight down the middle without touching the sides. 

12. Patience! You will now need to wait for 3-7 days. Check back daily to see the progress in sugar crystal growth! Keep a log to track the growth. 

13. Enjoy!
Image and video credits (in order of appearance)
Amos, E., 2012. Rock-candy-sticks. File uploaded from Wikimedia Commons on 1/15/2017. 
https://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Rock-Candy-Sticks.jpg/1024px-Rock-Candy-Sticks.jpg File used in accordance with the CC Attribution-Share Alike 3.0 Unported. Image was not changed. 

Chris 73, 2012. SaltInWaterSolutionLiquid. File uploaded from Wikimedia Commons on 1/15/2017.
https://upload.wikimedia.org/wikipedia/commons/thumb/8/89/SaltInWaterSolutionLiquid.jpg/320px-SaltInWaterSolutionLiquid.jpg 
​File used in accordance with the CC Attribution-Share Alike 3.0 Unported. Image was not changed. 

Amos, E., 2012. Rock-Candy-Closeup. File uploaded from Wikimedia Commons on 1/15/2017.

https://upload.wikimedia.org/wikipedia/commons/thumb/9/98/Rock-Candy-Closeup.jpg/800px-Rock-Candy-Closeup.jpg ​File used in accordance with the CC Attribution-Share Alike 3.0 Unported. Image was not changed. ​

References:
​https://en.wikipedia.org/wiki/Supersaturation
https://www.exploratorium.edu/cooking/candy/rock-pop.html
https://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2014-2015/candymaking.html
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Happy New Year!

1/1/2017

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Author: Maddie Van Beek

Happy New Year! It’s 2017! Today we are going to do some fun activities to celebrate. But first, check out this New Year’s Science Quiz to see what you know! It’s okay if you don’t know all the answers—there are explanations at the end so you can start the year off right by learning something new!
New Year Science Quiz
Now that you’ve taken a quick science quiz, it’s time to set some science goals for your year! Have you ever heard of a New Year’s Resolution? Every year, thousands of people around the country make a resolution (goal) to make some sort of positive change in their lives. Most of the time, (88% of the time according to the link below), people fail at keeping their New Year’s resolutions. Why is that?! Too often, people don’t make their goals concrete or reachable, so the resolution quickly seems unattainable. You need to actually train your brain, your prefrontal cortex, specifically, by creating habits in order to achieve your goals. Who knew?!
​
Read the links below to find out why resolutions fail and how to keep yours!
Why do resolutions fail?
How will you keep your New Year's resolution?
Write your goal down, decorate it, and paste it inside your science notebook as a reminder.

Now that you’ve set a science goal for the year, let’s move on to our New Year’s activities!

Fireworks in a Glass

In this activity, you will use oil and water along with food coloring to create a mixture that looks like fireworks in a glass. The science behind this activity is that oil and water DO NOT MIX. Why don’t they mix? They do not mix because water is polar (it has an uneven distribution of electrons in its molecules) and oil is not (it has a very even distribution of electrons in its molecules). Things that are polar usually don't mix well with things that are not polar, like oil (they are not attracted to each other), while things that are polar--like sugar--usually dissolve well in water (the water molecules are attracted to the sugar molecules). If you need a little more help, check out our earlier blog about solubility:

http://discoveryexpress.weebly.com/blog/what-is-solubility

Watch the video below for a more in-depth explanation of why oil and water don’t mix:
YOU WILL NEED
* Clear glass
* Food coloring
* Vegetable oil
* Water
* Shallow bowl
* Fork

Here’s what to do!
1. Pour a cup of vegetable oil in the shallow bowl.
2. Sprinkle about 12 drops of food coloring in the oil. Use as many different colors as you want! These will be the colors of your “fireworks.”
Picture
Food coloring drops in oil. Water and oil do not mix!
3. Use a fork to lightly stir the food coloring in with the oil. Don't stir too much! Just break up any big blobs of food coloring. The food coloring is water-based, so it won’t fully mix in with the oil, but it will break up into smaller blobs when you stir. 
4. Fill a glass about ¾ full of warm water.
5. Slowly pour the oil/food coloring mixture into the warm water. What happens?
6. The oil stays on top! Remember, oil and water will not mix. The oil is less dense than water, so it floats on top. The food coloring is water-based, so it’s denser than the oil. Eventually, the food coloring blobs will slowly sink through the layer of oil and reach the water. When this happens, the color expands and looks like little colorful explosions!
Picture
Here you can see the water on the bottom and the layer of oil on the top. The orange food coloring drops are slowly sinking through the oil.
Picture
When the food coloring drops sink through the oil... FIREWORKS! The water-based food coloring blob expands once it meets the water.
Confetti Eruption

In this activity, you will see baking soda and vinegar react, much like when we did exploding glow in the dark art (http://discoveryexpress.weebly.com/blog/exploding-glow-in-the-dark-art).

Baking soda (a base) and vinegar (an acid) create an acid-base reaction. When this reaction occurs, carbon dioxide gas is released in the form of foamy bubbles. For a full explanation of why these two substances react together, check out this link:

http://scienceline.ucsb.edu/getkey.php?key=4147

YOU WILL NEED
* Baking soda
* Vinegar
* Plastic party cups (or any glass)
* Confetti or glitter
* Food coloring (optional)
* Bowl
* Turkey baster or eye dropper


Here’s what to do!
1. Fill a small bowl with about two cups of baking soda. The amount doesn’t really matter, but two cups is enough for plenty of foamy fun!
2. Add a few spoonfuls of confetti or glitter to your baking soda.
3. Add a tablespoon of water to your baking soda and mix it in. Continue to do this until you have a dough-like consistency. This more evenly distributes the confetti and makes the mixture easier to scoop into the glasses.
4. Place the party glasses in a baking pan to contain the mess. This will make cleanup easier.
5. Scoop about ¼ cup of the mixture into each party glass.
6. Pour a cup of vinegar into a separate glass and add a few drops of food coloring if you want your eruptions to be colored!
7. Use the turkey baster or eye dropper to suck in the vinegar.
8. Squeeze the vinegar into the party glass. TADA! You should see a colorful, glittery eruption! Repeat as often as you want to create more foamy fun. As the foam fizzles out, just add more baking soda or more vinegar.
Picture
Picture
I used sprinkles, which was fun because it made my eruptions even more colorful!
Image and Video Credits:
Pollard, J., 2013. "Why don't oil and water mix?" Ted-Ed. Uploaded from YouTube on 1/1/2017.
https://www.youtube.com/watch?v=h5yIJXdItgo
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Christmas Science: Fizzing Gingerbread Men, Peppermint Oobleck, and Dissolving Candy Canes!

12/5/2016

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Author: Maddie Van Beek

Christmas is coming up quick! What do you think of when you hear the word Christmas? You might think of family, baking, presents, cookies, candy canes, etc. Write down all the things you can think of!


Let’s use some of the holiday cheer for some fun Christmas science experiments! Today, we are going to create fizzing gingerbread men (or other christmas shapes), play with peppermint SLIME, and see how long it takes to dissolve a candy cane. Let’s get started!


Fizzing Gingerbread Men
Picture
In this experiment, you are going to create Christmas shapes out of a baking soda paste. Once the shapes dry, you’ll put them in a pan of vinegar and watch them FIZZ! Why will this happen? Baking soda, or sodium bicarbonate, is an example of a base. Other bases you might see in the real world are often in the form of cleaners, such as bleach or ammonia. Can you think of any others?
Vinegar is an example of an acid. You might already know that many fruits have acid in them. What else is acidic?​

So we know that baking soda is a base and vinegar is an acid... why do we see fizz when they meet? When acids and bases are mixed together, a REACTION occurs. That reaction produces carbon dioxide gas. The gas appears in the form of bubbles! Now that you know the science behind the reaction, let’s get started!


YOU WILL NEED:
* Baking Soda
* Christmas Cookie Cutters
* Water
* Vinegar
* Pan
* Bowl


Here’s what to do!
1. Dump 2 cups of baking soda into a bowl.
2. Add water a little bit at a time and stir until you have a thick baking soda paste.
3. If you would like to, add a few drops food coloring and stir into the paste.
4. Set the cookie cutter shapes that you would like to use on a pan.
5. Press the baking soda paste into the cookie cutter shapes.
6. Let dry undisturbed until the paste has hardened (a few hours).
7. Carefully pop your shapes out of the cookie cutters.
8. Fill the pan with vinegar and place your shapes in the pan. Watch the reaction happen! How long do you think it will take your shapes to fully dissolve? Make a prediction!
9. If you add more vinegar, does it help the shapes dissolve faster? Try it out!


Peppermint Oobleck
We’ve made Oobleck or SLIME in the past, but this time we’re going to make it Christmassy! What is Oobleck? When you mix cornflour and water, you get a non-newtonian fluid. A non-newtonian fluid behaves sometimes like a liquid and sometimes like a solid. It will behave like a liquid until you apply sudden pressure or stress, and then it will act like a solid.

For example, you could run across a pool of oobleck, but if you stood still, you would sink!

Watch this video to see non-newtonian fluid in action!
Ok, now let’s get started!


YOU WILL NEED:
* Cornstarch
* Water
* Peppermint Essence
* Red food coloring
* Bowl
* Measuring cups


Here’s what to do!
1. Dump 1 cup of cornstarch into a bowl.
2. Measure 1/4 cup of water.
3. Add a few drops of red food coloring into the water. Next, add 1 teaspoon of peppermint essence.
4. Dump the red peppermint water into the cornstarch and stir. What happens?
5. You should be able to pick up the goo and form it into a ball, like a solid! When you stop moving your hands, it should run through your fingers like a liquid! If the goo is too thick, add a little more water. If it’s too runny and can’t be formed into a ball, add a little more cornstarch.
6. Have fun!


Dissolving Candy Canes
Picture
In this experiment, you are going to see how long it takes a candy cane to dissolve in warm water, cold water, and vinegar! What does it mean to dissolve? A solution is
formed when a solid becomes part of a liquid. Example: When you stir Kool-Aid mix (the solute/solid) into water (the solvent/liquid), Kool-Aid (a solution) is formed. We are going to see whether different solvents (warm water, cold water, vinegar) affect how fast a candy cane will dissolve!


PREDICT: Which candy cane will dissolve fastest? Slowest? Why?


YOU WILL NEED:
* Candy canes
* 3 Glasses
* Warm water
* Cold water
* Vinegar


Here’s what to do!
1. Select 3 glasses of the same size.
2. Put 1 cup of warm water into the first cup, 1 cup of cold water in the second cup, and 1 cup of vinegar into the third cup.
3. Place an unwrapped candy cane into each cup.
4. Check back every five minutes and see how much of each candy cane has dissolved. Record your observations.
5. After an hour, record your results! Were you surprised? What other liquids could you test out? Try using different temperatures of water to see if hotter or colder water makes a difference.




References:

http://sciencelearn.org.nz/Science-Stories/Strange-Liquids/Non-Newtonian-fluids https://en.wikipedia.org/wiki/Non-Newtonian_fluid

Image and video credits, in order of appearance
The Discovery Slow Down, 2013. Non-newtonian liquid in slow motion. https://youtu.be/G1Op_1yG6lQ


Alcinoe, 2005. Crispy gingerbread cookies. File uploaded from Wikimedia Commons on 12/4/2016. https://upload.wikimedia.org/wikipedia/commons/7/79/CrispyGingerbreadCookies.jpg Image in the Public Domain.


Amos, E., 2011. Candy-Cane-Classic. File uploaded from Wikimedia Commons on 12/4/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/d/de/Candy-Cane-Classic.jpg/800px-Candy-Cane-Classic.jpg Image in the Public Domain.
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Cranberry Science for Thanksgiving!

11/14/2016

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Author: Maddie Van Beek

​Thanksgiving is coming up! One of the most popular Thanksgiving staples are cranberries. Cranberries are small, red berries that grow on a shrub. They’re usually sweetened into a sauce or jam, often for Christmas or Thanksgiving.
Picture
At the holidays, you might see whole cranberries, jellied cranberries, or cranberry sauce. How can we use cranberries for science? Let’s find out!

Cranberry Reactions

Watch cranberry juice react with baking soda and lemon juice!

There are two reasons that cranberries are going to react in our experiment today. One, cranberries are acidic. As you might know, when acids and bases meet, a chemical reaction takes place. You’ve seen this happen when you mix baking soda (a base) and vinegar (an acid). What happens? Lots of fizzing and bubbles! Remember, those bubbles are releasing carbon dioxide gas as a product of the reaction. The second reason that you’ll see a special reaction from cranberries is because of their pigment, anthocyanin. Anthocyanin is what makes cranberries their deep red color. When the acidity changes in the juice, anthocyanin reacts by changing color! Today, you’re going to mix cranberry juice with baking soda and lemon juice to see how these ingredients react with each other.
Picture
YOU WILL NEED:
* Cranberry sauce, juice, or whole cranberries
* Baking soda
* Lemon juice
* Glass or container
* Measuring spoons


1. If you’re using cranberry sauce, make sure it’s thawed out and in liquid form. If you’re using whole cranberries, mash them up and add a little hot water to get a good amount of juice.
2. Pour the cranberry juice into a glass. You should have at least one cup of juice.
3. Predict what will happen when you add a spoonful of baking soda to the glass of cranberry juice.
4. Add the baking soda and observe what happens. Record your observations.
5. Predict what will happen when you add lemon juice to the cranberry juice.
6. Add two tablespoons of lemon juice and observe the reaction! What happened?
7. Record your findings.
8. Extension: Add different amounts of baking soda or lemon juice. Does that make a difference? Can you get the color to change even more? What happens if you add baking soda and lemon juice at the same time?


Cranberry Building

In this activity, you will use cranberries to build the tallest structure possible!


YOU WILL NEED:
* Fresh, whole cranberries
* Toothpicks


Here’s what to do!
1. Unwrap your cranberries.
2. Connect two cranberries with a toothpick.
3. Continue building and connecting cranberries to build whatever structure you want. See how tall you can make your building before it tips over!
4. Test out the strength of your structure by setting an object on top. See how much your structure will hold!
5. Challenge: Try rationing yourself to only 20 toothpicks. Using those 20 toothpicks, what shape will create the strongest structure? Try a few different structures and test which one is the strongest!


Cranberry Sauce Recipe
Picture
Here’s a great cranberry sauce recipe that you can use for the holidays! Impress your family by helping out with this traditional treat!


YOU WILL NEED:
* 12 ounce bag of cranberries
* Sugar
* Orange zest
* Pepper
* Water
* Salt
* Pan
* Stove

Here's what to do!
1. Empty your cranberries into a saucepan.
2. Transfer 1/2 cup of the cranberries into a small bowl. 
3. Add 1 cup sugar, 1 strip orange zest, and 2 tablespoons water to the saucepan. 
4. Stir over low heat until the cranberries soften and the sugar dissolves.
5. Increase to medium heat cook until cranberries burst. 
6. Reduce to low heat and add the 1/2 cup of reserved cranberries. 
7. Add sugar, salt, and pepper to taste. 
8. Let cool to room temperature before serving.  

Recipe from: 
http://www.foodnetwork.com/recipes/food-network-kitchens/perfect-cranberry-sauce-recipe.html

Image credits, in order of appearance:
Weller, K., 2005. Cranberry bog. Image uploaded from Wikimedia Commons on 11/13/2016. 
https://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Cranberry_bog.jpg/1024px-Cranberry_bog.jpg
File in the Public Domain. 

Cjboffoli, 2010. Cranberries20101210. Image uploaded from Wikimedia Commons on 11/13/2016. 
https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Cranberries20101210.jpg/1024px-Cranberries20101210.jpg ​File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license. No changes were made.

Veganbaking.net, 2008. Cranberry sauce. Image uploaded from Wikimedia Commons on 11/13/2016. 
https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Cranberry_Sauce_%283617909597%29.jpg/800px-Cranberry_Sauce_%283617909597%29.jpg 
File used in accordance with the Creative Commons Attribution 2.0 Generic license. No changes were made.

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Halloween Science: Candy Chromatography

10/9/2016

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Picture
Author: Maddie Van Beek

Halloween is only a few weeks away! That means it's time for some spooky fun with Halloween science activities! 


1. Use your colorful candy to try out candy chromatography! 


What exactly is chromatography? 


Chroma means color and graphein means to write. 


There are a few different kinds of chromatography, but today you are going to be dealing with paper chromatography. When you use paper chromatography, you can separate different inks or dyes into their individual components. For example, a black marker actually has many different colors of dye to create black ink.

​Watch the video below to watch how paper chromatography can be used to separate black ink into its individual colors:
You can use this same idea to separate the dyes of your favorite candies! 


YOU WILL NEED
  • M&Ms or Skittles
  • Coffee filter paper
  • A tall glass 
  • Water 
  • Table salt 
  • Pencil
  • Scissors
  • Ruler 
  • 6 toothpicks 
  • Aluminum foil 
  • 2 liter bottle with cap


Check out our blog about candy chromatography here for instructions:
Candy Chromatography
2. Create your own glowing beverages! 


Did you know that tonic water glows under a black light? The reason that it does this is because of one special ingredient: quinine. 


Why is quinine fluorescent? Read the link below to find out! ​
Why is quinine fluorescent?
Now that you know about quinine, do you know what a black light is? Why is a black light any different from a regular light? They might appear the same as any other light bulb, but they function very differently. Black lights actually produce ultraviolet light. When you turn a black light on, it causes white things to glow in the dark. 


Read about black lights in the link below to find out how they work: ​
How do black lights work?
YOU WILL NEED
  • Tonic water
  • Ice cube trays
  • Sprite or 7-up
  • A black light

​
Here’s what to do! 


The instructions for this activity are very simple. Make ice cubes out of tonic water and then put them in any light colored drink such as 7-up or Sprite. Turn on a black light, turn off the lights, and watch your beverages glow an eery blue!

​
3. Make pumpkin slime!



The slime that you will be creating is a non-newtonian fluid. Newtonian fluids behave as you would expect a liquid to behave. For example, when you hit water, it gives way. You can easily put your hand through it without much resistance. Non-newtonian fluids sometimes act like a solid and sometimes act like a liquid. When you hit a non-newtonian fluid, it resists the impact. How can that be? 


Watch this video to see people experiment with non-newtonian fluid. They even try to bike across it! You’ll be amazed at its power to resist stress. 
YOU WILL NEED:
  • One pumpkin
  • Cornstarch 
  • Mixing bowl
  • Spoon
  • Cookie sheet or pan
  • Food coloring (optional: your pumpkin will already color your slime an orangey tint)
Check out our blog from a few weeks ago to learn more about non-newtonian fluids and create your own pumpkin slime:
Create Your Own Pumpkin Slime
References:
https://sciencebob.com/free-halloween-science-ideas/

http://www.scientificamerican.com/article/shining-science-explore-glow-in-the-dark-water/
​
http://science.howstuffworks.com/innovation/everyday-innovations/black-light.htm

Image and video credits, in order of appearance: 

Amos, E., 2010. Plain-M&Ms-Pile. File uploaded from Wikimedia Commons on 10/9/2016.
https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/Plain-M%26Ms-Pile.jpg/800px-Plain-M%26Ms-Pile.jpg Image released into the Public Domain. 

Pauller, N., 2014. Paper chromatography - Chemistry experiment with Mr Pauller. Video uploaded from YouTube on 10/9/2016. ​https://youtu.be/ZCzgQXGz9Tg

Hard Science, 2013. Biking across a pool of corn starch - Hard science. Video uploaded from YouTube on 10/9/2016. ​https://www.youtube.com/watch?v=BleCJJAKkgw&feature=youtu.be
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The Science of Meat Tenderizer: How do enzymes work? 

9/18/2016

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Author: Maddie Van Beek

The name “meat tenderizer” seems pretty self-explanatory, but have you ever wondered how meat tenderizer works? Doesn’t the tenderness of the meat just depend on the quality or how long it’s cooked? Obviously a filet mignon is more tender than a sirloin, right? It’s not quite that simple. You can use meat tenderizer to make tougher cuts of meat softer, and this is actually a chemical process!

You CAN tenderize meat through force, using a tool that looks something like this: ​
Picture
This method of meat tenderizing breaks the physical bonds of the meat, through force, not through any chemical change. 

But there are many other effective methods of meat tenderizing that involve using a store-bought meat tenderizer, other substances such as baking soda or yogurt, or marinating the meat using acidic substances such as tomato juice or vinegar. 

Here are the ingredients listed for a popular basic meat tenderizer made by McCormick:

Ingredients: Salt, dextrose, bromelain (tenderizer), and calcium silicate (added to make free flowing). 

You can see that the main ingredient is Bromelain. Bromelain is made from pineapple and is just one kind of proteolytic enzyme that is commonly used in meat tenderizers. A proteolytic enzyme (aka protease) is a protein that digests other proteins by breaking them down into smaller pieces.


Other proteolytic enzymes include Papain, which is made from papaya, and Ficin, which is made from figs.

You might be wondering, what do enzymes even do? Here is a basic illustration of how enzymes work:  
Picture
This illustration shows the substrates binding with the enzyme in the active site. This binding is called the enzyme-substrate complex. The bonds in the substrates weaken and form a new shape, called the product.
Click HERE for more information about enzymes!

Are enzymes only used in meat tenderizer? Of course not! 

PREDICT: How do you think enzymes work in YOUR body? 

Check this video out to find out more about what enzymes do for YOU! 
​Whats the difference between using an enzymatic meat tenderizer and marinating meat in vinegar, tomato or lemon juice? 

They both break down bonds in the meat, but enzymatic meat tenderizers use enzymes to break down the connective tissue in meats while acidic substances use acid to break down that same tissue. 

PREDICT: Which meat tenderizer will be most effective? 

YOU WILL NEED:
  • One large steak
  • Knife
  • McCormick (or other brand) Meat Tenderizer
  • Meat Tenderizing tool
  • Baking soda
  • Vinegar
  • Yogurt
  • Six small tupperware containers
  • Masking tape
  • Pen



HERE’S WHAT TO DO: 
  1. Make sure you have an adult to help you cut the steak.
  2. Wash your hands and prepare a clean cooking space. Place the steak on a clean surface. 
  3. Cut the steak into six equal pieces. 
  4. Place each piece into a separate container. 
  5. Sprinkle a teaspoon of baking soda onto the first piece. Rub the baking soda into the meat. Label the container using the masking tape and a pen and place in the refrigerator. Make sure you label each container right away so you can keep the pieces of meat straight. 
  6. Sprinkle meat tenderizer onto the second piece of meat, label the container, and place in the refrigerator. 
  7. Cover the third piece of meat in yogurt, label, and refrigerate. 
  8. Douse the fourth piece of meat in vinegar, label, and refrigerate. 
  9. Tenderize the fifth piece of meat by hitting it with the meat tenderizer tool for two minutes, label, and refrigerate. 
  10. Do not do anything to the sixth piece of meat. Label the container and place in the refrigerator. 
  11. Leave all pieces of meat in the refrigerator for 24 hours. 
  12. Remember to clean up and wash your hands!!! It’s very important to wash your hands after handling raw meat. 
  13. Make your prediction! Which piece of meat will be the tenderest? 
  14. After 24 hours, have an adult help you cook the meat. Make sure each piece of meat is cooked in the same way for the same amount of time. 
  15. In order to keep the pieces organized after cooking, you could use separate plates and label each with the masking tape and pen.
  16. After each piece is done, it’s time to sample! 
  17. Grab a few friends to help you sample the meat and have them each rate the pieces from toughest to tenderest. 
  18. Create a visual representation to report your findings. 


EXTENSION:

Have you ever heard that Coca-Cola can dissolve a steak? Try it out and see if it works! Start by making predictions: How long will it take? Why is the Coca-Cola able to break down a whole steak? Is the Coca-Cola breaking the steak down through acid or enzymes? 

Check the steak and record your observations every 8 hours for the first 24 hours and then every 24 hours after that. What changes is the steak going through? Did the steak ever fully dissolve? How long did it take? 


References:

http://www.slideshare.net/mixhiela/enzymes-activity-in-tenderizing-meat

http://homecooking.about.com/od/specificdishe1/a/marinadescience.htm

http://www.slideshare.net/mzsanders/how-enzymes-work

http://www.cookingscienceguy.com/pages/wp-content/uploads/2012/07/The-Many-Lives-and-Uses-of-Baking-Soda.pdf

https://en.wikipedia.org/wiki/Enzyme

Image and video credits, in order of appearance:

dumbledad, 2008. Flatten pork steaks-01. Uploaded from Wikimedia Commons on 9/18/2016.
https://upload.wikimedia.org/wikipedia/commons/thumb/0/0f/Flatten_pork_steaks-01.jpg/1024px-Flatten_pork_steaks-01.jpg File used in accordance with the Creative Commons Attribution 2.0 Generic license. No changes were made. 

Shafee, T., 2015. Hexokinase induced fit. Uploaded from Wikimedia Commons on 9/18/2016. 
https://upload.wikimedia.org/wikipedia/commons/thumb/f/f5/Hexokinase_induced_fit.svg/800px-Hexokinase_induced_fit.svg.png File used in accordance with the Creative Commons Attribution-Share Alike 4.0 International license. No changes were made. 

Ricochet Science, 2015. How Enzymes Work. Uploaded from YouTube on 9/18/2016. 
https://youtu.be/UVeoXYJlBtI
2 Comments

Use yeast to blow up a balloon! 

9/11/2016

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Author: Maddie Van Beek 

You may have heard of yeast, but today you will actually learn what this substance is and what it does.

​Have you ever seen a little square packet labeled yeast in your cupboard at home or on a shelf at the grocery store and wondered it was used for? 

Inside the packet, you’ll see a substance that looks something like this:
Picture
Granulated dried yeast
Picture
Some yeast is packaged like the picture above. Rather than packets of dried yeast granules, this is compressed fresh yeast.
Pretty boring, right? Why would these little brown granules called yeast be so important for making bread? 

Did you know that yeast is not only crucial to bread rising, it is actually ALIVE?!

The scientific name for this tiny little organism is Saccharomyces cerevisiae, but they should just call it, “sugar-eater.” Yeast feeds on the sugar in the bread dough and converts it into carbon dioxide. The carbon dioxide creates little bubbles in the dough, which is what causes the bread to rise and creates a nice spongy texture rather than a hard flatbread. Your PB&J sandwiches would have never been the same without the discovery of yeast! 

This could not happen without yeast:
Here is a close-up of what yeast organisms look like:
Picture
Yeast under a microscope
How does yeast work?
CHECK FOR UNDERSTANDING:
  • What kind of organism is yeast? 
  • Where might you find yeast?
  • What does yeast do? (What is its job?)
  • What is yeast used for? Think of a few different examples. 


Learn more about bread-related science and the research that is going into yeast today!

Remember when we blew up a bag with baking soda and vinegar? Today, we are going to try something similar with yeast!

Check out this video for a demonstration of what you will do!
CHECK FOR UNDERSTANDING:
  • Based on your experience last week, what do you think is happening as the yeast blows up the balloon? 
  • How is the balloon being blown up?
  • What is the yeast doing to produce gas?
  • What kind of gas is being produced? 



Now that you've seen a demonstration of what yeast can do, try it out yourself! 

YOU WILL NEED:

  • Baker’s yeast
  • Warm water
  • Water bottle
  • Balloon
  • Sugar
  • Funnel



HERE’S WHAT TO DO:

  1. First, you need to stretch out your balloon. Blow it up a few times to loosen it up. 
  2. Next, measure one cup of very warm water.
  3. Stir in one packet of yeast and two tablespoons of sugar. Keep stirring until the mixture is dissolved.
  4. Place the funnel at the mouth of the water bottle, and pour the sugar-water-yeast substance into it. 
  5. Stretch the mouth of the balloon over the mouth of the water bottle.
  6. Wait, and record your observations. This may take a while, so you might want to check back every 15-20 minutes. 
  7. What does the sugar-water-yeast substance look like at first? What happens over time? What happens to the balloon? How long does this take? 



Extension 1:

Test out how different water temperatures might affect the yeast! 




YOU WILL NEED:

  • Thermometer
  • Ruler/tape measure



PREDICT: How might temperature affect the yeast? 




HERE’S WHAT TO DO:

  1. Follow the instructions above, except use a different temperature of water. Try using very hot water, lukewarm water, cold water, etc. You will need a thermometer in order to accurately track how temperature affects the production of carbon dioxide. 
  2. Use a ruler to measure how large the balloon gets. Measure from the mouth of the water bottle to the top of the balloon each time.  
  3. Repeat the experiment as many times as you would like with different temperatures of water and record your observations each time. 
  4. Create a graph to demonstrate the relationship between water temperature and carbon dioxide production. Your X-axis would be temperature and your Y-axis would be inches grown. For Excel instructions, check out our recent blog on heart health. (You would be creating a graph of inches  grown as a function of water temperature). 



Extension 2:

Test out how different amounts of sugar might affect the yeast!

Does more sugar equal more carbon dioxide? Try it out! 

PREDICT: How might the amount of sugar affect the yeast? Will more sugar make the balloon grow bigger? 


HERE'S WHAT TO DO: 

  1. Follow the instructions in the original experiment, except use a different amount of sugar. Try using one tablespoon, 1/2 teaspoon, 1/4 cup, etc. 
  2. Use the ruler to measure how large the balloon gets. 
  3. Create a graph to demonstrate the relationship between the amount of sugar used and carbon dioxide production. Your X-axis would be the amount of sugar used and your Y-axis would be inches grown. For Excel instructions, check out our recent blog on heart health. (You would be creating a graph of inches grown as a function of the amount of sugar used). 



References: 

http://phys.org/news/2013-11-bread-beer-national-yeast-cultures.html

http://www.scientificamerican.com/article/watch-yeast-live-breathe/

https://www.exploratorium.edu/cooking/bread/activity-yeast.html

http://science.howstuffworks.com/life/fungi/yeast-info.htm

http://en.wikipedia.org/wiki/Yeast#Baking
Image and video credits, in order of appearance
​
Hellahulla, 2007. Compressed fresh yeast. Uploaded from Wikimedia Commons on 9/11/2016.
https://upload.wikimedia.org/wikipedia/commons/thumb/e/e9/Compressed_fresh_yeast_-_1.jpg/1024px-Compressed_fresh_yeast_-_1.jpg File used under GNU Free Documentation License. No changes were made. 

Ranveig, 2005. Dry yeast. 
​https://upload.wikimedia.org/wikipedia/commons/thumb/9/90/Dry_yeast.jpg/800px-Dry_yeast.jpg File in the Public Domain. No changes were made. 

Reynaud, 2012. Bread rising (Timelapse). Uploaded from YouTube on 9/11/2016. 
​https://youtu.be/0z8hrRXQuHY

Masur, 2009. S cerevisiae under DIC microscopy. Uploaded from Wikimedia Commons on 9/11/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/d/d9/S_cerevisiae_under_DIC_microscopy.jpg/800px-S_cerevisiae_under_DIC_microscopy.jpg File in the Public Domain. No changes were made. 

Timstar Laboratory Suppliers, 2013. Demonstration of keystage 3 biology experiment - Blow up a balloon with yeast. Uploaded from YouTube on 9/11/2016. ​https://youtu.be/wTmcUvQhU-o


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Experimenting with Eggs: Acid-Base Reactions and Osmosis

8/15/2016

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Author: Maddie Van Beek


What do you think of when you hear the word reaction?


Explosions? 


A rash? 


A response based on a previous situation or event? 


None of these thoughts are wrong, but today, we are talking about acid-base reactions. Check out the link below to define exactly what an acid-base reaction is.
Learn more about acid-base properties
FOLLOW UP QUESTIONS
  1. What is an acid-base reaction? 
  2. Why do acids and bases react and what happens when acids and bases react with one another? 
  3. What compound is created from an acid-base reaction? 
  4. Use a Venn Diagram to compare and contrast acids and bases. 


Learn more about Acid-Base reactions in this Crash Course video by Hank Green! 
Let’s check out our own acid-base reaction!

Make sure you do this experiment in the kitchen (or other easily cleanable area) or outside, if weather permits. 



YOU WILL NEED:
  • Baking soda
  • Vinegar
  • Ziplock bag
  • One square of paper towel
  • Measuring spoons
  • Measuring cups



Predict: What do you think will happen when you mix baking soda and vinegar in a sealed plastic bag? 



YOU WILL DO
  1. Double check that your Ziplock bag has no holes. To test this out, fill it up with water and zip it up. If you see a leak, get a new bag. 
  2. Create a “time-release” packet of baking soda. 
    1. Place your paper towel on a flat surface. 
    2. Measure 1.5 Tablespoons of baking soda and dump it in the center of the paper towel. 
    3. Fold the paper towel into a small square so that the baking soda is enclosed and will not leak out the sides. 
  3. Measure 1/2 cup vinegar and 1/4 cup warm water, then pour both into the plastic bag. 
  4. Now, you will need to move quickly! You may need a partner to help you out. You will need to hold your Ziplock bag open and place the time-release packet into the bag. The tricky part is that you need to zip the bag shut immediately after inserting the time-release packet. If you have a partner, have them put the packet in so you can focus on zipping the bag shut.  
  5. Shake the bag up for a few seconds and then place it in the sink (or on the ground, if you’re outside). 
  6. Record your observations!


What exactly happened and why?


EXPLANATION
Baking soda is a base and vinegar is an acid. When the two mixed together, there was an acid-base reaction! When the reaction occurred, it created carbon dioxide, which is a gas. The gas is what created those bubbles that blew up your Ziplock bag. 


Now that you have seen an acid-base reaction first-hand, you are going to try another one. This one will take a little longer to occur, so you won’t be able to watch the whole process.


YOU WILL NEED
  • Two eggs
  • Vinegar
  • Two glasses
  • Saran wrap
  • A soup spoon


YOU WILL DO
  1. Place one egg carefully inside each glass.
  2. Pour enough vinegar to cover both of the eggs. You should see bubbles form on the eggs’ shells. Why?
  3. Cover both glasses with saran wrap and put them in the refrigerator.  
  4. Wait 24 hours.



Predict: What might the vinegar do to your eggs?



  1. Use a soup spoon to CAREFULLY scoop the eggs out of the glass. What do they look like so far?
  2. Dump the vinegar into the sink and then place the eggs back into the glasses.
  3. Fill the glasses with enough fresh vinegar to cover the eggs, and place them back in the fridge for 24 more hours. 
  4. Once again, use a soup spoon to carefully remove the eggs from the glasses. 
  5. What do the eggs look like now?!



WHAT HAPPENED?
The eggshell is made up of calcium carbonate, which is a base. Referring to the experiment you already did with baking soda and vinegar, what do you think happened when you put the eggs into vinegar? Why? How was this experiment similar or different from the one above? 



Extension: Learn about Osmosis! 

Now that you have two shell-less eggs, let’s try a new experiment with them as an introduction to osmosis.

FIRST: What is osmosis?
Picture
Image 1: Osmosis in action. Water moves through a semi-permeable membrane towards a higher concentration of solute.
Picture
Image 2: Movement of water in hypertonic, isotonic, and hypotonic cells
A hypertonic solution has a higher concentration of solute outside the cell, therefore less water, than in the cell, while a hypotonic solution has a lower concentration of solute outside the cell than in the cell. 


An isotonic solution is “at peace.” It has an equal amount of solute outside the cell than inside the cell.


What is solute and what is a solution? 

An example of a solution is sugar water. The solute (substance to be dissolved) is the sugar and the solvent (the substance doing the dissolving) is the water. 
​
Learn more about solutions and mixtures
What does this all mean? 

Basically, a cell within a hypertonic solution will shrink, as the movement of water goes from the cell to the solution. A cell within a hypotonic solution will swell, as the movement of water goes from the solution to the cell. A cell within an isotonic solution will stay the same, as the water moves in and out of the cell equally. 


Check this science rap to help you remember these osmosis terms and learn more about where osmosis occurs in real life! ​
Click to set custom HTML
Let's start our activity!
Goal: See what happens when you put an egg in a hypertonic solution versus a hypotonic solution. 

YOU WILL NEED
  • Two glasses
  • Two naked (shell-less) eggs
  • Corn syrup
  • Water
  • Soup spoon


CHECK FOR UNDERSTANDING
  • Is the corn syrup hypotonic or hypertonic?
  • Is water hypotonic or hypertonic?




Predict: How will your two eggs differ after hours? 


Here's what to do! 

  1. Place each egg in a clear glass.
  2. Fill one glass with enough water to cover the egg.
  3. Fill the second glass with enough corn syrup to cover the egg. 
  4. Place both glasses in the refrigerator for 24 hours. 
  5. Take both glasses out and record your observations. 


What do your eggs look like? How do they differ? Why did this happen?


What do you think would happen if you now placed the eggs in opposite solutions? Try it out! 


  1. Put the corn syrup egg in a glass of water and the water egg in a glass of corn syrup. 
  2. Place in the refrigerator. What do they look like after 24 hours? 
  3. Record your final results. 




References
  • https://www.exploratorium.edu/cooking/eggs/activity-naked.html
  • https://www.exploratorium.edu/cooking/eggs/activity-nakedexperiment.html
  • http://www.exploratorium.edu/science_explorer/bubblebomb.html
  • http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/acidbase.html
  • http://www.microbelibrary.org/library/biology/3120-osmosis-a-cell-in-an-environment-that-is-hypotonic
  • http://www.chem4kids.com/files/matter_solution.html
Image and video credits, in order of appearance:

CrashCourse, 2013. Acid-Base Reactions in Solution: Crash Course Chemistry #8. Uploaded from Youtube on 8/15/2016. ​https://www.youtube.com/watch?v=ANi709MYnWg&feature=youtu.be

Openstax, 2016. The process of osmosis over a semi-permeable membrane, the blue dots represent particles driving the osmotic gradient. Image uploaded from Wikimedia Commons on 8/15/2016. 
https://upload.wikimedia.org/wikipedia/commons/6/62/0307_Osmosis.jpg File used in accordance with the Creative Commons Attribution-Share Alike 4.0 International license. No changes were made. 

LadyofHats, 2007. Effect of different solutions on blood cells]]. Image uploaded from Wikimedia Commons on 8/15/2016. ​
https://upload.wikimedia.org/wikipedia/commons/thumb/7/76/Osmotic_pressure_on_blood_cells_diagram.svg/553px-Osmotic_pressure_on_blood_cells_diagram.svg.png File released into the Public Domain. 

Sciencemusicvideos, 2013. Osmosis! Rap science music video. Uploaded from Youtube on 8/14/2016. https://youtu.be/HqKlLm2MjkI
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