Discovery Express

How do Peeps react to different temperatures? Make your own Peep slime!

2/21/2019

Author: Maddie Van Beek

Peeps and Temperature
Last week was Valentine’s Day, so you may have some leftover candy to use up! One classic Valentine’s Day Candy you might have is marshmallow Peeps (you might see these more at Easter, but the heart ones have become popular!). How exactly are Peeps (or any marshmallows) made?

List the ingredients that you think might be in marshmallows.

The answer: Sugar, gelatin, water, and AIR. Marshmallows are mostly made of sugar that has been whipped to include lots of tiny air bubbles. Marshmallows start out as a liquid sugar mixture, and then gas is incorporated to form an airy foam. In the past, marshmallows used to contain the root of the marsh-mallow plant for medicinal reasons, but you won’t find any marsh-mallow root in most marshmallows you see today. Now, we mostly enjoy marshmallows as a fun, sweet treat.

Heat a Peep!
What happens when you heat something? Molecules begin to move faster as they are heated, which causes them to expand. When something is cooled, the molecules begin to slow down and become more uniform.

When you heat a marshmallow, those air pockets that are already part of the foam expand, which causes your marshmallow to expand! As it cools back down, the marshmallow shrinks in size. If the marshmallow expands too much those air pockets burst, and the marshmallow cannot re-expand.

Here is some more information about what happens when you heat a marshmallow:
https://www.exploratorium.edu/cooking/candy/activity-mallows.html

Let’s test this out!

1. Tear apart a row of Peeps (you’ll need 3 Peeps).

2. Measure each Peep and make sure they are the same size. (We found that each heart-shaped Peep was 4.25 cm across at the widest point.)

3. Place one Peep in the freezer. Wait for 10 minutes.

4. Leave one Peep on a plate at room temperature. This is your control Peep. You will compare your results from the freezer Peep and microwaved Peep to see how size has changed.

5. Make your predictions! Will the freezer Peep change in size? Why? Will a heated Peep change in size? Why? Think about what you read.

6. After your 10 minutes is up, remove the freezer Peep. Below, the one on the left is the freezer Peep. The one on the right is the control Peep. The freezer Peep did not shrink noticeably.

7. Heat the remaining Peep in the microwave for 1 minute. Watch what happens!

8. Record your results.

Findings: We found that the freezer Peep stayed about the same size, but felt much firmer; the air molecules probably condensed and the cold made the sugar molecules lose their elasticity, making the marshmallow denser. The heated Peep grew immensely in size! The measurement across was over 7 cm, but it also expanded in height and length. It grew to its largest size after about 40 seconds. Once the Peep cooled, it was small, dry and crunchy. If you break it open, you might even see that it's a little burnt inside.

Next, you’re going to heat the remainder of your Peeps to make some Peep slime!

Notice that Peeps are made of sugar, corn syrup, and gelatin. All ingredients that we’ve used to make slime in the past!

YOU WILL NEED:
* Peeps (at least 5)
* Corn starch
* Powdered sugar
* Microwave safe bowl

Here’s what to do!

1. Tear apart at least five Peeps and put them in a microwave safe bowl.

2. Add 1 tablespoon of vegetable oil.
3. Heat your Peeps for 30 seconds. Watch what happens as they heat up!

4. Remove your Peeps from the microwave and stir them lightly with a spoon.

5. Sprinkle 1 tablespoon of corn starch into your Peeps and continue stirring. Note any texture changes.

6. Sprinkle a second tablespoon of starch into the Peeps—at this point, you may need to start mixing with your hands. Fun!

7. What does your slime look like? Feel like?

8. Add a final tablespoon of starch and your slime should be ready to go!

9. Add sprinkles for more fun!

10. What do you think happens if you reheat your slime? Try it!

11. We noticed it got a lot more goopy and sticky. Why do you think this is? Remember, your marshmallows started out with a lot of air bubbles… what do you think is happening as you continue to heat and play with the marshmallow slime? Add cornstarch again to get more of a dough-like feel.

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Exploring the Mpemba Effect

2/6/2019

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Author: Maddie Van Beek

Fargo has been FROZEN the last few weeks! In the spirit of winter, we’re going to learn about a few frozen phenomena.

These are the questions we'll be exploring today!

What is a polar vortex?
What is wind chill, and how does it work?
What is the Mpemba effect?
What freezes faster, hot water or cold water? Why do you think that?

Make some predictions. Write down what you know about each question.

First of all, let's talk about the Polar Vortex.
Maybe you’ve never heard of a polar vortex before, but they exist at the poles all the time! A polar vortex is a large, low-pressure area of cold air located near the North and South Poles. In the winter, the Northern polar vortex sometimes weakens and expands. Below, the picture on the left shows a strong polar vortex that is well defined. On the right is an example of a weak polar vortex that has expanded.

This expansion causes especially cold temperatures, which is what we’ve been dealing with lately. So if you hear the term “polar vortex,” don’t worry! This is nothing new! We just have to dress extra warm and be careful when it’s this cold outside.
Check out Scijinks (https://scijinks.gov/polar-vortex/) for a great explanation of how a Polar Vortex works!

Windchill
Because of this polar vortex, you might have heard people talking about the intense wind chill that we've been having. A -10 degree (Fahrenheit) day with a little extra wind suddenly feels much colder! So, does windchill affect everything? Will objects freeze faster because of higher windchill? This is a tricky question. Only living things are affected by windchill. That's why you see the term "real feel" when there is a significant windchill. The air stays the same temperature, but living things feel colder because of the wind.

Check out the windchill chart below. What do you notice? When the air is warmer, high wind speed doesn’t make as much of a difference in wind chill. When it’s cold, however, a little wind goes a long way!

When you go outside, the windchill can be dangerous because you FEEL as though the air temperature is much colder. Inanimate objects, however, only cool down to the air temperature. For example, if you leave a glass of water outside when it is 34 degrees, but it "feels like" 20 due to the wind chill, the water will not freeze. The wind DOES cool inanimate objects down more quickly than if the air was still, but it will only ever cool to the air temperature.

Mpemba Effect
Now, let’s go back to one of our first questions: which freezes first, hot water or cold water? You might have predicted that cold water would freeze before hot water, because that seems like the most logical answer! The hot water should take longer to cool off and get to freezing temperature than cold water, right? Well, sometimes that's not the case. In certain circumstances, hot water can freeze more quickly than cold water. This is called the Mpemba Effect.

The history behind the Mpemba Effect started with ice cream. Erasto Batholomeo Mpemba noticed in 1963 that when he put hot ice cream mixture and cold ice cream mixture in the freezer, the hot mixture sometimes froze more quickly. This sparked more interest in studying which water temperatures freeze faster.

There are many explanations suggested for the Mpemba effect. One is that some of the heated water evaporates, so less liquid ends up needing to be frozen than the same amount of cold water. Another is that cold water tends to freeze from the top down, while warm water freezes from the bottom up. In the first case, the top layer of ice insulates the rest of the water, and thus the water takes longer to freeze. Density is another factor that has been suggested; hot water is less dense which could allow for quicker cooling.

Unfortunately, the Mpemba Effect is yet to be fully explained! Results are often inconsistent, making it hard to understand exactly why hot liquid sometimes freezes faster. Can you explain the Mpemba Effect? Test it out for yourself!

YOU WILL NEED:
* 4 identical containers with caps
* Tape and writing utensil
* Paper to write down your observations
* Water
* Freezer or temperatures colder than 32 degrees Fahrenheit.

Here's what to do!
1. Gather your four identical containers. Label two of them "hot" and two of them "cold."

2. Turn your water on, and let it get as cold as possible.
3. Measure 1/2 cup of water and pour it carefully into your first container labeled “cold”. Seal with the lid. (If you don't have lids for your containers, use plastic wrap).
4. Measure 1/2 cup of cold water and pour into your second “cold” container. Leave this container open.
5. Turn your faucet to the hot setting, and measure 1/2 cup of hot water into the container labeled “hot”. Seal with the lid.
6. Repeat with the second “hot” container, but leave the lid off.

7. Place all four containers outside on an even surface (or in the freezer if you live somewhere warm).
8. Write down your prediction. In which order will the containers freeze? Why?
9. Set your timer and check on your containers every 15 minutes. Write down your observations.
10. After 90 minutes (when you can see significant freezing taking place) bring your containers inside. Which container contains the most ice? The least ice? Which one started to freeze first? Last? Do your results match your prediction?

Observations for round 1:
After 15 minutes, the hot containers had melted into the snow, but no freezing had taken place. Notice the condensation in the containers, especially in the ones with hot water.

After 30 minutes, the Cold/Open container formed a thin layer of ice at the surface.

The hot/open container had a nice layer of frost where the water evaporated, but the surface was not frozen.

After 45 minutes, the cold/open and the cold/closed containers clearly had a layer of ice at the surface. The hot/open and hot/closed still did not.

After an hour, the hot/open and hot/closed containers finally had thin layers of ice.

Results after 90 minutes (in order of most frozen to least)
We broke up the ice in order to tell which had frozen the most.

We repeated the tests four times, and the results of tests 2, 3, and 4 were the same.

If you’re having trouble being able to see which is more frozen, hold the containers up to the light (you can see the water moving) or look at the bottom of the containers.

Findings:
In our testing, we never observed the Mpemba effect. We repeated the test four times under the conditions below.
1. 1 cup of water/container outside in -20 degrees F, 3 mph wind, on snow.
2. 1/4 cup of water/container in -20 degrees F, 7 mph wind, on baking sheet.
3. 1/2 cup of water/container in -20 degrees F, 10 mph wind, on baking sheet.
4. 1/2 cup of water/container in a normal freezer (no wind).
However, we DID determine that the open containers froze faster than their sealed counterparts. Each time the order of freezing was cold/open, cold/closed, hot/open, hot/closed. Why do you think that might be?

Another note: The cold containers froze from the surface first, while the Hot containers seemed to freeze more uniformly from the sides of the bottles.

Did you observe the Mpemba effect? If not, what factors might be worth testing? You could try the same experiment with different containers (example: glass instead of plastic or wide mouth instead of narrow).

Images:
Polar Vortex and Windchill Chart are Public Domain images found in Wikimedia Commons.
Photographs of experiment taken by Maddie Van Beek.

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Edible Gelatin Slime Version 2

1/15/2019

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Today, we’re going to make a new version of EDIBLE SLIME using gelatin!

In the past we’ve made several different versions of slime. Slime can be made with many different ingredients, including glue, borax, cornstarch, potato starch, or gelatin. Today, we’ll be using gelatin AND cornstarch to make a fun-to-play-with, taste-safe slime!

First, let’s learn a little bit about our ingredients. Both gelatin and cornstarch are used as thickeners; gelatin is usually used in desserts, while cornstarch is commonly used in gravies or sauces. While they both do the same job, they perform it differently.

Gelatin is a protein that comes from the collagen in animal skin, bone, or connective tissue. In order for gelatin to achieve its full thickening powers, it needs to be heated. Once it cools, it thickens, or gelatinizes. You may remember this happening if you made our Cranberry slime on Thanksgiving, or our edible gelatin slime on Halloween.

Starch is a carbohydrate that comes from a variety of plants and grains, such as corn, potatoes, or rice. Cornstarch also needs to be heated in order to thicken foods. When starch is heated, the molecules swell and absorb water, thus making the food thicker or creamier. That’s why you may have seen your mom adding cornstarch or flour (which contains starch) to gravy to make it thicker.

While cornstarch and gelatin are different in some ways, both thickeners require heating to do their work. Cornstarch thickens food as it is heated, but gelatin thickens food as it cools.

Now that you know a little bit about the ingredients you’ll be using, LET’S MAKE SOME SLIME!

YOU WILL NEED:

* One package of sugar-free gelatin dessert
* One package of regular gelatin dessert
* ½ cup cornstarch
* Water
* Mixing bowl
* Measuring cup
* Spoon

Here’s what to do!
1. Measure ½ cup of cornstarch into your mixing bowl.

2. Tear open your package of sugar-free gelatin and dump the whole thing into the mixing bowl.

3. Mix the cornstarch and gelatin powder together so they are evenly distributed.

4. Pour a little water into the powdered mixture. Notice the sudden change in color!

5. Mix the water in and continue to add a little bit at a time. You will need to keep scraping the sides of the mixing bowl to get all the gelatin and cornstarch to mix together with the water.

6. Once you have a good clump of slime, pick it up and starch working any dry spots into the mixture. Your finished product should feel kind of like a firm but squishy play-dough.

7. If your slime is cracking or crumbling, add a little more water. If it seems too goopy, sprinkle in a little more cornstarch.

Now, compare your sugar-free gelatin slime to slime made with regular gelatin. Repeat steps 1-7, but with regular gelatin. If you use a large package of gelatin (the 6 oz) only use half of the powder.

What differences do you notice between the two slimes? Why do you think this is?

Take a look at the ingredients in each gelatin dessert. Everything else you did should have been exactly the same, yet the slimes turned out very different in consistency. The only difference was that the first slime was sugar-free.

Findings:
The first sugar-free slime is almost like a dough. You can form it into different shapes, flatten it, and tear it apart.

The regular gelatin slime became runnier with less water, and was more like your typical non-Newtonian slime. When you apply any pressure, it behaves like a solid. You can roll it in a ball and it holds its shape. When you stop applying pressure, it oozes through your fingers like a liquid.

The ingredient list in regular gelatin dessert and sugar-free gelatin dessert is almost the same. The regular gelatin dessert contains sugar while the sugar-free uses aspartame. You wouldn’t think this would make such a difference in consistency of our slimes. BUT there is one other ingredient added in sugar-free gelatin dessert: maltodextrin. Maltodextrin is formulated from cornstarch! Maltodextrin is commonly used in candies and desserts to improve consistency and thickness. This explains why the sugar-free slime ends up firmer and doughier than the regular gelatin slime!

Have fun playing with your slime! If you mix the two slimes together, they form a slime that’s perfectly doughy and gooey!

To save your slime, seal in a plastic bag and put in the fridge. To rehydrate the slime when you want to play with it again, add a little water.

More slimy recipes:
https://www.discoveryexpresskids.com/blog/spud-mud
https://www.discoveryexpresskids.com/blog/edible-slime https://www.discoveryexpresskids.com/blog/cranberry-slime https://www.discoveryexpresskids.com/blog/christmas-slime https://www.discoveryexpresskids.com/blog/edible-holiday-slime https://www.discoveryexpresskids.com/blog/two-times-the-slime-fun-with-polymers

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Christmas Candy and Phase Changes

12/30/2018

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Author: Maddie Van Beek

Today, we're going to use our Christmas candy to learn about phase changes!

Why do things melt?

Melting is actually a scientific process called a "phase transition." There are three different physical phases of matter: solid, liquid, and gas.

Every item you see around you is made up of molecules. Molecules are the building blocks of everything! However, the structures that molecules form are not necessarily permanent; they can undergo physical or chemical changes. Let’s explore this:

Grab a handful of gumdrops and make a square. Pack them as closely together as possible in neat lines. This is what the molecules in a solid phase object look like. The molecules are in a nice, tight order, and can hardly move. If a solid is heated, the molecules start to shift.

The next phase is liquid. Move the gumdrops a little further apart from one another. They might not be in straight lines, but they are still fairly close together. Liquids can move and shift and change shape, but the molecules still sort of stay together. Picture an ice cube left out in the sun. After a short amount of time, the ice begins to melt. Ice melts at 32 degrees Fahrenheit, but every substance melts at a different temperature. The point at which a solid changes to a liquid is called the melting point. Even rocks can melt if they are heated to a high enough temperature!

Heat a liquid even more, and the phase changes from liquid to a gas. Move your gumdrops even further apart from each other. They don't need to be in any sort of pattern at all. When a substance is in the gas phase, the molecules can spread apart and fill a whole room! For example, when water is heated, it evaporates into the air! What's another gas you can think of?

Recap:
Now you know the three physical phases: solids, liquids, and gases. Heat causes a phase change from solid to liquid, or from liquid to gas. Every substance has a different melting point, the point at which a solid changes to a liquid. Why do some objects not melt at all?

Some substances, when heated, will combust (burn) before they ever melt. Instead of staying solid until they reach their melting points, they react with oxygen and burn instead. This reaction is a chemical change. For example, if you burn a piece of paper, it changes form from paper to ashes. This chemical change is irreversible; you cannot change ashes back to paper.

Make a list of items you think would melt, like a plastic toy, and a list of items you think would burn, like a piece of paper.

Recap:
Items that melt, like ice melts into water, are undergoing physical phase changes.

Items that burn, like paper or wood, are undergoing a chemical change.

Now, let's start our experiment!

YOU WILL NEED:
A variety of Christmas candy

-Candy Cane
-Chocolate
-Peppermint Oreo
-Gumdrops
-Stove
-Saucepan
-Paper and pencil

Here's what to do!
1. Make a list of the Christmas candy you have.
2. Next to the name of the candy, draw an X if you think it will melt. Draw a circle if you don't think it will melt.
3. Now, number the items from 1-4 based on which you think will melt first to last (1 is fastest, 4 is slowest).
4. Place the saucepan on the stove, and turn the heat to medium-low.
5. Place the unwrapped candy cane in the center of the saucepan.
6. Time how long it takes for the candy cane to start melting. Record what you find.
7. Carefully rinse out your saucepan with cool water, and wipe clean.
8. Place the saucepan on the stove, and repeat the process with the Oreo, the chocolate, and the gumdrops.
9. Compare your results to your guesses.
10. So, which item has the lowest melting point? Which one has the highest melting point?
Results:
The Oreo was the same from 0-10 minutes. The frosting softened, but the cookie remained unchanged.

The candy cane began to noticeably melt after about 4 minutes and fully melted after another two minutes.

The chocolate started to melt in less than two minutes and was fully melted after 2 min.

The gumdrops took the longest, by far! They started to melt after about 7 minutes. They were melting much more noticeably after about 10 minutes.

Make window decorations by melting gumdrops and candy canes!
1. Preheat the oven to 400 degrees Fahrenheit.
2. Cover a baking sheet with tin foil.
3. Place a cookie cutter on the tin foil.
4. Fill the cookie cutter with gumdrops. Be as creative with your design as you wish, but make sure to pack them tightly so there isn’t any space in between the gumdrops.

5. Place your design in the oven, and check every five minutes. It should take about 15 minutes to melt together.

6. Remove from the oven, and let cool. Carefully remove your gumdrop design! You may need to use a butter knife to help loosen the corners.
7. Repeat with crushed candy cane or hard candy for a stained glass look! For the candy cane, reduce the temperature to 350 degrees, and it should only take 7 minutes to melt (check every minute after 5 minutes). It is difficult to remove the
design from the cookie cutter once it solidifies, so don’t worry if it breaks. It still looks like cool stained glass! (You could also try lining the inside of the cookie cutter with tin foil to make it easier to remove the shape.)

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Sedimentary Rock Bars

12/13/2018

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Author: Maddie Van Beek

Today, we’re going to learn about sedimentary rocks!
There are three main types of rocks: igneous, metamorphic, and sedimentary.

Igneous rocks are: formed from magma or lava and are found at the Earth’s crust.
Metamorphic rocks are: formed from high temperature and/or high pressure.
A metamorphic rock is created by changing or “morphing” another existing rock into something new.
Sedimentary rocks are: formed from layers of sediments at the Earth’s surface. This is what we are focusing on today!

Think about the word sediment… does it mean anything to you? Brainstorm what sediment might mean or what the word sediment reminds you of.

Sedimentary rocks are formed over time at the Earth’s surface by a variety of processes (air, ice, water, wind, and/or gravity). You might find sedimentary rocks close to the ocean, for example. Waves and bodies of water cause different materials to wash ashore and form layers and layers of deposited particles. As layers are added, pressure increases. Over time, these layers get compressed from loose sand, pebbles, minerals, or seashells into hard layers of rock. When rocks form this way, it's called lithification.

These rocks are along Mystic Beach near Sooke, British Columbia.

When the tide is high, it coves the beach completely and reaches all the way to the rocks.

Think about it, which layers of sedimentary rock are the oldest? How do you know?

Which layers are the newest? Why?

When you see sedimentary rocks, you may notice different textures and colors. This is because they have been formed over a long period of time from many different materials.

These rocks are along Monterey Bay at Point Lobos in Carmel, California.

Now that you know what sedimentary rocks are and how they form, we’re going to form our own EDIBLE sedimentary rock bars!

YOU WILL NEED:
* Butter
* Marshmallows
* Puffed rice or rice crisp cereal
* Caramel or chocolate chips
* Toppings (any kind of candy, chocolate or popcorn will do)
* Rubber spatula
* Baking Pan
* Saucepan

Here’s what to do!
1. Melt 2 tablespoons of butter in a saucepan over low heat.
2. Add 2 cups of marshmallows and stir over low heat until the butter and marshmallows form a fluffy sauce.

3. Remove the melted marshmallow from the stovetop and add 2 cups of puffed rice cereal (or whatever cereal you choose to add).
4. Spread your first layer of marshmallow cereal into the baking pan. Pack it down! Remember, this is your oldest sedimentary layer, so it should be very firm since it’s been under all that pressure!

5. Next, add a layer of caramel sauce. Spread it evenly over the marshmallow layer.

6. Now, sprinkle puffed rice over the caramel and press it all in! This layer is probably not packed down as much as your bottom layer, but should still be pretty stuck in there.

7. Melt about ½ cup of chocolate chips in the microwave OR use 4 tablespoons of coconut oil and 4 tablespoons of cocoa powder. Either will work! Microwave for 30 seconds at a time, stirring in between until you have liquid chocolate. Drizzle the chocolate sauce over the puffed rice layer and then spread it over evenly with the spatula.

8. Finally, add your toppings! These toppings are probably the largest pieces and the least packed down. You can use M&Ms, a crushed candy bar, or popcorn! Use your imagination and your resources!

9. Refrigerate your sedimentary rock bars for at least 20 minutes to solidify.
10. Cut your bars apart and enjoy! Make sure to pay attention to all the different layers you’ve created!

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Cranberry Slime

11/27/2018

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Author: Maddie Van Beek

It's past Thanksgiving, your grandparents went home, and you're still probably feeling sleepy from all that Turkey and pumpkin pie. One great thing about the week after Thanksgiving is all the leftovers! What to do with all that cranberry sauce... we're going to make cranberry SLIME!

This activity is similar to the edible slime we made last month. This time, we're using cranberry sauce in replacement of corn syrup. The sugar and water in the sauce acts similarly to corn syrup, and the cranberries add even more texture (and flavor!) to the slime.

The Science:
Gelatin is an interesting substance. When heated it becomes a thin liquid, but it thickens as it cools. Once cold, the texture is very firm, but it will go right back to liquid if you heat it up again! This means it is thermoreversible.

Gelatin comes from collagen, which is derived from animal connective tissue. You might not think of "Jello" as healthy, but gelatin is almost all protein, and can actually be good for us, as long as we're not adding too much sugar or artificial coloring. So, snack away!

How does sugar compare to corn syrup? Although sugar is not a thickening agent, it does make water thicker once it's dissolved. When you heat sugar and water together, they form a thin syrup, similar to corn syrup. Both sugar and corn syrup are used as sweeteners, and they should both be consumed in moderation. Sugar comes from sugarcane or sugar beets, and corn syrup, obviously, comes from corn. While sugar is made of sucrose (fructose and glucose bound together), corn syrup is made of glucose and fructose that stay separate. Corn syrup is often used in candy recipes because its smooth texture makes it easy to create caramels and hard candies without any clumping or crystallization issues.

Let's get slimy!

YOU WILL NEED:

Cranberry sauce (cranberries, water, sugar)
Gelatin (we used natural beef gelatin: Knox packets work great, too!)
Stove
Mixing bowls
Spoon
Sauce pan

Here's what to do!

First, you need to make your cranberry sauce (if you don't already have some). This simple recipe is super easy. Measure 1/2 cup of water into a saucepan. Turn the heat for the burner on medium high.
Measure 1/2 cup of sugar into the water and stir.
Add 1 cup (about 1/2 pint) of cranberries into the sugar water and leave to boil.

4. Pay attention to what happens to your cranberries... within minutes, the skin starts to crack. Soon, they expand, and then pop! You might see this happen almost immediately, or it could take a few minutes.

5. Let the cranberry sauce simmer for about 10 minutes. You'll notice the liquid begins to thicken slightly and get darker in color.

6. Remove sauce from heat, let cool for a few minutes, and then pour into a mixing bowl.
7. Put the bowl of cranberry sauce in the refrigerator to chill while you move on to your next step: Dissolving the gelatin.
8. Measure 1 cup of water into a sauce pan and sprinkle 6 tablespoons (or 6 packets) of gelatin into the water.
9. Heat over medium heat on the stove top, stirring constantly.
10. Once the gelatin is dissolved, the water will look kind of yellow-ish. Remove from heat and set the gelatin aside to cool for about 10 minutes.

11. Once your time is up, take the cranberry sauce out of the refrigerator. Pour the gelatin mixture into the cranberry sauce and stir. What happens?!

12. The liquid sauce begins to thicken! If your gelatin is still warm, it will take a few minutes to really get thick and slimy. Gelatin thickens as it cools, so you'll notice the consistency change as you continue to stir and play with your slime.

Within 2 minutes.

After about 5 minutes.

Another few minutes... ewwww, SLIME!

13. Taste your slime, if you dare!
14. If you put your slime in the refrigerator, it will harden into a gel. If you want to play with it again, just heat it up in the microwave for about 40 seconds.

After heating for 40 seconds and then refrigerating for 1 hour.

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Cranberry Decoder

11/15/2018

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Author: Maddie Van Beek

Reveal secret messages with cranberry juice!

Thanksgiving is coming up soon, which means besides lots of family time, you'll probably be eating all kinds of Thanksgiving treats!

What's your favorite Thanksgiving dish?!

One common side dish to go with your turkey is cranberries! How did cranberries become such a Thanksgiving Day staple?

All About Cranberries

Cranberries are actually native to North America, and Native Americans used cranberries as food, dye, and in medicine. It's said that the Pilgrims enjoyed cranberries when they first came to America, and we still use them in our Thanksgiving meals today!

One reason that cranberries are so good for us is because they are full of antioxidants.

Today, we're going to use cranberry juice as a secret message decoder. The reason that we're using cranberries is because they contain an antioxidant (also a pigment) called anthocyanins. Anthocyanins arewhat gives cranberries their deep red color. We've talked about different pigments such as anthocyanins when we made homemade veggie paint.

Check that out here for more artsy fun: https://www.discoveryexpresskids.com/blog/painting-with-veggies

Anthocyanins don'g just appear in cranberries; you can find anthocyanins in lots of other dark red fruits and vegetables, such as purple cabbage, blueberries, and cherries.

When anthocyanins arecombined with either a strong acid or a strong base, the purply-red color changes! Let's test it out.

Let's think... what in your house is an acid?

-Lemon juice, vinegar, orange juice

How about a base?

-Baking soda, some cleaners

We're going to use baking soda as our base and lime juice as our acid (lemon juice will work just as well).

Pour about an inch of cranberry juice in three different clear glasses. Add a tablespoon of lemon or lime juice to one, and a tablespoon of baking soda to another. What happens? You'll notice that the acid made the cranberry juice a brighter, lighter red, and the baking soda turned the cranberry juice a darker, purply-blue. If you add more, does it continue to change color? Try it!

Now that you know how anthocyanin reacts with acids and bases, lets move on to our secret message writing!

YOU WILL NEED:

Cranberries or cranberry juice
Lemon or lime juice
Baking soda
Paper
Paint brush
Cups
Water

Here's what to do!

Using lemon or lime juice, write a secret message or design on your paper. Wait for it to dry.
Mix a few tablespoons of baking soda with water (you don't need a lot of water). Stir until dissolved.
Using your baking soda mixture, write a second message/design on your paper. Wait for it to fully dry.

(I used the baking soda mixture for the top and lime juice for the bottom)

4. Now for the decoding process! If you have cranberry juice, you're all set. If you have cranberries, you'll need to boil them for about 30 minutes to extract the juice/anthocyanins. Wait for the juice to cool before using.
5. Once your paper is dry, pour your cranberry decoder into a glass. Use a paint brush to coat your paper, or just get messy and dump some of the juice over the paper. You could also use a spray bottle for less mess and clearer messages. What happens?!
6. Message decoded! You should have noticed that your baking soda writing turned a greenish-blue (you might have even seen some fizzing), and your lime juice writing got brighter.

Notice the fizzing from the acid in the juice mixing with the baking soda!

While the top word (written with baking soda) fizzed, the bottom (written with lime juice) appeared immediately.

As the paper got soaked in cranberry decoder and then started to dry, the baking soda writing turned a greenish color!

7. Continue writing messages or create some fun color-changing art!

Extension: Find other things in your home to test out in your decoding art. Try other acidic fruits as your message ink... you might find that some turn out different shades than others. This is because anthocyanins react with acids and bases differently depending on their pH levels. You could also try different fruit juices with anthocyanins. Test away and have fun!

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Edible Slime

10/31/2018

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Author: Maddie Van Beek

In the spirit of Halloween, we thought we’d have some more SLIMY SPOOKY FUN! Last week we made slime out of potato starch. This week, we’re going to use gelatin and corn syrup to make edible slime!

Gelatin is a product that is extracted from animal parts (usually the skin, bones and hooves of pigs or cattle) and is used for thickening certain foods. Gelatin comes from collagen, which is found in the connective tissue. You might not think of gelatin as healthy, but it is almost all protein. When gelatin is heated, the protein bonds break and form a liquid, but when it is cooled, the protein strands twist together and form a gel.

One special thing about gelatin is that it is thermoreversible, which means it thins as it is heated and thickens when it is cooled. Thermo comes from the Greek word thermos, which means heat. The Latin word reverses means to turn back. So thermoreversible means heat causes the substance to “turn back," or return to a fluid state when heated.

Because of its thickening properties, gelatin is used in many sweets and candies. It is flavorless and almost completely colorless, so it can be easily dyed and flavored.

Luckily, all these properties make gelatin perfect to use for our SLIME!

YOU WILL NEED:
* Gelatin (we used natural beef gelatin, but Knox gelatin packets will work well)
* Corn syrup
* Water
* Measuring cups
* Food coloring
* Saucepan
* Stove
* Mixing bowls
* Flavoring of your choice (any drink mix works well)

Here’s what to do!
1. Measure 1 cup of water into a saucepan and bring to a boil.
2. Add a few drops of food coloring of your choice to the boiling water.
3. Measure 6 tablespoons of gelatin into the water, stirring constantly.

4. Once the gelatin is dissolved, remove from the heat and set aside for 5-10 minutes to cool.

5. Measure 1/2 cup of corn syrup into a separate mixing bowl. If you want your slime to have a certain flavor, add two tablespoons of flavored drink mix to your corn syrup and stir until evenly distributed.
6. Pour the gelatin mixture over the corn syrup and stir… you should start to see the texture change right away.

7. Mix together and watch your slime form!

8. It may take a few minutes to thicken; as the gelatin cools the slime will get even thicker and gooier.

9. Play, taste, enjoy!

Extension: What happens when you put your slime in the refrigerator? How about the microwave? Make a prediction! Think back to what you learned about gelatin being thermoreversible.

You can actually turn this edible slime into a gummy!
This is what happens if you put your slime into the refrigerator:

Spoon some slime onto a tray and refrigerate for creepy looking slimy treats.

OR

Heat your slime for 45 seconds in the microwave and stir; notice, your slime is now completely smooth again like it was before it thickened. Pour the slime mixture into a tray and place in the refrigerator for 10 minutes. Check your slime—it should be completely firm. If it’s still gooey, wait another 5 minutes. Remove from the refrigerator and slice into bite size pieces or gummy snakes!

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Spud Mud

10/20/2018

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Author: Maddie Van Beek

Get in the Halloween mood with some slime! Today, we’re going to make slime with potato starch… aka SPUD MUD!

First, what exactly is starch? There are all sorts of important nutrients in our diet. Think about what humans need to survive. Make a list.

Carbohydrates are a crucial source of energy in the human diet and are most readily used when our body is active. One carbohydrate that we get from many of our foods is starch.

Starch is a carbohydrate found in a variety of plants and grain products, such as potatoes, pasta, or rice. Starch is stored within the plant as an energy source, and is one of the most common carbohydrates in the human diet.

One thing that we use pure starch for is to thicken foods. If you try to mix starch with water or other cold ingredients, it will eventually settle to the bottom. If starch is heated, the molecules swell, and the tiny grains of starch absorb water. Once that water is trapped in the starch molecules, the food thickens. When the food is removed from heat, it will thicken even more as it cools. For more on how starch thickens foods, click here to check out our last blog and make some pudding! This time, we aren't going to heat our starch, we're going to use it to make a non-Newtonian fluid.

That brings us to our project: we're going to make our own spud mud! If you've ever made "Oobleck," then you know what it's like! This time, you’re going to try out potato starch instead of the commonly used cornstarch.

This weird slimy substance that you’re going to be working with today is a non-Newtonian fluid. Non-Newtonian fluids behave very differently from normal liquids or solids. Instead, they sometimes behave like a liquid and sometimes behave like a solid. When you apply pressure to a non-Newtonian fluid, it resists and behaves like a solid. As soon as you release the pressure, the fluid returns to liquid form.

To make this type of non-Newtonian slime, you need two basic ingredients: starch and water. Typically, cornstarch is used to make this kind of slime, but any type of starch will work. What about something else that contains starch, like flour?

Test this out: Compare potato starch to flour.
Scoop 1/2 cup of potato starch into one cup and half a cup of flour into a second cup. Mix 1/2 cup of water with each and stir. What happens?

Above, flour ball. Below, potato starch ball.

You probably noticed that the starch easily transformed into the slime you know and love, but the flour just left a goopy mess. Why didn't the flour work the same way? Think about what these two ingredients have in common. They are both powders, both processed, both from grains, but while potato starch is from potatoes, flour is from wheat. Potato starch is pure starch, while flour is a mixture of starch and proteins, such as gluten.

Add a few drops of food color if you would like. If your spud mud is too runny, add a little more starch. If it’s crumbly, add more water. A little goes a long way!

Next, we're going to try to extract our own starch from potatoes! Your job is to determine which potatoes have the most starch. This project requires some wait time,
so after you complete the first part of your project, you can continue to get messy with your spud mud!

Choose three different potatoes to compare. Some varieties of potatoes are "starchier" than others. There are starchy potatoes, such as Idaho or Russet, waxy potatoes, such as red or baby potatoes, and some that are in between. Sweet potatoes are also very high in starch content. New or "baby" potatoes have less starch, because they were harvested before much of their sugar could develop into starch. Out of your three varieties, which do you think has the most starch?

Make your predictions before you start.

YOU WILL NEED:
* Food processor or knife
* Large bowl
* Water
* Stove or microwave
* Strainer
* 3 Jars or clear bowls

Here's what to do!
1. Choose your first potato variety.
2. Wash the potatoes off well to remove any dirt.
3. Put two-three potatoes (of the same variety) in the food processor and process until they are in small chunks. You will need enough for two cups of chopped potato.

4. Scoop two cups of chopped potatoes into a large bowl.
5. Heat four cups of water over the stove.
6. Pour hot water over the potato chunks (just enough to cover them) and stir for 3 minutes. Notice that the water starts to change color as you stir!

7. Place a strainer over clear bowl or jar and pour the potatoes and water through the strainer (so you are left with only the starchy water)

8. Notice the texture and color of the water. What do you think will happen as it sits?
9. Over the next 10 minutes, check back every 2 minutes and write down any observations.
10. Repeat the process with the other two potato varieties. Make sure you use the same amounts of potato pieces, water, and jar size so results are comparable!
11. As you check back, you should see that the water has begun to separate. You might see a layer of water on the top or a layer of white on the bottom. The white layer is your starch!

Above, you can see the brown potato (left) and red potato (right) starting to form layers.
Below, the sweet potato formed a starch layer on the bottom within minutes.

12. Let all three jars sit as long as it takes to see good separation. You will begin to see layers within an hour or so, but it will be more obvious if you leave it for several hours or overnight.
13. Compare your results. Do you see any big differences? Does one potato obviously have more starch on the bottom than the other? Did your results match your predictions?

Notice the defined layer of starch on the bottom of the sweet potato glass.

Above, after two hours. Below, left overnight.

Dip your finger in the top layer—what does it feel like? Try pouring the top layer off of your potato water. The clear-ish colored layer should easily pour off, and you’re left with a thicker, goopier layer. Compare the consistencies between the different potatoes.

If you extracted enough starch, you could even use it to make more spud mud!

More starchy experiments:
Make your own gravy and test foods for starch: www.discoveryexpresskids.com/blog/science-of-starch

Compare gelatin and starch in two chocolate pudding recipes:
https://www.discoveryexpresskids.com/blog/cornstarch-vs-gelatin-make-your-own-chocolate-pudding

Get in the fall mood with some pumpkin slime: https://www.discoveryexpresskids.com/blog/fall-fun-make-your-own-pumpkin-slime

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Cornstarch vs. gelatin: Make your own chocolate pudding

10/2/2018

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Author: Maddie Van Beek

Corn Starch vs. Gelatin

Today we are going to learn about two different food thickeners, and compare their effects by making a delicious dessert! Why would we need anything to thicken our food? Can you think of any examples? Make a list.

One common food thickener is cornstarch. Many people use cornstarch to thicken gravies, soups, or sauces. The result is a creamier texture with an opaque appearance.

Another thickener is gelatin. Gelatin is more often used for custards, pie filling, or Jell-O® desserts. Unlike cornstarch products, gelatin allows foods to hold their shape more rigidly, and the appearance of these foods is typically more transparent.

While cornstarch and gelatin are different in some ways, both thickeners require heating to work their magic. Cornstarch thickens food as it is heated, but gelatin thickens food as it cools.

How exactly do these ingredients work?

Starch is a carbohydrate that can come from a variety of plants or grain products, such as potatoes, pasta, or rice. Starch is stored within the plant as an energy source, and is one of the most common carbohydrates in the human diet. If you try to mix starch with water or other cold ingredients, it will eventually settle to the bottom. As starch is heated, the molecules swell, and the tiny grains of starch absorb water. Once that water is trapped in the starch molecules, the food thickens. When the food is removed from heat, it will thicken even more as it cools.

Gelatin is a product that comes from collagen derived from animal skin or bone. In contrast to starch, gelatin is actually a protein. When mixed with cold ingredients, gelatin will not readily dissolve. Once heated, the protein strands lose their bonds with one another and the gelatin becomes a clear syrup. While warm, gelatin causes some thickening, but not much. Once cooled, the protein strands twist together, trapping liquid in between the amino acid bonds, creating a gel. The longer it cools, the firmer the gel becomes.

Now that you understand these two culinary ingredients, let’s move on to the fun part! Today you’re going to make two chocolate pudding desserts! Make sure you take notes along the way to compare your two recipes. Chart the differences in appearance, consistency, and at the end, taste!

YOU WILL NEED:
* 2 ¾ cups Milk
* 3 tablespoons Cocoa powder
* ½ cup Sugar
* 1 teaspoon Vanilla
* ¼ teaspoon salt
* ¼ cup Cornstarch
* 1 tablespoon Gelatin
* 2 Saucepans
* Measuring cups and spoons
* Mixing bowl
* Whisk and stirring spoon

If you want to track the differences side by side, prepare both recipes at the same time using two different saucepans.

Before you start, look at the cornstarch and gelatin. Write down observations, feel it, notice differences in texture. You may even try mixing each with a bit of water. What happens?

Here’s what to do!
1. Measure the dry ingredients, excluding the gelatin (sugar, salt, cocoa, cornstarch), into one saucepan and mix together. Set aside.

2. Measure the gelatin powder into the mixing bowl. Add ¼ cup milk and whisk together. You should see a thick paste. Don’t worry if the gelatin doesn’t fully dissolve. Set aside.

3. Measure the same amount of the dry ingredients, this time excluding the cornstarch (sugar, salt, cocoa) into a second saucepan. Add the remaining 2 ½ cups milk.
4. Measure 2 ¾ cups milk into the first saucepan of dry ingredients.
5. Place both saucepans on the stove over medium heat. Remember which one is which!
6. Stir both as they heat. You should notice the ingredients begin to dissolve as they heat.

Above, right after placing over heat. Cornstarch on the left, milk mixture on the right. Below, after a few minutes of heating and stirring.

7. After about five minutes, both saucepans should be relatively well mixed with no big clumps. Remove the gelatin pan from heat.

8. Continue stirring the cornstarch pan until it boils, and keep stirring until the pudding seems well-thickened. It will be darker in color and noticeably thicker. This process should take about 2 minutes after boiling.

Left, after pudding begins to thicken. Right, after two minutes of stirring after boiling.

9. Pour the heated milk mixture into the mixing bowl of gelatin and whisk until evenly distributed.

10. Scoop one cup of cornstarch pudding into a glass or bowl, cover, and refrigerate. Do the same with the gelatin pudding.
11. Now we wait! You can eat the leftover warm cornstarch pudding while you wait for your gelatin pudding to set. This will take about 2 hours.
12. Once two hours is up, remove both puddings from the refrigerator. Compare the appearance. Scoop a spoonful of each and compare consistency. Try them both! What do you notice? Record your results!

Above after two hours of refrigeration: Gelatin pudding on the left, cornstarch pudding on the right.

Results:
If you want a recipe that’s done fairly quickly, cornstarch pudding is the way to go. It’s thickened within 10 minutes or so, and can cool off in the fridge or even be eaten as a warm creamy treat (yum!).

Gelatin pudding does take a while to set, so you have to plan a few hours in advance. But the result is decidedly different! If you want a fancier dessert that holds its shape and can be layered (think different flavors, colors, or toppings) this is the way to go! Even the basic chocolate recipe we used settled into two different layers, which was really cool! The top layer was a little more jelly-like while the bottom was creamier. You can whip the pudding to have an even consistency, but leaving it in layers makes for an interesting dessert!

Either way, have fun comparing and consuming your delicious puddings!

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How do Peeps react to different temperatures? Make your own Peep slime!

Exploring the Mpemba Effect

Edible Gelatin Slime Version 2

Christmas Candy and Phase Changes

Sedimentary Rock Bars

Cranberry Slime

Cranberry Decoder

Edible Slime

Spud Mud

Cornstarch vs. gelatin: Make your own chocolate pudding

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