Author: Maddie Van Beek

It’s officially fall! Thursday, September 22nd marked day one of a new season, and you may have already felt it in the weather. Fargo has been characteristically chilly this past weekend! With the fall season comes new colors in your surroundings. You’ll notice once-green, lush plants either dry out and turn brown, OR as they dry, they may transform into a vibrant yellow, red, or orange! How do you know what color the leaves will change? There’s actually a way to find out, and that’s what we will learn about today! Before we get going on our activity, let’s learn more about why leaves change color in the first place. 


Why are leaves green? Chlorophyll is a chemical in plants that helps photosynthesis occur. Photosynthesis is the process in which plants are able to absorb water and carbon dioxide and turn it into food. This could not happen without the help of sunlight! 


Here is a diagram of how photosynthesis occurs: ​

YOU SHOULD KNOW:

• What makes leaves green? 
• Describe what photosynthesis does? 
• What do leaves need for photosynthesis to occur? 
• What purpose does chlorophyll serve? 
• How do leaves change color? 

Now that you know the science behind the beautiful fall scenery, let’s move on to our activity! Your job is to determine the future colors of the leaves. Let’s get started! 
 
YOU WILL NEED:

• Fresh, green leaves (make sure they haven’t begun to change color and aren’t crunchy)
• Bowl
• Hot water
• Rubbing alcohol
• Coffee filter
• Scissors
• Clear glass or jar
• Plastic wrap
• Spoon or fork

Here’s what to do! 

1. Gather some fresh green leaves from your yard or somewhere outside. Make sure the leaves are all green. Your leaves should NOT be dry or crunchy. 
2. Bring your leaves inside and rip them into tiny pieces. 
3. Put the leaf pieces into the clear glass or jar. Pour rubbing alcohol over the leaf shreds until they are completely covered. 
4. Use a spoon or fork to mash the leaf bits up and stir them in with the rubbing alcohol. You may see the rubbing alcohol begin to turn green. 
5. Place plastic wrap over the mouth of the jar and secure it. 
6. Heat up a bowl of hot water. Carefully place the jar in the center of the bowl. The level of the hot water should be just above the level of the rubbing alcohol. 
7. Leave the jar in the bowl of hot water for at least 30 minutes. Swish the jar around every once in a while the stir up the leaves. You should notice the rubbing alcohol turning a very dark green. 
8. After 30-60min, you should be ready to move on! Cut a strip of coffee filter (or paper towel) so you have a long rectangle. 
9. Dangle the coffee filter strip into the jar of rubbing alcohol so one end of the strip is touching the surface of the rubbing alcohol and the other end rests over the edge of the jar. 
10. Now, just wait patiently. The rubbing alcohol will travel up the coffee filter strip and carry the green pigment with it. As the rubbing alcohol travels upwards, the once all-green pigment will separate into more than one color. You’ll see green (the chlorophyll) and another color such as yellow, orange, or red appear. 
11. Gather leaves from other types of trees and repeat the process to see if you can get other colors to appear! 

Image and video credits, in order of appearance:


Jongleur100, 2007. Country lane. File uploaded from Wikimedia Commons on 9/25/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/1/18/Country_lane.jpg/800px-Country_lane.jpg File in the Public Domain. 

At09kg, 2011. Photosynthesis. Uploaded from Wikimedia Commons on 9/25/2016.
https://upload.wikimedia.org/wikipedia/commons/thumb/d/db/Photosynthesis.gif/800px-Photosynthesis.gif
File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license. No changes were made. 
​

References
https://en.wikipedia.org/wiki/Autumn_leaf_color
https://en.wikipedia.org/wiki/Chlorophyll
https://en.wikipedia.org/wiki/Photosynthesis
http://www.howweelearn.com/science-experiments-for-kids/

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: ​

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

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:

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:

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

Author: Maddie Van Beek

Energy: What you get when you eat a whole bag of Skittles and six Mountain Dews? Not exactly. What IS energy? Let's find out! 

Ok, so what are the two main types of energy? Put them into your own words!

• Potential

• Kinetic

So remember, energy is never actually LOST--it is just transferred or converted into other TYPES of energy. To go a little further into what potential and kinetic energy actually are, let’s watch this video! It may be an old cartoon, but the reality of energy has not changed! ​

Examples of potential and kinetic energy: 

Dropping a ball (or anything, really!)

Stretching a rubber band or shooting an arrow: The farther I stretch the rubber band, the more potential energy it has. When I let go of the rubber band, the potential energy immediately transfers into kinetic energy. This concept is very similar to archery. The stretched bow is full of potential energy; when the string is released, the bow's potential energy transfers into the arrow's kinetic energy. 

A roller coaster: As the roller coaster car climbs upwards, it is gaining potential energy. At the top of the peak, potential energy is at its height. As soon as the car drops downwards, all that gained potential energy is converted to kinetic energy. Kinetic energy is at an all-time high at the very bottom of the drop, and then it begins to convert back to potential energy. Kinetic energy increases at the same rate that potential energy decreases. They are INVERSES of one another.

Still confused? Think again of a roller coaster. If the roller coaster starts at the top with 100 Joules (Joules are the units used to measure both kinetic and potential energy) of potential energy, the point at the end of drop would have 100 Joules of kinetic energy, because that’s when the roller coaster would be at its fastest. A moment later, when the roller coaster starts going up again, that kinetic energy goes down, and what increases? That’s right, potential energy. 

Take a moment to think of a few more examples. When have you seen potential energy? When have you seen kinetic energy? 

Let’s demonstrate this! 

YOU WILL NEED:

• Basketball
• Tennis ball
• Tape measure or yard stick

Hypothesize: Does the height from which a ball is dropped affect how high a ball will bounce? 

Here's what to do!

1. Use the tape measure or yard stick to measure three feet up from the ground. 
2. Lift the basketball to the three foot mark. 
3. Drop the ball and pay attention to how it bounced. Record the height. Do this three times and find the average height.
4. Now, measure five feet up from the ground. Repeat steps 1-3. 
5. Did the height from which the ball was dropped affect the height that the ball bounced? Explain. 

Now, we will do the same with a tennis ball.

Hypothesize: Does the size of the ball affect how high it will bounce? 

Repeat steps 1-5 with the tennis ball. 

Did you get the same results? Explain.

Let's try something new! First, hold the basketball. Next, hold the tennis ball in place directly on top of the basketball. Drop both balls at the same exact time and watch what happens! 

You should have seen the basketball hit the ground and the tennis ball hit the basketball, which then sends the tennis ball flying! When does the tennis ball bounce higher--on its own, or when it hits the basketball? Record your observations. 

Why did the basketball cause the tennis ball to come bouncing back up? Would this work the same way if you dropped the balls in the opposite order? If you’re not sure, try it out and see what happens!

Based on your previous observations, which ball has more kinetic energy, the tennis ball or the basketball? Why do you think this is? 


Force

When you dropped the tennis ball and the basketball, you saw two forces at work. First, both the tennis ball and the basketball had a force acting upon them--gravity. Second, when the basketball hit the ground, the energy from the impact was transferred to the tennis ball, creating contact force. 

What is force, you ask? Force is the push or pull of an object that happens when an interaction between two objects occur. Picture two vehicles crashing into each head on at the same speed. If one vehicle is a semi-truck and one is a Mini Cooper, which vehicle will have more force enacted upon it? Well, think of the tennis ball as the Mini Cooper and the basketball as the semi-truck. That’s just a start on understanding force and Newton’s Laws, but that's enough for now! 

Until next time--May the force be with you! 

References:
​
https://en.wikipedia.org/wiki/Forms_of_energy

http://www.sciencekids.co.nz/experiments/bouncingballs.html

http://www.physicsclassroom.com/class/newtlaws/Lesson-2/The-Meaning-of-Force

http://www.eschooltoday.com/energy/kinds-of-energy/what-is-kinetic-energy.html

Image and Video Credits, in order of appearance:

The Science Asylum, 2013. What is Energy REALLY?! Uploaded from YouTube on 9/4/2016. https://youtu.be/jCrOtF7T4HE

cassiw2, 2009. The story of potential and kinetic energy. Uploaded from YouTube on 9/4/2016. https://youtu.be/7K4V0NvUxRg

​Bartz & Maggs, 2007. Bouncing ball strobe edit. Uploaded from Wikimedia Commons on 9/4/2016. 
https://upload.wikimedia.org/wikipedia/commons/thumb/3/3c/Bouncing_ball_strobe_edit.jpg/1024px-Bouncing_ball_strobe_edit.jpg File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license. No changes were made. 

Psalter, 1324. Longbowmen. Uploaded from Wikimedia Commons on 9/4/2016.
https://upload.wikimedia.org/wikipedia/commons/a/a7/Longbowmen.jpg File released into the Public Domain. 

BrandonR, 2005. Wooden roller coaster txgi. 
https://upload.wikimedia.org/wikipedia/commons/3/30/Wooden_roller_coaster_txgi.jpg
​Uploaded from Wikimedia Commons on 9/4/2016. File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license. No changes were made. 

Utchay Endre, 2008. May the force be with you. https://youtu.be/vSJNeXrCbE4 Uploaded from YouTube on 9/4/2016.