Pour 1/2 cup of milk into a bowl. Put the bowl in the microwave for 1 minute. Check the bowl – if the milk looks lumpy you are done. If the milk does not look lumpy yet microwave it again for 25 seconds. Check it again. Repeat until the milk has formed lumps. After the lumps appear add 1 teaspoon vinegar to the bowl and let the bowl sit for 1 hour. After 1 hour is up pour the liquid off the milk lumps. Smash the lumps of milk together like play dough. You can make it any shape you want. If you leave it alone it will turn hard. If you want to save it keep it in a sealed container.
When the milk and vinegar (an acid), mix together a chemical reaction takes place. A substance called Casein forms. Casein is a very long molecule that bends like plastic – that’s why your lump of milk is pliable and bendy until it dries out and turns hard. Casein is also found in cheese…which is made from milk. Does this give you a clue as to how cheese is made?
Science Project Idea:
Make 3 different bowls of milk play dough. Use the same amount of milk in each bowl but use different amounts of vinegar in each one. OR use the same amount of vinegar in each bowl AND the same amount of milk…but use three different kinds of milk: skim, 2% and whole. Guess which bowl will make the best milk play dough. Why do you think so?
Here are some websites and books that will help you understand the science behind milk play dough:
When you cut open an apple it doesn’t look good for very long does it? After even just a few minutes an apple can start to look brown inside. The apple turns brown because you cut the apple open and exposed what’s inside the apple skin to the air, which has oxygen in it. Oxidation is a chemical reaction that takes place when a substance combines with oxygen. When apple flesh combines with oxygen it turns brown. The browning of the apple is called oxidation.
Another kind of oxidation you probably have seen is rust. When metal comes in contact with oxygen a chemical reaction takes place – oxidation. In this case the result of oxidation is rust.
What You Need:
3 Apple Slices
1 Orange Slice
1/2 Cup Orange Juice
3 Small Plates
Carmel Dip and the Rest of the Apple Slices (optional)
Put one apple slice on each plate. One apple slice leave alone. Pour the orange juice over one apple slice, pour orange juice over one apple slice and lay the orange slice on top of the last apple slice. Wait a couple hours. How do the apple slices compare? Which one is the most brown?
Here are some websites and books to help you understand oxidation:
Science Rocks Oxidation Station (pages 32-33)
Kitchen Science Experiments: Hey, Apple! Orange You Glad to See Me? (pages 51-52)
Oxidation – A chemical reaction that happens when a substance combines with oxygen.
Sound is vibrations that move through the air or through liquids or solids. The sounds we usually hear are vibrations that move through the air. Your voice is the vibration of your vocal chords. The tiny bones inside your ears pick up sound vibrations in the air and send those messages to your brain. You can actually see sound…if you know how to look.
What You Need:
2 Large Metal Pans
Anything That Makes Noise!
Stretch a large piece of plastic wrap over a bowl and pull it tight on all the edges. Sprinkle salt on top of the plastic wrap. Now blow a whistle or clap your hands or bang two objects together – how does the salt behave? Now clean the salt off and try putting drops of water on top of the plastic wrap. Can you make the water move with sound?
Science Experiment Idea:
Try different noisemakers to see which one will move the salt the most. Make marks on the platic wrap with a sharpie to help you see how much the salt moves. Try different volumes of sound both loud and soft as well as high and low pitches. For example, can you hum and make the salt move? Can you scream and make the salt move? How about a kazoo? A whistle? Which kind of sound do you think will move the salt the most? After testing, were you right?
Microscopes and magnifying glasses are used to look at objects that are very, very small. The microscope and the magnifying glass magnifies the obeject so that a person can see it. To magnify means to make bigger. A microscope or a magnifying glass can magnify an object 10 times or 100 times or 1,000 times or more.
Every object on earth has potential energy. That means it COULD move even if it isn’t right now. When an object IS moving it has kinetic energy.
In today’s demonstration you are going to store energy in a spring. That spring will have the potential to move, but it won’t move until you let it move. The catapult you make is going to transfer energy from the spring to a marshmallow. The marshmallow will have potential energy until the catapult releases, then the marshmallow will have kinetic energy as it flies through the air.
You Will Need:
Here are some websites and books that will help you understand energy:
Gadgets and Gizmos Chapter on Energy “Energize” (pages 111-136). Marshmallow Catapult (Pages 120-122).
Science Experiments That Fly and Move (pages 12-13) Marshmallow Shooter
Words to Know:
Energy – the ability to move things or do work; a force acting through a distance. Potential Energy – Stored energy. Kinetic Energy – The energy of motion. Catapult – A device used to throw an object…like a slingshot or a medieval catapult the knights at a castle might use.