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:
A chemical reactionoccurs when substances are mixed together and are changed. Sometimes substances mix together and not much happens, at other times the results are pretty dramatic. Today we will look at a turbo charged chemical reaction. We will mix two substances together and add a catalyst, something to make the reaction happen faster.
What You Need:
Plastic Soda Bottle
Pour a cup of hydrogen peroxide in the liter soda bottle. Add a few drops of food coloring and a few drops of dish soap. In a separate bowl mix 1 teaspoon of yeast with two tablespoons of hot (not boiling – just use hot water from the faucet) water. Use the funnel to pour the yeast mixture into the mottle. Stand back!!
HINT: Do this one OUTSIDE!
HINT #2 If you want your geyser to spew more, use a plastic soda bottle that is smaller than a liter – a bottle that is smaller will have more foam shoot out of it.
Hydrogen peroxide has a lot of bubbles in it. If you let it sit long enough it will go “flat” – just like soda if you let it sit, the bubbles pop and eventually no carbination is left. When you add the yeast to the hydrogen peroxide the yeast makes this “going flat” happen super fast. The yeast breaks the hydrogen peroxide down into oxygen and water – a chemical reaction. The oxygen combines with the dish soap to make a whole lot of bubbles. In this experiment yeast is a catalyst. A catalyst speeds up a chemical reaction. Once the chemical reaction is over touch the foam – how does it feel? You might notice that the foam is a little bit warm. This chemical reaction is an exothermic one, that means that the chemical reaction produced a little heat.
Here are some websites and books that will give you more chemical reaction experiments to try:
Chemical Reaction – When a substances or substances is changed into a new substance. Exothermic – A chemical reaction that produces heat. Catalyst – Something that makes a chemical reaction happen faster.
Everything in the universe is made of teeny tiny particles called atoms. Some things are made up of just one kind of atom. A penny is made up entirely of copper atoms. Atoms can join together to make molecules. When a penny is exposed to oxygen in the air, the copper atoms of the penny and the oxygen atoms in the air combine. A chemical reactiontakes place that makes a molecule called copper oxide – that is the dirty stuff that you see on the penny. This “stuff” is often referred to as “tarnish.” When you soak the pennies in taco sauce, another chemical reactiontakes place. Try this experiment to watch this chemical reaction.
You Will Need:
Put some tarnished pennies in a small dish and pour taco sauce over them. Let the taco sauce sit for a few minutes and then wash the taco sauce off the pennies. How do the pennies look now? If you look at the ingredients in the taco sauce you will notice that the main ingredients are tomato paste, vinegar and salt. Which ingredient affected the tarnish on the pennies? To find out, you need to test different combinations of the ingredients. First, try to polish the pennies with just tomato paste, just salt and just vinegar. How do the pennies look? Then, try polishing the pennies in different combinations of the ingredients: tomato paste + salt, vinegar + salt and tomato paste + vinegar. Which combination worked best?
Here are some websites that will give you good directions for this experiment and an explanation of the chemical reaction that creates the tarnish and then takes it away again:
In today’s experiment you will be able to watch a chemical reaction. In this experiment vinegar (a substance) and baking soda (a substance) will mix together. When mixed together the molecules of the two substances will re-arrange, or change, to make new substances.
Vinegar has acetic acid in it. The chemical name for baking soda is sodium bicarbonate. When you mix the two together you get sodium acetate and water. You also get carbon dioxide, which is a gas. The bag puffs up because carbon dioxide is a gas and takes up a lot of space. Eventually the bag isn’t big enough to hold all that carbon dioxide gas so it explodes.
You Will Need:
Measuring Cups and Spoons
Snack size ziploc bag
Quart size ziploc bag
Measure one tablespoon of baking soda into a quart size ziploc bag. Measure 1/2 cup of vinegar into the snack size ziploc bag and zip the bag closed. Put the snack size ziploc bag full of vinegar into the quart size ziploc bag with the baking soda in it. Get as much air as possible out of the quart size bag before zipping it closed. Go outside! Stand in the middle of your yard. Grip the snack size ziploc bag from the outside of the quart size bag and pull it open. As soon as the vinegar starts to mix with the baking soda drop the bags into the grass and watch what happens.
If your bag inflates, but does not explode, try increasing the amount of baking soda and vinegar. If you do this, be sure to drop the bag quickly and take several steps away after you mix the two substances together – when the bag explodes it splashes vinegar everywhere…which does not feel good in your eyes. See the dog’s nose and eyes? Too close! And…it goes without saying to do this OUTSIDE.
Websites that give you good directions for making exploding ziplocs.
Vinegar is an acid. Eggshells are made of calcium carbonate. If you soak an egg in vinegar the eggshell will absorb the acid and break down, or dissolve. The calcium carbonate will become carbon dioxide gas. What is left is the soft tissue that lined the inside of the eggshell. Today’s experiment is similar to the Bouncing Egg experiment. For this one, before you soak the egg in vinegar, you blow out the egg like you are going to decorate an Easter egg. This time, the egg will be empty when it soaks.
What You Need:
Straight Pin or Tack
Use a stright pin or a tack to poke a small hole in both ends of raw a egg. Hold the egg over the sink and blow on one end of the egg so that the yolk and egg white drain out the hole on the other side. Once the egg is empty soak the remaining egg shell in vinegar for a week. How does the egg look when you are done soaking it? Hold the egg in your hand and fold it in half. Now let go. What does the egg do? Toss the folded egg gently back and forth between your two hands. Now what does it do?
The vinegar dissolvs the hard shell of the egg. What you have left is the soft inner membrane of the egg. It LOOKS hard and still has an egg shape but it is soft, that’s why you can fold it. When you gently toss the egg back and forth btween your hands air enters through the two holes at either end of the egg. The egg blows back up, just like a balloon.
Here are some books websites that will help you understands acids and how they behave and the strange example of the folding eggshell:
Google Preview:Naked Eggs and Flying Potatoes (How to Make a Folding Egg page 89-91)
Words to Know:
Acid – A chemical that is often sour tasting and corrosive. It dissolves some things. Dissolve – When a solid comes apart and spreads out into a liquid…like kool aid in water. Calcium - One of the most common minerals found in animals bodies. It makes up bones, teeth, and eggshells. Absorb – To soak up…like a sponge in water.