Have you ever wondered why some things fizz, bubble, foam, or change shapes or colors when you mix them together? Here you will learn the science behind some very cool reactions - and you can even try them out at home!
Up, Up, and Away!
Well, your balloon might not quite fly away in this experiment, but you can make it inflate by creating a reaction in a bottle.
The warm water made the yeast 'wake up' and it immediately started to have a chemical reaction with the sugar. Two substances, yeast and sugar, reacted to each other and together they made a new substance - a gas called carbon dioxide. Carbon dioxide is the same gas that makes soda pop fizzy, and one of the many gases in the air we breathe in and out. The carbon dioxide from the reaction filled up all the space in the plastic bottle and kept rising to fill up the balloon. At first, the yeast should have looked puffy or bubbly on the surface of the water as it was beginning to react with the warmth of the water. Then, you probably noticed that the balloon was standing straight up instead of being flopped over the mouth of the bottle! That was the first sign that the yeast was reacting with the sugar and that carbon dioxide gas was being made. Soon after that, the balloon should have started to inflate. Since the balloon was made of stretchy rubber (and you helped stretch it out), it kept expanding to hold the carbon dioxide, the same as it would if you were to blow it up with your mouth. When you breathe out (or exhale), your lungs push carbon dioxide out, along with a few other gases, which is how you are able to blow up a balloon.
Now that you know how it works, you might want to try the experiment with other types of sugar mixtures. What do you think would happen if you used your favorite soda or juice instead of the sugar water?
So, if yeast and sugar react this way in a bottle, what happens when you bake with them? Well, the same thing happens, it just looks a little different. Bread and many other baked goods are made from yeast. The yeast reacts with the sugar in the dough and releases carbon dioxide, which creates tiny air bubbles that pop and leave air pockets as the dough bakes into bread. You can get a closer look at the air pockets left behind in a slice of bread.
The slime you just made is called a polymer (say: PAUL-UH-MER). The word polymer means 'many parts.' White glue is one type of polymer. When you mixed water with the white glue, the glue formed long chains of thousands of little molecules that you couldn't see until you added the Borax solution. The Borax had a reaction with the glue - it linked all those chains together, which made the whole mixture thicker and turned it into a blob of slime, a different type of polymer!
There are lots different types of polymers, including plastic, rubber, Jell-O, glue, camera film, materials such as nylon, and even natural fibers from wood and cotton. This polymer has properties of a solid and a liquid at once. Compare your polymer to a solid object - a piece of chocolate. Break the chocolate in half. Try quickly breaking the wad of slime in half. Did you get a clean break similar to the way the chocolate broke? To see how it is also like a liquid, try slowly stretching the blob out between your hands. You can't do that with a solid piece of chocolate! The polymer is showing its liquid properties when you stretch it slowly. Now set the slime back into the bowl you made it in and watch what happens. It should flatten out to fill the bottom of the bowl, similar to a liquid like pancake batter would do.
Chemical reaction- when two or more substances come into contact and form a new substance.
Carbon Dioxide- a gas that is in the air on earth, but in very small amounts. Plants need it in order to live; they use it to covert sunlight into food. Humans breathe out carbon dioxide when we exhale. In chemistry, it is abbreviated CO2, which means that is has one carbon atom and two oxygen atoms.
Oxygen - a gas that is very abundant on earth and that humans and most animals breathe to stay alive. It does not have any color, smell, or taste.
Polymer - the word 'poly' means many, so a polymer is a long chain of molecules that gives a substance the ability to stretch and be very flexible.
Plants need carbon dioxide. They use a reaction called photosynthesis to combine carbon dioxide from the air with energy from sunlight to make food.
Rubber is a type of natural polymer that is used for many things. However, natural rubber gets too soft when it gets hot and it becomes very hard when it gets cold. In 1839, a man named Charles Goodyear discovered by accident how to make rubber resist temperature changes. His discovery made rubber useful for more things like tires and shoes. Sometimes mistakes in science lead to amazing discoveries!
Paper money in the United States is made out of two natural polymers - cotton and silk!
Why are chemists great at solving problems? (Answer: Because they have all the solutions.)
How do scientists freshen their breath? (Answer: With experi-mints!)
Way Cool Websites
Check this site out for more carbon dioxide experiments, like how to inflate a balloon using baking soda instead of yeast.
Watch this video of a chemical reaction that produced some incredible foam!
There are all sorts of reactions going on around us each day. A chemical reactionis something that happens when two or more substances come into contact with each other. One substance combines with another and creates a whole new substance that wasn't there when the reaction started. Different types of reactions can happen depending on the substances that are put together. Sometimes a little of the original ingredients will be left over after the reaction, and sometimes more than one new substance will be formed in the reaction. In the first science project in this newsletter, the yeast reacted with the warm sugar-water and produced carbon dioxide, which you could see filling up the balloon.
There are also many other types of chemical reactions that take place around us and even inside of us every day! Can you think of any examples? Here are a few to get you started:
In the second experiment, you learned what a polymeris - a long chain of hundreds or thousands of tiny molecules.The slime you made is an interesting type of polymer that can act like a solid or a liquid depending on how it is handled. There are lots and lots of polymers in our world. Some are natural and some are made by humans, or synthetic. Here are a few examples of polymers:
For more information and project ideas for teaching kids about polymers, check out our Polymer and Slime Experiments page.
Use this worksheet as a fun activity to reinforce the basic chemistry concepts of chemical reactions and polymers. Kids can color the page and then determine whether each picture is a polymer, a reaction, or neither.