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Learn About Reactions & Polymers
There are all sorts of reactions going on around us each day. A
chemical reaction is something that happens when two or more substances come into contact with each other. One substance combines with another and creates a whole ew 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 yeast science project, 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:
- Digestion - whenever you eat, your body uses many different and very complex chemical reactions to break down the food and convert it into energy and other things that your body needs! (To learn more about digestion, check out this page.)
- Combustion - fire is another type of chemical reaction, called combustion. It needs oxygen, fuel, and heat in order to exist and the reaction creates light, heat, and smoke.
- Oxidation - rust is a chemical reaction that you might see happening somewhere around you. Sometimes a reddish-colored layer will form on iron or steel (types of metal) when the metal reacts with oxygen in the air. Most iron and steel is treated to prevent it from rusting, though, so you usually only find rust on old pieces of metal that have been in contact with a lot of water and have gradually rusted over several years. When an apple turns brown after you bite into it, that is oxidation, too. An enzyme in the flesh part of the apple reacts with oxygen from the air and turns the apple brown.
In the slime experiment, you learned what a polymer is - 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:
- Plastic is one of the most common polymers. There are lots of different types of plastics that have very different properties - some plastics are flexible and can be bent (like a plastic bag or a toothpaste tube) and some are very solid and would split or crack if you tried to bend them (like a plastic plate or a CD).
- Fabric such as rayon, nylon, and polyester that are used for making clothes such as shirts, sweaters, and socks.
- Natural polymers - one of the most important natural polymers is DNA, the protein in your cells that makes you who you are! Some other things that come from naturally-occurring polymers are cotton, silk, rubber, paper, and leather. Rubber comes from a natural source - a plant! Before it can be used though, it has to be processed.
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
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.