What Is Chemistry Chemistry is the study of the materials that everything is made from Chemists study what different substances can do what they are made of and if and how they might change Knowing all about chemistry is very useful Doctors use chemistry to develop medicine Farmers use it to help crops grow Chefs use chemistry to create great food Chemistry is also fun Try the experiments in this book and find out about chemistry for yourself Detective Work To find out exactly what a mystery substance is chemists do tests and ask questions They might try to find out what temperature a liquid boils or freezes at or see if a substance dissolves in water Chemists might test to see if a substance is just one thing or a mixture of things Maybe they want to find out if it changes when it is heated or if it changes back when it is cooled again 4
Setting Up Your Backyard Laboratory Find an outside space that you can use to do these experiments Some of them are pretty messy Remember to check with whomever owns the space that it is OK to do your experiments there You may want to find a picnic table to work on You should be able to find most of the things you will need around your home or yard You may need to buy some small items so check the You Will Need section before you start a project BE SCIENTIFIC Be a scientist Think of an idea that you want to prove or disprove Then do an experiment to test the idea To create a fair test try to just change one thing at a time Repeat your experiment to check your result wasn’t a fluke Take notes Was your idea correct Can you draw a conclusion The experiments STAYING SAFE chosen because they are Science experiments can be dangerous Ask be careful in this book have been specially but you must still Wear any fun and relatively safe all Follow an adult to help you suggested protective clothing warnings and be careful 5
Minty Geysers What happens when you add a packet of mints to a bottle of cola It gets messy Make sure you try this experiment in a big open space The experiment works best with diet cola as it has slightly different ingredients from regular cola Make sure the cola is not past its sell-by date too 1 2 YOU WILL NEED a packet of Mentos a large 2-liter plastic bottle of diet cola a sheet of paper some tape ADULT HELP NEEDED Roll some paper tightly around the packet of mints Cut away any excess paper Secure the cylinder using a small piece of tape Check that the cylinder fits inside the top of the bottle It needs to be able to easily slide in and out 6
Place the bottle in an open space Stand well back Ask an adult to unscrew the lid and quickly push the mints through the cylinder into the bottle Then run 5 3 4 Unwrap the mints Place them in the cylinder Hold a hand over the bottom of the cylinder to keep the mints from falling out WHAT’S HAPPENING Soda has carbon dioxide gas in it It is the carbon dioxide which makes it fizz When you drop the Mentos into the bottle tiny bubbles form around each of the small dents on the sugar coating As the mints sink the gas bubbles push the soda up with an incredible force 7
