Because we are going to study various changes in our environment, we must know the difference between a physical and a chemical change. They should understand that in a physical change nothing new is formed. There are a variety of ways to reinforce this for the student. One way is to heat water to it’s boiling point and then have it condense on a cooler object. The student will then realize that a change in state is a physical change.
Chemical changes result in something new being formed. A good way to demonstrate this is to use iron filings and sulfur. Mix the two together and use a magnet to separate the mixture. Remix the sulfur and iron filings, heat and repeat trying to separate the two by using the magnet. This shows that the iron and sulfur have combined to create a new substance iron sulfide. This reaction is an example of a chemical change.