I am not a chemist, but I will be explaining chemistry to some third-graders. I want to give the example of how different things can be made of the same parts, but arranged differently. My "real world" example is a car and a motorcycle. The car has an engine and four wheels, but we can create a different vehicle with an engine and only two wheels: we get a motorcycle. What two elements
Y create two common molecules with the formulae
I was hoping to use carbon and hydrogen because the children have already heard me use those words, and
CH4 is a gas that will make them laugh when I tell them where it comes from. But the only
CH2 molecule that I could find is this which is too complicated and unfamiliar to explain. I would prefer molecules composed of the common elements hydrogen, oxygen, carbon. I would like to avoid molecules of elements that are commonly found in their elemental state such as gold, iron, or silver as at this stage I want to reinforce the idea that we cannot see molecules with the unaided eye. I might introduce the idea that a molecule (and macromaterial) can be composed of a single element later, if this lesson goes well.