You're building something out of blocks, and you just need one more to finish it. Oh no. Where is it? All you need is a red block about this big to fit right there and you just can't find it. Sigh. Atoms are no different. In order to make different things, they have to have the right blocks that are the right color (or kind) and the right shape. How can we make sure that you can always find what you are looking for while building? Let's sort the world's atoms into boxes.
Oh look, a red one. We'll put that in the red blocks box. Say that fast three ties.
So, let's talk blocks. As you know, blocks can come in all different shapes and sizes, colors and materials. Big, small, red, blue, plastic, wood. When talking about the single things that make up our world, we are talking about one kind of block. An element
is something that is made out of only one kind of atom. That does not sound like very much fun. Lucky for us, the world has a lot of blocks to play with.
There are many kinds of blocks. Just look around you at all the different colors and shapes. A property
tells us what an element is like or what it can do. If we were to put the blocks of the world away, these are the different boxes they would go in. Take silver, for example. It's cold, shiny, and heavy. That's an expensive block. Do not lose that one.
Silver, so shiny when new. Does this go in the jewelry box? I don't think so.
We have got boxes and you have got hands. Start putting those blocks away. How will you choose which blocks will go into which boxes? It's easy, right? We will put the red ones in one box, the blue ones in another, the heavy ones in another, and the big ones in another. A physical property
is the color, weight, or size of something. Do not drop that lead block on your foot. That would hurt.
Lead will either weigh you down or help you build bigger muscles.
We have a problem. We left the boxes out. The blocks were rained on, heated up, pushed around by the wind. Now the blocks are changing. They do not even look the same. That one is a different color. That one broke into a lot of smaller boxes. Elements do that sometimes. Sorry I did not warn you about that. A chemical property
is how one atom acts with another. If we heat up one block a lot it might change how it works with other blocks. This could also happen if they get wet, if we pour acid on them or. . . any number of other things, really. I guess we had better find some new boxes.
The statue of liberty is covered in copper. The copper is green because it reacted with the oxygen in the air.
The world's elements can be separated into different boxes. You have to be careful, though. You can separate some elements into different types just by looking at their color or size, or feeling how heavy they are. You won't be able to separate others until they get really hot or wet and transform into something completely new. I know, I know, you'd change too if you got too hot or wet. But elements do a lot more than get mad or giggle.
Ducksters. "Elements" Ducksters, 2009. <http://www.ducksters.com/science/elements.php>
Chem 4 Kids. "Chemical Versus Physical Changes" Chem 4 Kids, 2012. <http://www.chem4kids.com/files/matter_chemphys.html>