G5 What is Matter Made Of? – 03

When atoms join like this, they form compounds, and every compound is unique. Compounds also have a unique set of properties. This just means their properties are not the same as the atoms that make them up. The atoms they include have a specific ratio. The ratio of the atoms never changes. Think back to what you know about water molecules. Every molecule of water is the same as they all have two hydrogen and one oxygen atom. If the ratio changed, it would be a different substance. It would no longer be water. Are all substances that are compounds like water?

The next task has many steps for your group to complete. First, you place all the water molecules into the box. Next, you take more red blocks and join them together in groups of two, which will represent oxygen molecules. After you created the oxygen molecules, you take the green blocks and stick them together in groups of two. These represent nitrogen molecules. You still need to make one more molecule, so you take two red blocks and combine them with a black block. The black block represents carbon. This group represents a carbon dioxide (CO2) molecule. After all the new molecules are made, you place all of them in the box.

The task card asks, “What in the box is represented by the groups of blocks?” If you guessed air, you would be correct. Air is not a compound like the molecules you and your team created from the blocks. Air is not a molecule because the groups of atoms (molecules) are not joined together. Instead, they are just randomly intermixed. Many common substances are mixtures, such as wet sand or the trail mix in your lunch bag. In a mixture, properties of the individual substances are not changed.

Just as you get the last of the molecules in the box, the bell rings. The school day is over, at least as far as your core courses are concerned. Today’s after school band practice has been cancelled, so you are headed home. You cannot wait until Mom asks about your day. You will enjoy telling her all about playing with colored blocks all period. She always laughs when she hears you talk about Science class. She knows Mr. Harvey is an excellent teacher, and if you were playing with blocks, there was a much bigger purpose. Today you learned about atoms, elements, compounds, and mixtures. Sure, you just played with blocks.