Let's get out the rulers and measuring tapes, and, of course, pencil and paper for our list.

We'll measure everything we can. There are some pieces of wood we can measure, we can measure the desk tops, the doors to the classroom, our textbooks; with our long tape measure, we can even measure our classroom!

We need to know all the dimensions of the things we measure; not just length and width, but height and depth, as well, so we'll know how thick these things are.

We can measure the length and width of our door, for example, and then, multiply the width times the length, and we will know the square footage of the door! Same with our classroom. Measure the length and the width, multiply the answers, and we have square feet!

So what? What good does it do to know the square footage of a room? What if we wanted to order carpet for our room? What if there were laws about how many people could be allowed in one classroom of a certain size? (There are those kinds of laws, you know.) There are several reasons to know the size of a room.

Let's see how we do on some things that are not rectangular. We can try to measure a piece of a jigsaw puzzle, a marble, perhaps a jack. How on earth do we measure something that is round? How do we measure a round cake pan?

What is diameter? What is radius? What is Pi? We have to find out.

How else can things be measured? Weight is a measurement of size; that's one way (that's one weigh!) to measure things.

We can't weigh our door, but we can weigh our marble. Also, we can weigh the blocks of wood we measured. If we have a block of wood of the same kind as our door, and maybe even the same thickness, we could:

1. weigh the block;
2. measure the length and width of the block;
3. multiply the length times the width to get square inches;
4. divide that result into the square inches of the door;
5. multiply that result by the weight of the block; and
6. maybe we'd know how much the door weighs. Maybe not--
we'll have to try it and see what happens.

It would also be interesting to measure a piece of metal and then weigh it, and compare that weight to the weight of a piece of wood that is the same size, and see if the weights are different.

We could even make a list of the sizes of the stuff we measured, and then their weights. We could even see the difference between a pound of feathers and a pound of wood!