How can we figure out what size carrying case we need for the telescope? I have a brand new telescope, but I don’t have a case for it. My friend is at the store and wants to know what size I need, but I don’t have a ruler. How can I figure out what size to get?

In this lesson you will learn how to measure by using smaller, equally sized objects.

You already know how compare the size of an object to another object, like a block, a paper clip, and even your finger. These are objects you can use as non-standard units for measuring length.

One “Common Misunderstanding” is thinking that you can measure things using objects that aren’t the same size, like this… So it isn’t really accurate to say that this frame is 4 paper clips long, because some of the paper clips are large and some are small.

Objects are the same size Ends are touching No overlapping In a straight line Let’s use crayons to find the length of the longer side of this math journal. We’ll use brand new crayons so they’ll all be the same size. The objects have to be the same size, have the ends touching with no space between them and no overlapping, and they have to be in a straight line. So the length of the long side of the notebook is about 3 crayons.

Same size Ends touching No overlapping Straight line Now let’s try it with paper clips. Objects the same size? Check. Ends are touching? Check. No overlapping? Check. In a straight line? Check. 1-2-3-4-5-6-7. It’s 7 paper clips long.

We can use the same steps to measure the ladybug picture with blocks We can use the same steps to measure the ladybug picture with blocks. 1-2-3-4-5 blocks long.

The smaller the object, the more you will need. The larger the object, the fewer you will need. No matter what you are measuring, the smaller the object you are using as your unit of measure, the more of them you will need. 8 paper clips. The larger the object you are using, the fewer you will need. 3 crayons, or less than two big feet!

Back to my telescope. How can we decide which carrying case will be the best fit? The crayons are longer than the paper clips. It takes 9 paper clips to measure the same length that is measured by 4 crayons. So if my friend at the store can find a crayon or a paper clip, she can find the perfect case for me!

In this lesson you learned how to measure by using smaller, equally sized objects.