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Students learn to measure the length of objects using non-standard units like paperclips or blocks.
Have you ever wondered if your favorite toy is longer than your lunchbox, but you don't have a ruler? What if you could use your own shoes or even paperclips to find out?
When we want to know which object is bigger, we look at its length. Length is how long something is from one end to the other. To compare two things, like a pencil and a crayon, we must follow one very important rule: Line up the ends! If we don't start them at the same spot, we won't know the truth. We call the object that sticks out further the longer one. The other one is shorter. If they are the same, we say they are the same length.
1. Place a pencil on the table. 2. Place a crayon right next to it. 3. Move them so both of their bottom ends touch the same straight line. 4. Look at the top. The pencil goes higher than the crayon. 5. This means the pencil is longer than the crayon.
Quick Check
If you want to see which of two jump ropes is longer, what is the first thing you should do with their ends?
Answer
You should line up the ends so they start at the same place.
What if you want to know exactly how long something is? You can use non-standard units! These are just everyday objects like paperclips, blocks, or even your footsteps. To measure correctly, you must lay your tools in a straight line from one end to the other. You must make sure there are no gaps (empty spaces) and no overlaps (one tool sitting on top of another). Then, you just count how many tools you used! If a book is blocks long, and a phone is blocks long, we know the book is longer.
1. Get a marker and some small square blocks. 2. Start at the very edge of the marker. 3. Lay block down. Lay the next block so it touches the first one perfectly. 4. Keep going until you reach the other end of the marker. 5. Count them: . The marker is blocks long!
Quick Check
If you measure a spoon and leave big spaces between your paperclips, will your answer be correct?
Answer
No, because you must have no gaps to get the right measurement.
Sometimes we have more than two things to compare. We can put them in order. We can go from shortest to longest or longest to shortest. To do this, we compare them two at a time. If a glue stick is shorter than a book, and a paperclip is shorter than the glue stick, then the paperclip is the shortest of all! This is like a puzzle where we find the smallest, the middle-sized, and the biggest.
1. You have a Scissors ( units), a Crayon ( units), and a Paperclip ( units). 2. Compare them: is smaller than , and is smaller than . 3. Order from shortest to longest: Paperclip Crayon Scissors. 4. Order from longest to shortest: Scissors Crayon Paperclip.
To compare two sticks fairly, how should you place them?
If a toy car is blocks long and a toy bus is blocks long, which is shorter?
When measuring with paperclips, it is okay to let the paperclips overlap each other.
Review Tomorrow
Tomorrow, try to remember the two 'Golden Rules' of measuring: No Gaps and No Overlaps!
Practice Activity
Find three things in your kitchen (like a spoon, a napkin, and a cup). Try to guess which is longest, then line them up to check!