Why and How do we measure? Length

People measure things in different ways. This week Pre-K friends learned that some things are long and some things are short. Friends learned that to know the length of the thing means to know how long thing is. To measure things people use rulers or measuring tape, but in times when they are not available we can use something else-  shoes, our feet, or paper clips. When we use something beside the ruler we call it nonstandard unit. As you see above, Nosson uses nonstandard units-  small paper clips to measure the length of his shoe. There are some rules which we follow when we use nonstandard measurements.  We can use only one item in a time to measure things. For example, in the class we have big and small paper clips. Measuring friends used only one kind of paper clips.  Other rule is we can't leave any space between nonstandard units in order to get accurate measurements.

We decided to measure the length of our room with nonstandard units. We measured it with body rulers - Sholomo and Yonni.  Our room is 8 1/2 Shlomo's body ruler long but 7 1/2 Yonni's body ruler long. Why? Friends said that is because Yonni is taller that Shlomo.