Units, Measurement and Estimation
How many measurements did you make before school started this morning? Probably more than you realize! Perhaps you figured out how many times you can press snooze on your alarm before you’re running late to how much cereal and milk you need to fill your breakfast bowl. The cups, pounds, inches, and miles that we are so familiar with here in the United States are much less common throughout the rest of the world. As we learned, most countries (and nearly all scientists!) use the metric system.
During our activity, we estimated the length, mass, and volume of various objects using metric units. Then students made a second estimation for each object using calibration guides, which greatly improved the precision and accuracy of their estimates. Students worked through stations making metric estimates of items such as the length of a piece of rope and the weight of a pint size bottle of water. For the second round of stations, we gave the students some hints to improve their estimates. They came up with some creative ways to measure the rope, for example, measuring it against their bodies or using the tiles on the floor to guess the length. After the stations, we talked about how to use conversion factors when converting from one unit to another. Ask your student how the density of water can be used to help find the weight of a bottle of water if the volume is known.