Measurement Session 1, Part A: Comparing Rocks

Session 1, Part A:
Comparing Rocks (15 minutes)

Measurement is used in all aspects of daily life, as well as in such fields as engineering, architecture, and medicine. We measure things every day. This morning you may have weighed yourself, poured two cups of water into the coffeemaker, checked the temperature outside to help you decide what to wear, cut enough gift wrap off the roll to wrap a present, decided on the size of a storage container for some leftover food, noted on your car's odometer how far you'd driven, monitored both your car's traveling speed and its gas gauge, and kept an eye on the time so that you wouldn't be late. All of the situations above are easily identifiable as measurement situations. Yet what is at the heart of all of these comparisons? In other words, in order to measure, what must we consider, and then what steps must we take? Note 2 To begin thinking about measurement, you will use, of all things, a rock.


Problem A1
Make a list of attributes that could be used to describe the rock.


Problem A2
Some of these attributes might be measurable, and some might not. How do we determine what we can measure?

If you are having difficulty sorting the attributes, consider which attributes can be quantified. For example, the texture of a rock (e.g., smooth, bumpy, rough) isn't quantifiable using any of the standard units we know; in contrast, the weight of the rock is quantifiable and can be measured in ounces or grams.

Another suggestion is to see what happens when you combine your object with another, similar object. If the attribute is measurable, then it will increase when the objects are combined. For example, when you combine two rocks, the texture won't increase or change in any way, but the weight certainly will. Close Tip

If you are having difficulty sorting the attributes, consider which attributes can be quantified. For example, the texture of a rock (e.g., smooth, bumpy, rough) isn't quantifiable using any of the standard units we know; in contrast, the weight of the rock is quantifiable and can be measured in ounces or grams. Another suggestion is to see what happens when you combine your object with another, similar object -- if the attribute is measurable, then it will increase when the objects are combined. For example, when you combine two rocks, the texture won't increase (or change in any way), but the weight certainly will.


Problem A3
If you were to compare different rocks using each of the measurable attributes you listed in Problem A1, what units would you use?


Problem A4
How could you measure these properties?

Think about what instruments, devices, or methods you might use. Close Tip

Part A adapted from Chapin, Suzanne, and Johnson, A. Math Matters: Understanding the Math You Teach, Grades K-6. p. 177. © 2000 by Math Solutions, Publications. Used with permission. All rights reserved.

Next > Part B: Which Rock Is the Largest?

Session 1: Index | Notes | Solutions | Video