You can measure a number of attributes of rocks -- for example, surface area, volume, and weight. Which of these attributes should you use to determine the largest rock? Let's collect measurements of each type, looking at surface area first. Note 3
The area enclosing a three-dimensional or solid object is referred to as the surface area. Imagine that a thin skin covers all the surfaces of your rock. How would you determine the size of this skin?
For this activity, you'll need your rock, a sheet of tinfoil large enough to wrap around the rock, and pieces of grid paper with units of 1 cm2, 0.5 cm2, and 0.25 cm2. You can print this grid paper (PDF - be sure to print this document full scale) if you wish.
Before you begin measuring, estimate the surface area of your rock. (Later, you can compare your estimate with the approximate surface area you've measured.)