Watery Mission

This activity involves counting the sections to work out what fraction of each planet is water. The students may count sections to find either the number of sections that are land or the number of sections that are water. Make sure that the students compare water with the total area and not water with land.
See Answers and Teachers’ Notes: Measurement, Figure It Out, Level 3, pages 14–15 for ways to help the students count the irregular-shaped land masses.
Some students may question whether the sections are equal, as they are not squares. This could lead to an extension activity in which the students look at the different ways in which the 3-D world is shown on a 2-D map. The students could discuss which projections are more accurate and why.

Answers to Activities

a. Planet Pascal
b. By working out how many of the 20 sections on each planet are land, you find
out that approximately 7/20 of Planet Pascal is land, leaving approximately 13/20, or just under 2/3, as water. You could use a number line to decide
which planet’s water is closest to 2/3.