This picture inspires a wonderful volume project, and can easily have scientific notation and proportions integrated into the project as well.

(1) Have students calculate the volume of the Earth.

(2) Research the amount of water that’s on the Earth (about 326 million trillion gallons according to science.howstuffworks.com)

(3) Have students calculate what size sphere would hold that volume of water

(4) Either with a computer drawing program or just on a piece of paper, have students use proportions to show the size of the Earth compared to the sphere that would hold the world’s water.

** The same thing can be done with air (atmosphere), though I couldn’t find a specific number as to the exact volume of air. But considering the atmosphere extends (very roughly) out to about 300 km (there’s more atmosphere, I’m sure, but the density of the molecules would be very negligible), simply take the radius of the Earth (6,378.1 km) to figure out the volume of the Earth, then draw another sphere around the Earth that has a radius of 6,678.1 (radius of Earth + 300) and calculate the volume of that sphere, and the difference would be the volume of the atmosphere … albeit a very rough estimation. Students shouldn’t be told this, of course!

Here’s a site with more information about the Amount of Water in/on/above the Earth.