Question

Estimate the mass of water on the earth. The density of water is 1000 \text{ kg}\cdot\text{ m}^{-3}1000 kg⋅ m
−3
. Here are some approximations you can use:

Compared with the oceans, lakes and rivers are tiny. Clouds have very low density. There is (still) lots of ice in the polar regions, but much less area than in the oceans. So neglect all except the oceans, which cover roughly 2/3 of the earth.

Looking at charts of the oceans, we see that the depth is typically several thousand m (and a serious search tells me the average depth is 4700 m). The radius of the earth is about 6000 km. The surface area of a sphere is 4\pi R^24πR
2
.

This is an order or magnitude question. Express your answer in kg, as a power of 10. For example, if you think the answer is 10^410
4
kg, enter 10^4

Answer 1

Explanation:

Here are some Estimate the mass of water on the earth. The density of water is 1000 kg. m approximations you can use: Compared with the oceans, lakes and rivers are tiny. Clouds have very low density. There is (still) lots of ice in the polar regions, but much less area than in the oceans. So neglect all except the oceans, which cover roughly 2/3 of the earth. Looking at charts of the oceans, we see that the depth is typically several thousand m (and a serious search tells me the average depth is 4700 m). The radius of the earth is about 6000 km. The surface area of a sphere is 47 R2. This is an order or magnitude question. Express your answer in kg, as a power of 10. For example, if you think the answer is 104 kg, enter 10^4