# Hypsometric Curve - Practice Problems

Click on the hypsometric curve at left to open a larger version in a new window and use it to work through the problems below. I recommend you try each of these problems before looking at the solution - otherwise you won't know if you have gotten it or not. You can download a sheet with all the questions (Acrobat (PDF) 109kB Jul25 09) to help.

*Your answers may not be exactly the same as the ones given here because the graph is not precise.*Your answers should be within a half a kilometer or 5%.

## The Problems

**Problem 1: You want to create a submarine that allows you to can gain access to at least 80% of the Earth's surface, including the continents. How deep into the ocean can this submarine go? (80% of the Earth's surface is above what depth in the ocean)?**

**Problem 2: You've just invented a new alloy for a submarine that can withstand underwater pressures to a depth of 4.5 km below sea level. If this is the maximum depth to which an oceanographer interested in the sea floor could go, what percentage of the Earth's surface is inaccessible to your ocean floor study?**

*could*see 60% of the Earth's surface. However, we want to know how much is

*inaccessible*. So, we need to subtract 60% from 100%.

**100%-60% = 40%.**

So, 40% of the Earth's surface cannot be accessed by our oceanography team!

**Problem 3: Most plants cannot exist above 4 km above sea level. What percent of the Earth's surface is higher than this?**

**Problem 4: Most oceanic fish cannot live in depths below 4 km below sea level, and obviously can't live in areas that are above sea level. What percentage of the Earth can they occupy? that is, what percentage of the Earth's surface is between 4 kilometers below sea level and sea level?**

**18% of the Earth is below sea level but higher than 4 km below sea level**.

If this makes sense to you, go on to the quiz! If it doesn't, read on.

Think about if I want to find out what portion of my class is between 5'5" tall and 5'8" tall. I can determine how many people are shorter than 5'8" and then remove the ones that are below 5'5" and then I will be left only with the students that are between 5'5" and 5'8". This is exactly what we do in this case. We see how much of the Earth is below sea level (71%) and then remove the part that is too deep (deeper than 4 km below sea level - 53%) The remainder is in the range we want.

Go Back to the Hypsometric Curve Explanation

Go problems for you to do on your own at wamap