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How high would the water rise if everyone on earth sat in the ocean? – Zahkaev and Viktor

It’s fun to think about fictitious questions, such as what happens if everyone on the planet goes swimming in the ocean at once. And using math, you can get pretty close to the real answer. Let’s start by considering a smaller version of the same question.

## Bathtub math

When you fill the bathtub to the top and jump in, you can see that it is a sticky cleaning. The water overflows because your body pushes the water out of the way – what is called displacement. The bottom and sides of the vat are solid, so the only direction water can go is up and down.

The amount of space an object (in this case you) occupies is called a volume. The amount of water that overflows from the bathtub is the same as the amount of your body.

Now consider a situation where the bathtub is only half full. When you dive, the volume of your body still pushes up the water. You can use some simple formulas to calculate how much the bathtub water level will rise.

Suppose the bathtub is a rectangular box. By considering the amount you add to the tub and the size of the area you are expanding this amount, you can see how much the water level will rise when you sit in the tub. The amount of water level rise is equal to the added volume divided by the area.

For a bathtub 5 feet long and 2 feet wide, the area is 10 square feet.

Now let’s calculate the volume. To simplify the calculation, let’s assume you are also a rectangular box like a bathtub. Let’s say you are about 4 feet high, 2 feet wide (left to right) and 1 foot deep (front to back). Your body volume can be 4 feet x 2 feet x 1 foot, or 8 cubic feet.

When you sit down, you add about half the volume of your body to the bathtub. This means that the height of the water level rise is equal to half the volume of your body divided by the area of the bathtub. Using the above estimate, this leads to a rise in water level, which is 4 cubic feet divided by 10 square feet. This is equivalent to about 5 inches. You will certainly notice it!

## Scale up

You can think of the sea as a huge bathtub.More than 70% of the earth’s surface is the sea, and in this bathtub Area of about 140 million square miles.. To figure out how much water will rise, you need to know how many people are sitting there and divide by this area.

Currently there are almost 8 billion people on earth.. Humans come in all sizes, from small babies to large adults. Let’s assume that the average size is 5 feet (a little larger than a child) and the average volume is 10 cubic feet. Only half of each person’s body is submerged when sitting, so the water level only increases by 5 cubic feet. For a total of 8 billion people, you can calculate 5 x 8 billion. That’s a whopping 40 billion cubic feet added to the ocean.

However, keep in mind that this volume extends over vast waters. Divide a volume of 40 billion cubic feet into 140 million square miles of sea using the same bathtub calculations as before.

answer? The total sea level rise is about 0.00012 inches, or less than 1/1000 inch.If everyone is completely submerged, this doubles the answer to 0.00024 inches, but this is still Human hair width..

The ocean turned out to be huge – and humans are just a drop in a bucket.

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*This article will be republished from conversation, A non-profit news site aimed at sharing ideas from academic experts. It was written by: Tony E. Won, Rochester Institute of Technology..*

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*Tony E. Wong does not work, consult, own shares, or receive funding for any company or organization that would benefit from this article.*