# Workout: Archimedes' Principle

## Read

Read the web page Archimedes' Principle.

## Launch

To give you some practice on working with fluid pressures, go to the PhET simulation Fluid Pressure and Flow to perform a few tasks.

## Set up

Chose the tab "Pressure" and turn on the Ruler. Drain the tank by pulling the blue drain tab under the tank to the right. Your screen should look like the figure below.

## Answer these questions

1. Use the pressure meter to measure the pressure (air pressure) at the top and bottom of the tank. The pressure increases as you go down. Explain why.

2. Can you calculate the density of the air that the program assumes from this data? If so, put the value in kg/m^{3}and explain how you calculated it. If not, write "no" and explain what additional information you would need.

3. Now use the tab on the faucet handle to fill the tank. How much is the pressure difference between the top of the tank (just above the water) and the bottom (just above the floor)?

4. Now select the middle of the three possible tank arrangements. Look at the pressure at a depth of 1, 2, and 3 meters at various places in the tank. Does the pressure depend on how much water is above you? How much water is below you? Or what? At any point in the tank, how could you predict what the pressure would be?

Joe Redish, Fall 2017

Last Modified: February 12, 2019