pointing finger animation

Fill it up!

by Eric Muller

Math (Volume) and Earth Science

Type of Web activity:
Getting Information online

Materials / Software needed:
Web browser

Grade Level:
8 - 12

Time involved:
1 period

Created on:



The Web Science Workshop lessons were created in cooperation with the Exploratorium Teacher Institute .


This site developed and maintained by Deborah Hunt and Eric Muller .

Exploratorium logo

3601 Lyon St.
San Francisco, CA 94123

©2000 The Exploratorium

Imagine you could fill your school's classroom, auditorium or other enclosed space with a river of water. Use flow information from a local river or stream to figure out how long it would take to fill your space with water. This activity also helps students visualize a common unit of flow, the cfs or cubic feet per second.

1) Find the volume of the space to be filled with water. Measure the width, length and height of the space in feet and multiply. This is the number of cubic feet that would fit in the space.

2) Click on the United States Geologic Survey's Water resources page. This link will take you to real-time flow data. You may want to find a source of flowing water near your school

Click here to go to the USGS real-time water data.

3) Read the chart or graph on the real-time water data page. This is how many cubic feet of water pass by a gauging station each second.

4) To figure out how long it would take this amount of water, if diverted, to fill your enclosed space, divide the cubic feet of the space you measured by the cubic feet per second of water flow.

The Exploratorium is about
4,000,000 cubic feet in volume.

The Sacramento river empties into the San Francisco bay. The real-time data above (taken near the city of Sacramento on 8/6/00) says the flow of the Sacramento river is about 20,000 cfs.

4,000,000 3 ft

20,000 3 ft
per second

= 200 seconds

It would take 200 second or 3 1/3 minutes to totally fill the inside of the Exploratorium with water from the Sacramento River.

During a peak flow of 115,000 cfs like that of Jan. 3, 1997 it would only take about 35 seconds to fill the Exploratorium.

Back to Web Lessons Home Page