Fast Facts
A cubic mile of water equals more than one trillion gallons.
Each day, 280 cubic miles (450 cubic km) of water evaporate or transpire into the atmosphere.
If all the water in the atmosphere fell as precipitation at once, the Earth would be covered with only about 1 inch (2.5 cm) of water.
The 48 contiguous United States receives a total volume of about 4 cubic miles (6.4 cubic km) of precipitation each day.
If all of the world's water was poured on the United States, it would cover the land to a depth of 107 miles (145 km).
Yet, the ocean is so vast that if the earth were a smooth shell, the ocean would cover the planet the depth of which would be 8,200 ft. (2,500 m).
Fast Facts
A cubic mile of water equals more than one trillion gallons.
Each day, 280 cubic miles (450 cubic km) of water evaporate or transpire into the atmosphere.
If all the water in the atmosphere fell as precipitation at once, the Earth would be covered with only about 1 inch (2.5 cm) of water.
The 48 contiguous United States receives a total volume of about 4 cubic miles (6.4 cubic km) of precipitation each day.
If all of the world's water was poured on the United States, it would cover the land to a depth of 107 miles (145 km).
Yet, the ocean is so vast that if the earth were a smooth shell, the ocean would cover the planet the depth of which would be 8,200 ft. (2,500 m).
Overview
Water is the most abundant and important substance on Earth. It is essential to life and is a major component of all living things. There are approximately 336,000,000,000,000,000,000 gallons of water on the earth, existing in three states; solid, liquid and gas.
Water is contained in the oceans, icecaps & glaciers, ground water, fresh-water lakes, inland seas, soil moisture, atmosphere, and rivers. The students will discover the different water ratios in the earth's total water supply.
| TOTAL TIME | 20 minutes |
|---|---|
| SUPPLIES | Eight (8) 1000 ml beakers, Plastic cup, Eyedropper |
| PRINTED/AV MATERIAL | None |
| TEACHER PREPARATION | None |
| SAFETY FOCUS | Flash Flood Safety |
Procedure
- Label beaker #1 "oceans" and fill it with 1000 ml of water.
- Label the following beakers: beaker #2 "glaciers & icecaps", beaker #3 "groundwater", beaker #4 "fresh-water lakes", beaker #5 "inland seas", beaker #6 "soil moisture", beaker #7 "atmosphere", and beaker #8 "rivers".
- Inform the students to assume the earth's total water supply has been reduced to 1000 ml as indicated in beaker #1.
- Ask the students how much water must be transferred from beaker #1 into each of the remaining beakers representing the portion of water in each section. Write their estimates on the chalk board.
- Transfer the following amounts of water FROM beaker #1 to each of the remaining beakers.
- Glaciers & icecaps - 21.4 ml
- Groundwater - 6.1 ml
- Fresh-water lakes - 0.09 ml (∼2 drops)
- Inland seas - 0.08 ml (1½ drops)
- Soil moisture - 0.05 ml (one drop)
- Atmosphere - 0.01 ml (0.2 drop)
- Rivers - 0.001 ml (0.02 drop)
Obviously, the last two, atmosphere and river, will be nearly impossible to obtain. So, by adding no drops will help in the students understanding of how little water is in those two locations.
Discussion
The students will be surprised how little water is found in each of the remaining beakers. The vast majority of water is found in the oceans; approximately 97.2%. The following are the percentages for each water source:
| Water Source | Water volume (cubic miles) |
Total Water (%) |
|---|---|---|
| Oceans | 317,000,000 | 97.24 |
| Glaciers & icecaps | 7,000,000 | 2.14 |
| Groundwater | 2,000,000 | 0.61 |
| Fresh-water lakes | 30,000 | 0.009 |
| Inland seas | 25,000 | 0.008 |
| Soil moisture | 16,000 | 0.005 |
| Atmosphere | 3,100 | 0.001 |
| Rivers | 300 | 0.0001 |
| Total water volume | 326,000,000 | 100.0000 |
Despite the overabundance of rain we often receive, the atmosphere contains very little of the earth's total water supply. This demonstration can lead into water conservation awareness and teaching students to think about ways of saving our drinking water. For more info visit EPA Water Sense
Building a Weather-Ready Nation
The amount of moisture in the atmosphere is indicated by the dew point temperature. As the dew point increases, so does the potential for the amount of rain produced by a thunderstorm increase. Stationary or slow-moving thunderstorms produce heavy rain over small areas and increase the risk of flash flooding.
Hilly and mountainous areas are especially vulnerable to flash floods, where steep terrain and narrow canyons can funnel heavy rain into small creeks and dry ravines, turning them into raging walls of water. Even on the prairie, normally-dry draws and low spots can fill with rushing water during very heavy rain.
Take time to develop a flood safety plan-for home, work, or school, and wherever you spend time during the summer. The National Weather Service has additional information about flood safety and a brochure "Floods and Flash Floods...The Awesome Power".
Preparations at home and work:
- Determine if you are in a flood-prone area. If you are, know where to go if the water starts to rise. Have an escape route if you have to leave quickly.
- Make a safety kit containing: A flashlight and extra batteries, battery-powered weather radio receiver and commercial radio, extra food and water, first-aid supplies, canned food and a can opener, water (three gallons per person), extra clothing, and bedding. Don't forget special items for family members such as diapers, baby formula, prescription or essential medications, extra eyeglasses or hearing aids, and pet supplies.
- Know how and when to shut off utilities: Electricity, gas, and water.
- Seek sources for obtaining local warning information such as from cable TV or the NOAA Weather Radio.
Fast Facts
A cubic mile of water equals more than one trillion gallons.
Each day, 280 cubic miles (450 cubic km) of water evaporate or transpire into the atmosphere.
If all the water in the atmosphere fell as precipitation at once, the Earth would be covered with only about 1 inch (2.5 cm) of water.
The 48 contiguous United States receives a total volume of about 4 cubic miles (6.4 cubic km) of precipitation each day.
If all of the world's water was poured on the United States, it would cover the land to a depth of 107 miles (145 km).
Yet, the ocean is so vast that if the earth were a smooth shell, the ocean would cover the planet the depth of which would be 8,200 ft. (2,500 m).