Raven draws a long bar on the whiteboard and splits it into 100 tiny boxes.
"Pretend this bar holds all of Earth's water," she says. "Each box is one percent."
Rocket picks up the blue marker. "I will color the oceans," he says, and keeps coloring and coloring.
Nova blinks. "Stop at about 96 and a half," she says. "How much is left for fresh water?"
Rocket stares at the last few boxes. "That is all?" he says. "Hardly any!"
Scientists at the U.S. Geological Survey measure where Earth's water is.
The oceans hold about 96.5 percent of all of Earth's water.
Only about 2.5 percent of Earth's water is fresh water.
The rest is about 1 percent. It is salty water in other places, mostly underground.
| Kind of water | About how much of Earth's water |
|---|---|
| Ocean water (salty) | 96.5 percent |
| Fresh water | 2.5 percent |
| Other salty water | About 1 percent |
Percent means out of 100.
If 96.5 percent of Earth's water is ocean, then 96.5 out of every 100 cups are ocean water.
Only 2.5 cups out of 100 are fresh.
| Statement | True or false? |
|---|---|
| The oceans hold about 96.5 percent of Earth's water. | ? |
| About half of Earth's water is fresh. | ? |
| About 1 percent of Earth's water is other salty water. | ? |
| Most of Earth's water is salty. | ? |
You read and used real data today. Tomorrow you will build a model you can hold.