Salt Water vs Fresh Water
Describe and graph the amounts of salt water and fresh water in various reservoirs to provide evidence about the distribution of water on Earth
What a learner can do afterwards
- State that about 97% of Earth's water is salt water in the oceans
- Describe where fresh water is found: glaciers/ice caps, groundwater, rivers, lakes
- Create or interpret a graph showing the relative amounts of salt water vs fresh water
1 · Read
Earth looks like a blue marble from space because water covers most of it. But almost all of that water is salty ocean water. Only a tiny sliver is fresh water, the kind we drink and use.
That thin sliver of fresh water is not all in one place either. Most of it is frozen solid in glaciers and ice caps. The rest sits underground as groundwater, with just a small part in rivers and lakes.
Picture all of Earth's water poured into 100 cups. 97 of those cups would be salty ocean water. Only 3 cups would be fresh. Of those 3 cups, most is frozen ice, a smaller part is groundwater, and just a bit is in rivers and lakes.
When you read a graph like this, find the biggest bar first. The ocean bar is always the biggest one, because salt water makes up about 97% of all the water on Earth.
About 97% of Earth's water is salty ocean water, and only about 3% is fresh water, most of it frozen in glaciers and ice.
More to read
Salt Water and Freshwater Distribution on Earth
Almost all of Earth's water is salty ocean water. Only a tiny slice is fresh water we can drink or use to grow crops. Pictures and charts here show just how big that difference really is. On the graph, most of the space is salt water, and only a thin sliver is fresh water. That sliver splits again too: most fresh water is frozen in glaciers and ice caps, and the rest sits in groundwater, rivers, and lakes.
Lab 1: Where's the Water?
In this lab you use real numbers for how much water is on Earth and work out what share of it people can actually use. Oceans hold about 97% of all the water, leaving only about 3% as fresh water. Most of that fresh water is locked in glaciers and ice caps, so even less ends up in rivers, lakes, and groundwater. Working through the numbers shows why fresh water is such a precious resource.
Unit 1: Exploring the Reservoirs and Pathways and Methods to Measure the Hydrologic Cycle
Water on Earth moves between storage spots called reservoirs, like oceans, glaciers, groundwater, rivers, and lakes. This unit has you label a diagram of the water cycle and trace how water moves between those reservoirs. Seeing where fresh water is stored helps explain why oceans hold the vast majority of Earth's water while lakes and rivers only hold a small share.
Key points: Freshwater biomes
A biome is a community of plants and animals living together in a certain kind of place. Freshwater biomes are places where the water has little or no salt in it, like ponds, lakes, streams, and rivers. These freshwater spots are a vital source of drinking water for people, plants, and animals, and they are very different from the salty ocean, which holds far more water overall.
How to Desalinate Water: A Survival Guide
Desalination means taking the salt out of ocean water so it becomes fresh water people can drink. This guide shows how you could dig a hole near salt water and use the sun's heat to make a simple still that separates fresh water out. It's a good reminder that ocean water isn't the same as the fresh water we use every day, since removing that salt takes real effort.
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2 · Watch
به انگلیسیTake it off screen
Where it sits
Learn first
Optional connections
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Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
24 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.