5.2 - Distribution of Water on Earth
Enroll to start learning
You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Water Distribution Overview
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Today, we’re discussing the distribution of water on Earth. Can anyone tell me what percentage of water is found in oceans?
I think it's around 90%?
Close, but actually, about **97.5%** of Earth's water is saltwater in oceans. Now, can anyone tell me the significance of the remaining water?
Isn't that the freshwater we need for drinking and irrigation?
Exactly! Only **2.5%** of all water on Earth is freshwater. Let’s break it down further: approximately **68.7%** of this freshwater is locked in glaciers and ice caps. We can remember this as 'Ice = a Major Share of Fresh'.
What about groundwater then?
Good question! Groundwater makes up about **30.1%** of freshwater. Does anyone know where the remaining fraction of freshwater is found?
Is it in lakes and rivers?
Yes, precisely! About **1.2%** of freshwater is found in rivers and lakes. This emphasizes the importance of these bodies of water for both humans and ecosystems.
To recap, remember the percentages: Oceans are **97.5%**, Freshwater is **2.5%** with **68.7%** in ice, **30.1%** in groundwater, and **1.2%** in rivers and lakes.
Importance of Freshwater
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Why do you think the small fraction of freshwater is so important to us?
It’s crucial for drinking, right?
Absolutely! Freshwater is essential for drinking and agriculture—it's vital for our survival and food security. What might happen if we didn’t manage our freshwater resources wisely?
We might run out of clean water, which could lead to problems like famine or disease!
Exactly! Sustainable management is key. Remember, our water usage today affects future generations. What memory device can help us remember the significance of freshwater?
Maybe something like 'Freshwater Equals Future'?
Perfect! Let’s keep that in mind as we think about how to conserve and protect these vital resources.
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
The Earth's water distribution reveals that about 97.5% of water is saltwater in oceans, while only 2.5% is freshwater, with the majority locked in glaciers and icecaps, groundwater, and a small amount in surface waters like rivers and lakes.
Detailed
Distribution of Water on Earth
Water covers approximately 71% of the Earth’s surface, primarily as saltwater in oceans, which comprises 97.5% of total water resources. Only 2.5% of the Earth's water is freshwater, which is crucial for human consumption and various ecological functions. Among this freshwater:
- 68.7% is trapped in glaciers and icecaps.
- 30.1% is found as groundwater.
- A mere 1.2% resides in rivers and lakes, the primary sources of surface water for humans and wildlife.
This distribution emphasizes the limited availability of freshwater for human use and the importance of efficient management and conservation.
Youtube Videos
Audio Book
Dive deep into the subject with an immersive audiobook experience.
Overview of Water Distribution
Chapter 1 of 2
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
Source Percentage
Oceans (saltwater) ~97.5%
Freshwater ~2.5%
Detailed Explanation
The total amount of water on Earth is divided into two main categories: saltwater and freshwater. About 97.5% of the Earth's water is found in oceans, which is too salty for human consumption or most agricultural uses. Only approximately 2.5% of the Earth's water is freshwater, which is crucial for human life and activities.
Examples & Analogies
Think of the Earth's water as a large pie. If the pie represents all the water on Earth, then almost the entire pie – around 97 slices out of 100 – is filled with salty ocean water. The tiny sliver left, about 2.5 slices, is the freshwater we need for drinking, farming, and other uses.
Freshwater Sources Breakdown
Chapter 2 of 2
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
- Glaciers & Icecaps ~68.7% of freshwater
- Groundwater ~30.1% of freshwater
- Surface water (rivers, lakes) ~1.2% of freshwater
Detailed Explanation
Freshwater is primarily found in three forms: glaciers and ice caps, groundwater, and surface water. Glaciers and ice caps hold about 68.7% of the total freshwater. Groundwater, located beneath the Earth's surface, accounts for roughly 30.1%. Finally, surface water, which includes rivers and lakes, represents only about 1.2%. This shows how limited our easily accessible freshwater resources are.
Examples & Analogies
Imagine a large refrigerator filled with ice. Most of the ice (about 68.7%) is packed tightly in the back corner, which is hard to reach (this is like glaciers and icecaps). Some of the ice (30.1%) is in a bowl you can dip your hand into (this represents groundwater). However, the small cup of melted ice on the counter that you can drink from (1.2%) is very small compared to the rest, highlighting how limited our immediate supply of freshwater is.
Key Concepts
-
Water Distribution: Approximately 71% of Earth is covered by water, primarily in oceans.
-
Freshwater Availability: Only 2.5% of Earth's water is freshwater, critical for human use and ecological balance.
-
Storage of Freshwater: Most freshwater is held in glaciers (68.7%) and groundwater (30.1%), with a small amount in surface waters.
Examples & Applications
Example 1: The Great Lakes of North America represent one of the largest fresh surface water systems, crucial for drinking water in surrounding regions.
Example 2: The melting of glaciers due to climate change directly impacts freshwater availability downstream.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
Water in the sea, 97.5, Freshwater we must strive to keep alive.
Stories
Imagine a giant ice castle that holds the keys to drinking water—most is trapped in glaciers, while only a tiny stream flows in rivers.
Memory Tools
Remember 'GGS-R' for Freshwater distribution: Glaciers (68.7%), Groundwater (30.1%), Surface water (1.2%).
Acronyms
F-G-S (Freshwater, Groundwater, Surface) to remember freshwater distribution better!
Flash Cards
Glossary
- Saltwater
Water that contains a high concentration of dissolved salts, primarily found in oceans.
- Freshwater
Water with low concentrations of dissolved salts, necessary for drinking, agriculture, and industry.
- Glaciers
Large masses of ice formed from compacted snow, storing a significant portion of Earth's freshwater.
- Groundwater
Water located beneath the Earth's surface, stored in soil and rocks.
- Surface Water
Water that collects on the surface of the ground, including rivers, lakes, and ponds.
Reference links
Supplementary resources to enhance your learning experience.