Section 1: Water is found in many places on Earth; it occurs in many forms.

Key Ideas     Unit Checklist

  Unit E: Section 1 – Introduction


Figure E.S.1.1 – Earth is sometimes called the “blue planet” or the “water planet”.

Figure E.S.1.2 – Earth’s atmosphere contains large amounts of water.


Figure E.S.1.3 – 70 percent of Earth’s surface is covered in oceans.
The Water Planet

Earth is the only known planet that supports a wide variety of living things. Earth is uniquely able to support life because it contains large amounts of liquid water. All living things need water in their cells. Photosynthetic organisms need water to make their own food. Earth’s atmosphere and oceans collected water before the first single-celled organisms developed, around 3.8 billion years ago.

A few other planets and moons in the solar system contain some water. Earth’s neighbouring planet Mars contains frozen water on its surface, as well as some water in its atmosphere. Because water is present on Mars, scientists are searching to discover if living things ever existed on Mars.

  Words to Think About:

Check out the word cloud below. It pictures the important words that you are going to learn in this section. Watch for these words, and combinations of these words, as you read. When you see them highlighted, you can click on them to learn more about what the word means. You can also visit the course glossary and read definitions for all of these words.

 
Lessons in This Section

Lesson E1: Water on Earth
Key Question – Where is water found on Earth?

Lesson E2: Substances in Water
Key Question – What different types of substances are found in water?

Lesson E3: Water Purification
Key Question – How do humans make water safe to drink?
Reading and Materials for This Section

Science in Action 8
Reading: Pages 334–347

Materials Lists for Unit:
Master List of all materials
Materials organized by lesson and activity

 Watch More

Where Did Earth's Water Come From?

Watch this video to learn more about how water originally collected on Earth.

 

 

  Try It! 

Water Bodies

Try this experiment to observe the presence of water in the human body. 

Materials: 
  • Glass cup
  • Fridge


Instructions:

  1. Put a glass cup into a cold fridge for one hour.

  2. Take the glass cup out of the fridge.

  3. Breathe out through your mouth onto the side of the cold glass cup.

  4. Look at the glass cup. What do you observe?


Questions: 

Think about the following question very carefully. Then, type or write your answer. When you have your answer, click the question for feedback.

In this experiment, you observed that breathing on a cold glass formed small water drops on the glass. This experiment showed that humans breathe out water. Water is a product of cellular respiration in our bodies.