In this chapter we learned how to compare planets using numbers and mathematical formulas. Scientists often use maths in their work. Questions 1. How does using maths help scientists to describe the world around them? 2. In what other ways do you think scientists use maths?
Chapter Summary
1. 2.
3. 4. 5. 6. 7.
Scientists compare space objects in many different ways. Earth can be compared to other planets using calculations relating to mass, size and surface gravity. Relative mass is the mass of one object compared to another. Earth and other planets can be compared according to their composition. Mercury, Venus, Mars and Earth are known as the rocky planets. Jupiter, Saturn, Uranus and Neptune are known as the gas planets. Gravity gives weight to objects.
Questions and Exercises K C
Key Concepts Rewrite the following sentences in your copybook and fill in the blanks.
1. 2.
3. 4.
5. 6. 7. 8.
9. 10.
The relative mass of a planet is calculated by dividing its mass by the mass of ______________________ . The size of different planets can be compared using the measurement of their ______________________ . The force of gravity is strongest at the ______________________ of a planet. The gravity of different planets is compared using calculations of the force of gravity on the ______________________ of the planet. The inner planets of our solar system are composed mostly of __________________ . The outer planets of our solar system are composed of ______________________ . The mass of a planet depends on both its size and its ______________________ . Objects on the moon rise and fall more slowly than on Earth because the force of ______________________ is much less on the moon. The amount of time that it takes for Earth to make one complete rotation on its own axis is one ______________________ .
The amount of time that it takes for earth to complete one complete revolution of the sun is one ______________________ .
