The Sun

All of Earth’s energy can be traced back to the sun.


D1.11 Abstract of waves

Solar energy travels to Earth by electromagnetic waves and is then used in many different ways. About a quarter of the solar energy received by Earth is reflected back into space. Of the solar energy that is absorbed by Earth, a small portion gets converted to food energy through photosynthesis and the rest of it is converted to thermal energy. Remember from Unit C,  thermal energy is heat or the energy a substance has due to the kinetic energy (movement) of its particles. The more kinetic energy the particles have, the warmer the substance is.

Different regions on Earth receive different amounts of solar energy due to their location on Earth and the angle Earth sits at. We will study this in more detail in Lesson 3.
Recall from Unit C that there are many different forms of energy on Earth. All of these forms of energy can be traced back to the sun. The sun’s energy that reaches Earth is known as radiant energy. This type of energy is transmitted as electromagnetic waves. This means that the energy travels from one point to another through almost any material in waves that we cannot see.

D1.13 Temperatures rise

  Digging Deeper

D1.12 The electromagnetic spectrum

There are many forms of electromagnetic waves, including infrared radiation, microwaves, X-rays, ultraviolet rays, and more. All of these forms put together create the electromagnetic spectrum. Go to the following link for more information about this spectrum.

Learn More

Did You Know?

D1.14 Solar panel farm

The sun provides 100 000 times more energy than all other sources of energy combined! That is a lot of energy.


  Read This

Please read pages 356 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on how solar energy is used when it reaches Earth. Remember, if you have any questions or do not understand something, ask your teacher!
 

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. How is solar energy used once it reaches Earth?

    Most of the solar energy is converted to thermal energy once it reaches Earth. A small amount of it is converted to food energy through photosynthesis.

  2. What is the source of all energy on Earth?

    The sun!