Solar Energy

Over time, it has been proved that students, who practice with worksheets all through the year, eventually do well in their end-of-year-exams. This is especially true for STEM subjects.

Study of science is important for  children to understand the world better, be it physical science, life science, environmental science or earth science. With science learning, children can comprehend whatever is happening around them, right from the formation of a rainbow to digestion of the food they eat.

This Grade 7 Worksheet aims at strengthening students’ concepts in Earth Science. The topic assessed is ‘Solar Energy’. This worksheet includes fill in the blanks, definitions and diagram based questions that make it fun and interesting.

The Sun

The sun is a huge shining star in the solar system which is about one hundred million times the size of Earth. Suppose Earth was a mustard seed, the sun would be roughly the size of a basketball. It is again just an assumption of how big it is than the Earth. Truth is its unimaginable coz no one ever got very close to it ever. It is in the centre of the Milky Way galaxy, our galaxy and holds all the planets in its position.

Every planet takes its own time period to rotate around its axis and so they have different lengths of days. For example Venus is the slowest of all; it takes 243 days to complete one rotation.

We say that the Sun rises in the east and sets in the west but that is just a way of saying. It doesn’t mean that the sun is moving. The Sun is constant and all the planets of the Milky Way galaxy revolve around it. It is a vital source of energy to all the planets but since life exists on Earth we know how essential it is to us.

The Earth’s rotation about its axis causes day and night. One half of the Earth has daylight, the other half has nights. As the Earth spins we move from light to shadow and back to light again over the course of one day (24 hours).

During the night we cannot see the Sun move across the sky, but when we look carefully we notice that the stars move across the sky, just like the Sun does.

Earth’s Rotation

It takes the Earth 24 hours to make one complete turn (called a rotation) on its axis, so an Earth day is 24 hours long.

Earth’s Revolution

The Earth revolves around the Sun in a circle, and it takes 365 ¼ days for one revolution to complete. The Earth revolves around the Sun it also rotates (spins) on its axis at the same time. The earth’s revolution around the sun causes the seasons.

What is solar energy and how is it used?

Plants prepare their own food with the help of chlorophyll in the presence of sunlight. The Sun’s energy is processed and stored in the form of food so that it can be used later. In photosynthesis the energy from the Sun is used to change carbon dioxide and water into carbohydrates (for example cellulose, starch or glucose). The carbohydrates are stored in fruits, leaves, wood or bark. When we eat a plant product, for example an apple, our bodies are able to utilize the energy stored in the apple in the form of carbohydrates, vitamins etc. In the same way animals, for example cows, use the Sun’s energy when they eat the grass.

We all living beings directly or indirectly depend on plants on photosynthesis for our energy. Earlier we learnt about energy transfer between producers, for example grass, and consumer: example a lion. Plants play a vital role in life on Earth as they form the basis of food chains. Without plants, life on Earth would not be possible. As we depend on plants so does plants depend on the Sun for survival and would die without its energy which allows them to photosynthesize.

Check Point

1. What is the approximate surface temperature of the Sun?
2. What is nuclear fusion?
3. Why is the sun very important?
4. What do you mean by the Earth’s Rotation?
5. What do you mean by the Earth’s Revolution?
6. What are the different forms of energy?

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