Light Energy

Back to: Basic Science Primary 3

Welcome to class.

Light is a form of energy which can be detected with our sense of light (eye). It is the visible part of electromagnetic spectrum. We are able to see distant sun, stars and moon with the aid of light which travels in a straight part. Energy associated with light is called LIGHT ENERGY. Without light, we cannot see. Light travels very fast in all directions.

Sources of light can be grouped into two, namely:

1. Natural source: natural source of light exists naturally and produces light without the help of man. It is God-made light. Examples include sun, stars, fire fly, lantern fly, etc. Our main source of natural light is the sun. the light that comes from the sun is referred to as a white light or sunlight. It should be noted that Light is not fire, but fire produces light while burning.

2. Artificial source: Light producing technologies are artificial light sources. Artificial light is light made by humans. They include torchlight, lamp, lantern, electric bulb, laser etc.

USES OF LIGHT ENERGY

1. To see: light from both natural and artificial sources can be used to see during the day and night.
2. To generate heat: light produces heat and the heat can be used to do work. Heat energy produces warmth.
3. Traffic light: light is used in traffic light to control traffic
4. To form image: reflection of light causes formation of image/. When the light from object falls on the mirror, the mirror will reflect the light to form image
5. Photosynthesis: this is the process whereby green plants produce their food from sunlight. Light energy is essential for photosynthesis because plants need energy to create glucose, which they store for later use as an energy source for cells.
6. We also use light energy in the form of globes to light up our houses at night.

 

EVALUATION

1. The sense organ used to detect light is ———————-
2. Group the following source of light under the natural and man-made headings: lantern, firefly, sun, torchlight, candle, stars, fire, electric bulb, lightning
3. Mention any three uses of light you know
4. The two sources of light are ——————- and ————————-

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