This article explains light energy for kids in an easy-to-understand manner. Read on to find out more about light, its sources, colors, transparency of materials, shadows, and so on.

What is light?

Light is a form of energy that our eyes can see. It is made up of billions of tiny particles known as photons. It is not matter because it has no mass and does not occupy space. It also travels in a straight line.

It travels at a very fast speed -- 299,792,458 metres per seconds to be exact. This is so fast that it appears instantaneous to our eyes. In contrast, the speed of sound is 340.29 meters per second, which is a lot slower. This is why during a thunderstorm, we see lightning first and hear thunder after a few seconds.

Sources of light

Light sources are things that produce light on their own. Light can come from natural sources or man-made sources. Natural sources of light are stars, such as the Sun which is also our most important source of light. Other natural sources include lightning, volcanoes, and even from animals such as fireflies. Artificial or man-made include electric bulbs and lamps.

Is the moon a source of light?

Light Energy for Kids - MoonlightCredit:

At night during a full moon, you may notice that the moon seems to glow on its own. But is the moon really a light source? It turns that out that most of the moonlight is actually sunlight that is reflected off the surface of the moon. Some of the moonlight also comes from other stars and the Earth. Because the moon reflects light and does not produce any of its own, it is not a light source.

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A moon in your room

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Our eyes see only when light enters them. We see objects when they either produce or reflect light.

For example, in a dark room, you would not be able to see anything. However, if a lamp in the room were switched on, you would be able to see other objects in the room because these objects reflect the light from the lamp into your eyes.


Although we see objects when they reflect light, not all objects form an image like a mirror does. Objects where images are not formed have a rough surface that reflects light unevenly (the rays bounce off in all directions). In contrast, a mirror has a very smooth surface which causes light to bounce off it at the same angle that it hits the mirror, thus forming an image.


White light is actually made up of a combination of different colors of light. The colors are red, orange, yellow, green, blue, indigo, violet. Did you notice that these are also the colors of the rainbow?

We see objects in different colors because they reflect some light and absorb others. The color that we see if the color that the object reflects. For example, a red apple reflects the color red while absorbing all the other colors. A white object reflects most or all of the light and a black object in contrast reflects little or none and absorbs most or all of it.

Creating a rainbow

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You may notice that rainbows tend to form after a rainy day. This is because sunlight passes through raindrops and splits into many different rays.

You can also create a rainbow by shining white light through a prism.


Different materials allow different amounts of light to pass through. A transparent material allows most light to pass through it. A translucent material allows some to pass through it. An opaque material does not allow any light to pass through it.

  • Examples of transparent materials are glass, water, and clear plastic.
  • Examples of translucent materials are thin cloths, tinted glass, and thin paper.
  • Examples of opaque materials are wood, rubber and metal.

Light and shadow

Shadows are cast when objects block out light. Shadows are cast on the opposite side of a light source and they form a shape that is similar to that of the object.

Different shadows can be cast by objects of different materials. Objects that are transparent cast a faint shadow or no shadow at all. Objects that are translucent cast a faint shadow. Objects that are opaque cast a dark shadow.

How do you change the size of a shadow?

The size of a shadow can be changed by moving the object nearer or further away from the light source. A bigger shadow is formed when the object is nearer to the source. A smaller shadow is formed when the object is further away from the source.

Shadows and the time of the day

Have you noticed that the shadow you form changes in size and position throughout the day As the sun moves to different positions throughout the day, the shadow you form is cast on its opposite side. Hence, the shadow changes in size and position during different times of the day.

Shadows are the longest during morning and evening and the shortest during the noon.

Using shadow to tell the time

A long time ago, people used a sundial to tell the time. A sundial is a device is put out in the sun and casts a shadow onto a marked surface. The shadow moves onto different positions during different times of the day and this allows people to tell the time without a clock.

SundialCredit: Public domain
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