Discovering Light and How It Behaves!

 

What is light?

Light is produced when one form of energy is changed to light energy. For example, in a light bulb, electrical energy is changed to light energy. In a fire, chemical energy stored in the fuel is changed to light energy.

When light rays hit an object, they are either reflected, transmitted, or absorbed:

-          reflected means the light is bounced back by the object (foe example: a mirror)

-          transmitted means the light passes through the object (light passes through the glass of the window)

-          absorbed means the light is taken in by the object. Most objects absorb some colors of light and reflect others. Only clear objects transmit the light that hits them.

What is reflection?

A person can see an image of themselves when they look at a mirror. Light rays bounce off their face, hit the mirror, and bounce straight back to their eyes. The bouncing back of light from a surface is called reflection.

Light rays bounce off a mirror at the same angle they hit the mirror. If a person looks at a mirror at an angle, they will not see their face reflected. They will see the reflection of something else. This example of reflection is similar to a ball bouncing off a wall. If a person throws a ball straight at a wall, the ball bounces back to them. If they throw the ball at an angle, the ball bounces at the same angle to the other side.

What is refraction?

When light moves through one material and into another material, the light rays can bend. The bending of light as it moves from one material into another is called refraction.

When you put a pencil in a glass full of water, it appears to be broken. But why? The answer is the refraction of light. Due to the refraction of light, a pencil appears to be broken when putting in a glass of water.

Refraction is the bending of light when it travels from one medium to another medium. When light crosses the boundary between both of the mediums, then there is a deviation that occurs in the path of the light ray. This phenomenon is known as refraction.

When the light travels through the air and passes into the water, the speed of light decreases, and its direction also changes.

The formation of a rainbow, mirage, prism, twinkling stars, swimming pool that looks shallow than its actual depth are some of the perfect examples of refraction.

 

Lenses:

A lens is a curved piece of clear glass or plastic that bends light rays. Lenses are used in microscopes to make objects look larger. They are used in telescopes to make distant objects look closer.

Lenses in eyeglasses help people see objects more clearly. There are two kinds of lenses used in eyeglasses. They are convex lenses and concave lenses.

Convex lens: A convex lens is thicker at the centre and gets thinner as we move towards the edges. It is a converging lens that makes light rays converge as they pass through. As a result, when we see an object through a convex lens, it looks larger than its actual size. Someone who is farsighted can see distant objects clearly, but close objects look blurry.

Concave lens A concave lens is thin in the middle and thicker at the edges. It is shaped like a cave. It is a diverging lens that makes light rays spread out as they pass through. As a result, when we see an object through a concave lens, it looks smaller than its actual size. Someone who is nearsighted can see close objects clearly, but distant objects look blurry.