Lenses help us see clearly by focusing light. They do this by bending light rays that pass through them. This bending is called refraction. It happens because of how the lens is shaped and what it is made of.

Types of Lenses:

1. Convex Lenses: These lenses are thicker in the middle. They bring light rays together to a single point.
2. Concave Lenses: These lenses are thinner in the middle. They spread light rays apart, creating a point that seems to come from behind the lens.

How It Works:

• When light rays that are parallel hit a lens, they change direction.
• The spot where the light rays meet or seem to spread out is called the focal point. The distance to this point is the lens's focal length ($f$), which depends on the lens's shape and material.

For example, a magnifying glass is a type of convex lens. It helps us see small details better by focusing light into a smaller space!