a piece of glass or other transparent material shaped to refract light towards or away from a focus

(1) a point where many rays of light from an object meet (2) the process of refracting light rays so they meet

when light changes direction when it enters a new medium

the distance from the centre of a lens to where the lens focuses a distant object

Focusing light

Science

In the Waves unit, they will build on this knowledge to learn about the properties and propagation of transverse and longitudinal waves.

In the Sound, light and vision unit, pupils learnt how sound waves travel through different types of medium and are absorbed and reflected, how light is reflected off mirrors, and how the eye can see objects by the light they reflect.

This unit explores the transmission of light, including absorption, scattering, and reflection, and the use of the ray model in imaging, refraction, and lenses. It also covers energy transfer in various processes, using safe techniques, making accurate observations, and improving reliability.

Making images

The image can be rotated by turning the lens.

The image is always the same size as the object.

The image is always inverted compared with the object.

Which of the following statements about images made on a screen by a convex (converging) lens is correct?

closer to the lens than the focal distance

further from the lens than the focal distance

It depends on the distance between the lens and the object.

A pupil wants to use a lens to make an image of a bright object appear on a screen. Where should the pupil put the screen to see a clear image?

making the lens from a material that refracts light less

making the lens from a material that refracts light more

The more powerful a lens is, the shorter its focal length. Which of the following changes would make a lens more powerful?

The diagram shows a lens focusing light from a tree. Three of the rays are shown. At which of the labelled distances is an image formed?

All rays from one point on the object pass through the same part of the lens.

All rays from one point on the object arrive at the same point in the image.

Rays from all points on the object pass through each part of the lens.

Rays from all points on the object arrive at the same point in the image.

Which of the following happen when a lens forms an image of an object?

All parts of the lens refract light equally.

The thickest part of the lens refracts light most strongly.

The thinnest parts of the lens refract light most strongly.

The image shows a convex lens. Which of the following statements about the lens is correct?

The diagram shows light changing direction as it passes from one medium to another. This effect is called {{}}.

Each point on a luminous object emits light in all directions.

Each point on a luminous object emits light in one direction.

Each point on a non-luminous object reflects light in all directions.

Each point on a non-luminous object reflects light in one direction.

Which of the following statements are correct?

The light rays hitting the screen are virtual.

Light from every part of the Moon hits every part of the screen.

Each point on the screen is hit by light from only one point on the Moon.

A pupil holds up a screen to face the full Moon at night. Which of the following explains why an image of the Moon does not appear on the screen?

Transmission and refraction cannot happen together.

The ray meets the glass along the normal to the block’s surface.

The ray meets the glass at 90° to the normal to the block’s surface.

Refraction does not happen when light passes from air into a solid.

A light ray passes from air into a glass block, but it is not refracted. Which of the following statements can explain this?

The greater the angle between a ray and the normal, the more it is refracted.

The smaller the angle between a ray and the normal, the more it is refracted.

The angle between a ray and the normal doesn't affect how much it is refracted.

Light crosses a boundary from one material into another. Which of the following statements is correct?

Which of the following diagrams correctly shows light refracting through a rectangular block?

Introduction

What will you need for this lesson?

Are you ready to learn?

Equipment

Worksheet