1. Optics

2. Starter
Can you complete this diagram? What is this shape of lens called?
Principal axis

3. Learning Objectives Know key terms related to convex lenses.
Know the effect of a convex lens on: a diverging beam of light, a parallel beam of light.
Know how a camera and projector produce an image.
Know how to find the size of an image.

4. Success criteria
Describe the effect of a convex lens on: a diverging beam of light, a parallel beam of light having done an experiment. (Grade C)
Explain the difference between a camera and projector. (Grade C)
Use scale diagrams to find image sizes. (Grade A)

5. Convex lenses
Convex lenses are also called converging lenses, because they bring light rays together to a focal point.
The focal length is measured from the centre of the lens to the focal point.
Measure the focal length on your diagram.

6. Thicker Lenses
Thicker lenses bend light more, and so are more powerful – they have shorter focal lengths.
What about the eye?

7. Uses of convex lenses Convex lenses are used in: Telescopes Cameras
The thing which is allowing you to read this!
They use convex lenses to focus what is called a real image.

8. Real Images Projectors and cameras both produce real images.
Light from the object actually reaches a screen or film.

9. Ray Diagrams

11. Learning Objectives Know key terms related to convex lenses.
Know the effect of a convex lens on: a diverging beam of light, a parallel beam of light.
Know how a camera and projector produce an image.
Know how to find the size of an image.

12. Success criteria
Describe the effect of a convex lens on: a diverging beam of light, a parallel beam of light having done an experiment. (Grade C)
Explain the difference between a camera and projector. (Grade C)
Use scale diagrams to find image sizes. (Grade A)

13. Plenary Which diagram represents a camera?
ANSWERS: A B
Which diagram represents a camera?
Which diagram represents a slide projector?