The Eye and the Camera

The eye and the camera

Aims

This is an alternative lesson for Topic 3.4 The eye and the camera. In this lesson, students start by looking at a 6-mark question. The aim of the lesson is to move students towards answering the question, using knowledge they have from previous lessons, and covering new learning objectives related to the Student Book.

This lesson is designed to be a direct replacement for the Teacher Handbook lesson for this topic. It covers the following learning objectives:

Describe features of the eye and the pinhole camera.
Compare the similarities and differences between the eye and the camera.

Big Question

Compare the eye and the camera. (6 marks, QWC)

Question requirements

For students to be able to answer the question, they need to:

Statement / Answer
Describe features of the eye and features of a camera. / The eye has a lens, pupil, and retina. It also has a cornea, and iris.
The camera has a lens, aperture, and film or CCD. It also has a shutter.
Describe differences in features of the eye and a camera. / The eye and camera each have a lens, aperture (pupil), and light-sensitive material. The camera has a shutter and mechanism to move the lens, the eye has a mechanism to change the shape of the lens. The lens focuses light; in the camera the lens moves and in the eye it changes shape; both have light-sensitive material.
Describe features of images produced by the eye and by a camera / In a camera the image is real and can be saved. The image in the eye is virtual and cannot be saved. In the camera the image is inverted on the screen and in the eye the image is inverted on the retina.

Question marking guidance

Compare the eye and the camera. (6 marks, QWC)

1–2 marks

There needs to be a basic description they eye and of a camera. Students should give at least two of the scientific points given below, with at least one point made about each the eye and the camera.

3–4 marks

There needs to be a clear description of the similarities and differences between the eye and the camera. Students should give at least four of the scientific points given below. Spelling and grammar is mostly correct.

5–6 marks

There needs to be a detailed description of the similarities and differences between the eye and the camera, including the similarities and differences between the types of images made. The explanation is clear, and in a logical sequence allowing for easy comparison. Spelling and grammar is all, or nearly all, correct. Students should give at least six of the scientific points given below.

Scientific points

They both have a lens to focus the image.
There is an aperture in the camera and a pupil in the eye.
Both have a light-sensitive screen where the image is formed.
The eye and digital camera produce electric signals (a film camera does not).
The lens is focussed by changing shape in the eye and by changing position in the camera.
The retina has light-sensitive cells where there is a chemical reaction; the camera has a
CCD device.
The image made on the retina is virtual and cannot be saved.
The image made in a camera is real and can be saved.
The images made in both the eye and a camera are inverted.

Starter / Support/Extend / Resources
Introducing the question (5 minutes)
Give students the Question-led lesson student sheet and write the Big Question on the board. Explain to students that by the end of this lesson, they will be able to answer the question. Students should record key words and answers to the question requirements table as they move through the lesson.
What do lenses do? (5 minutes)
Pupils look through convex lenses and describe the images seen when objects are varying distances away. Nearby objects are magnified; distant objects are smaller. If they are shown on a screen, images are inverted.
Parts of the eye (5 minutes)
Pupils name as many parts of their eye as possible. Identify the cornea and use mirrors to see the size of the pupil change with changing light levels; explain how muscles in the eye change the shape of the lens as pupils focus on near and far objects. / Extension: Link shape of lens (thickness) to focal length.
Support: Use the image in the textbook.
Extension: Students match parts of the eye to their function. / P1 3.4 Activity: Question-led lesson
Main / Support/Extend / Resources
The eye and the camera (25 minutes)
Explain that the eye and camera perform similar jobs. Explain what each part of the eye and the camera do, and identify these on a diagram. Demonstrate a model eye and a model pinhole camera to students. It is important to explain that the cornea and the fluid inside the eyeball help focus light, as well as the lens. Compare changing the distance between the lens and the film in a camera with changing the shape of the lens in the eye to focus on different objects. Students use the diagrams on the Activity sheet to name the parts of the camera and eye that light travels through in the correct sequence. Students use the Activity sheet to summarise the information by answering the questions.
Completing the student sheet (10 minutes)
Students answer the Big Question on the student sheet. / Support: Add labels to models before students handle them. Use cards with named parts of the eye and camera for students to sort or sequence.
Extension: Students explain using ray diagrams why the images produced are upside down. / P1 3.4 Activity: Modelling the eye and the camera
Plenary / Support/Extend / Resources
Identifying ways to improve (5–10 minutes)
Working in pairs, students should list ways to improve their work, first suggesting their own improvements and then looking at their partner’s work to suggest improvements or to look for good ideas on how to improve their own answer. / Support: Students may struggle to identify how they can improve the quality of their writing (structure, spelling). Sharing the best answer from the class will help students appreciate the difference in QWC.
Homework
Students should revise their answer using their improvements identified in the plenary.

This resource sheet may have been changed from the original.