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Perception lesson 1
- 1. Perception Lesson 1 How do we see?
- 2. Lesson Objectives • Toidentify key parts of the eye and to understand how they work
- 3. What use areour eyes? • Working in pairs • Pick something up, your pencil case, anything… • Close your eyes and describe what you know about this object to your partner • Now open your eyes and say what extra information you can access • Make a note in your book about the information that you could only find out using your eyes
- 4. Vision and Perception •Most objects in the world emit (give out) light • Light from the sun bounces off objects in the world and into our eyes • This causes a reaction in the back of our eyes (the retina) • This causes a signal to be sent along the optic nerve to the brain. • This is vision, what the brain does with that signal is perception
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- 7. The Retina • Theretina is a layer at the back of the eye • It is made up of two kinds of cells, rods and cones
- 8. Rods • Rods arevery sensitive to light and they also respond to movement • They will even respond when the light is very dim • They do not detect different colours
- 9. Cones • Cones arepacked together in the centre of the retina just opposite the pupil. • Cones help us to see fine details • Cones can detect colours • They do not work well in dim light
- 10. The Optic Nerve •When enough light falls on a rod or cone it sends an impulse (like an electric shock) to the optic nerve • All the nerve impulses travel along a bundle of fibres to the brain • It looks like a thick stalk at the back of the eye
- 11. Key Words • Perception • Retina • Rods • Cones • Optic nerve • Copy these words into your book. Look up the definitions on page 4 of the textbook. Write the definition next to the key word
- 12. Homework • Learn thekeywords and their meanings for a test