| Method |
Precise Learning Objective |
Linked |
Question / Activity
(Designed for maximum working out) |
Stepping Stones |
Pitstop Check
(Thinking Map) |
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The distance from the lens to the principal focus is called the focal length. |
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(Physics Only)What is the focal length? Recall / describe the key features of a ray diagram where light passes through a lens. Students should be able to identify the:
• Principal axis
• Principal focus
• Focal length. |
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The magnification produced by a lens can be calculated using the equation: magnification = image height / object height |
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(Physics only) What is the equation that links image height, magnification and object height? Recall and use the magnification equation. |
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Magnification is a ratio and so has no units. |
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(Physics only) What are the units for magnification? |
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Image height and object height should both be measured in either mm or cm. |
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(Physics only) What is the unit for image height? |
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Ray diagrams are used to show the formation of images by convex and concave lenses. |
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(Physics Only) How can images by convex and concave lenses be represented? Investigate the images produced using convex and concave lenses using the window and a whiteboard to project the image onto. Stand with back to the window and hold the lens in front of your face. |
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Students should be able to construct ray diagrams to illustrate the similarities and differences between convex and concave lenses. |
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(Physics Only) How could you illustrate the similarities and differences between convex and concave lenses? Construct ray diagrams to show how light travels through concave and convex lenses. |
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In ray diagrams a convex lens will be represented by: <--> |
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(Physics Only) How are convex lenses represented in ray diagrams? Construct ray diagrams for a camera, a projector and a magnifying glass using a convex lens. |
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[In ray diagrams] a concave lens will be represented by: >--< |
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(Physics Only) How are concave lenses represented in ray diagrams? EW: Use the correct terminology when describing the image produced by a lens, eg real, magnified and inverted for a projector. (start with a flow map) |
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The image produced by a convex lens can be either real or virtual. |
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(Physics Only) What type of images can be produced by convex lens? |
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The image produced by a concave lens is always virtual. |
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(Physics Only) What type of image can be produced by concave lens? EW: Explain the difference between real and virtual images.
State situations where real images and virtual images are produced. |
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A lens forms an image by refracting light. |
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(Physics Only) How does a lens form an image? Optics bench:
Investigate convex lenses. Using a single convex lens show how a camera can produce an image onto a photographic film. Show how when the object being looked at is further way than the focal length then the image is inverted. |
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In a convex lens, parallel rays of light are brought to a focus at the principal focus. |
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(Physics Only) How is a convex lens used to focus an image? GF: Discuss how laser eye surgery is used to correct the vision of people who wear glasses |
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