Unit 3 F Light and Shadows Unit 3

Unit 3 F: Light and Shadows

Unit 3 F: Light and Shadows

Unit 3 F: Vocabulary Useful Words Transparent A material that light can pass through, a good example is glass Opaque A material that light cannot pass through, a good example is wood Shadow A dark area formed when light is stopped by an opaque object Block To stop, an opaque object blocks light Direction The way something travels Unit 3 F: Light and Shadows

Unit 3 F: Shadows Why is a shadow formed? Unit 3 F: Shadows: L. O. 1, 2: N. C. 4. 3 b

Unit 3 F: Shadow Investigation Investigate the shadow formed on the screen. Can you change it’s size or anything about it? How can you do this? Write down anything you discover. Unit 3 F: Shadow Investigation: L. O. 1, 2: N. C. 4. 3 b

Unit 3 F: Shadows from the sun 1. What will the shadow look like at different times of the day? 2. How will you check this? 3. Why does the shadow change as you have described? Unit 3 F: Shadows from the sun: L. O. 3, 4, 5, 6, 7, 8, 9: N. C. 4. 4 b

Unit 3 F: The sun ‘moving’ across the sky Unit 3 F: The sun 'moving' across the sky: L. O. 10, 11: N. C. 4. 4 b

Unit 3 F: Shadows: L. O. 12: N. C. 4. 3 b

Unit 3 F: Does the Sun move on the same route everyday? Investigation: Does the Sun move on the same route everyday? This ‘investigation’ will take a number of days to complete. At 9: 00 mark on the window the position of the sun. Repeat this at 10: 30, 12: 00, 13: 30 and 15: 00. You then need to repeat this process for a total of at least 3 days. Why is it important to view the position of the sun from the same view point every time? What do the results tell you? WARNING: NEVER LOOK DIRECTLY AT THE SUN! Unit 3 F: Does the sun move on the same route every day? : L. O. 13,

Unit 3 F: Shadow Sizes Investigation: Shadow Sizes This ‘investigation’ will require you to take a number of measurements at different times of the day. Is the sun at the same height in the sky all day? When is it highest? Does the position of the sun have any effect on the size of the shadows it produces? Use a shadow stick to measure the size of the shadow the sun produces at 9: 00, 10: 30, 12: 00, 13: 30 and 15: 00 Time Length of shadow 9. 00 10. 30 12. 00 13. 30 15. 00 What do the results show? Do we need to repeat our measurements? Unit 3 F: Shadow Sizes: L. O. 15: N. C. 4. 4 b

Unit 3 F: The spinning earth The Spinning Earth Unit 3 F: The Spinning Earth: L. O. 16: N. C. 4. 4 b, 4. 4 c

Unit 3 F: Shadow Clocks How can the sun dial be used to tell the time? How does it work? What are the disadvantages of using a sun dial in our climate? Unit 3 F: Shadow Clocks: L. O. 17: N. C. 4. 4 b

Unit 3 F: Transparent and Opaque TRANSPARENT objects allow light to travel through OPAQUE objects do not allow light to travel through Unit 3 F: Transparent and opaque: L. O. 18: N. C. 4. 3 b

Unit 3 F: Shadows from different materials For each of the materials predict whether you think they will form a shadow or not. Test each material and record your observations. Material Prediction Observation Acetate sheet Coloured acetate sheet Plastic bottle Fine net Grease-proof paper Solid plastic Unit 3 F: Shadows from different materials: L. O. 19, 20, 21: N. C. 4. 3 b

Unit 3 F: Shadows from different materials Block light Formed when light is blocked Similar in shape to object Position ado a over e g Chan un en s h w day em s th m r o f Form Shadows Light and shadows Materials Appears to move across the sky Shortest shadow ue ws Op aq Length Sh Tr an Highest in sky at midday n ar en t Lets light through cen slu n Tra Su sp t Does not move but earth spins Shadow formed by sun Can tell approx time Unit 3 F: Light and Shadows Some light gets through