6. What are the three things needed to form a shadow?
A.1 .A source of light (eg: sun)
2. A surface (eg: screen)
3. An object
7. List three important features of shadows.
A. 1. A shadow will form if the object is in between the source of light and the screen.
2. It forms on the opposite side of the source of light.
3. It is generally grey or dark in colour.
8. Describe how the length of a shadow changes during the day.
A. During day time the shadow formed by Sun varies according to the time. During morning and late afternoon Sun forms the longest shadow whereas during midday or noon shadow formed is shortest. During the time of longest shadow formation Sun is low in the sky and during the shortest shadow formation Sun is directly overhead.
Define the terms:
1. Transparent material: Materials through which most of the light passes are called transparent materials.eg: clear glass, water.
2. Shadow: The dark patch formed on a surface when the path of light is blocked by an object.
A. 1. b 2. c 3. a 4. a 5. d
B. 1. True
2. False: We can see objects around us because light gets reflected off their surfaces.
4. False: Clear glass is transparent but frosted glass is translucent.
5. False: A shadow is formed on the opposite side as the source of light.