Light and shadows grade 5 cbse_Deepa Unnikrishnan

CLASS 5 _SCIENCE_LIGHT AND SHADOWS By Deepa Unnikrishnan, Indian School Al Seeb , Sultanate of Oman

1. CLASS V DEEPA UNNIKRISHNAN

2. Light Light is a form of energy which is responsible for the sense of sight . It enables to see things around us. Light enables us to see every object around us like trees, vehicles, houses, people, etc. At night due to the absence of sunlight, it becomes dark, which reduces our visibility. DEEPA UNNIKRISHNAN

3. Objects that emit light are called Luminous Objects like sun, bulb, tube light. Any non-light emitting object is visible when light from a luminous source falls on that object and then reaches our eye . These objects are called Non-Luminous Objects like trees, animals, shoe, moon (it seems glowing because of sun’s light falling on it) etc. Luminous & Non-Luminous Objects DEEPA UNNIKRISHNAN

4. T ransparent, Opaque and Translucent Objects Objects are classified based on amount of light that can pass through them . DEEPA UNNIKRISHNAN

5. Opaque Translucent Transparent These objects do not allow light to pass through them. These objects allow light to pass through them partially. These objects allow light to pass through them completely. We can’t see through these objects. We can see through these objects a little but not clearly. We can see through these objects clearly. Examples wall, door, trees etc. Examples polythene, butter paper, thin plastic sheet etc. Examples air, water, clear glass, etc. MATERIALS AND LIGHT DEEPA UNNIKRISHNAN

6. T ransparent, Opaque and Translucent Objects DEEPA UNNIKRISHNAN

7. Shadows A shadow is a space where light from a light source is blocked by an opaque object. A shadow is formed when a part of light is blocked by the object. If all the light is blocked by an object, then there will not be any shadow. Shape of the shadow is always similar to that of the object but the size varies. DEEPA UNNIKRISHNAN

8. SHADOWS When it translucent or an opaque object is placed before a source of light ,a dark spot forms on the opposite side of the light . The dark spot formed by a translucent or an opaque object when it blocks the light is called a shadow . DEEPA UNNIKRISHNAN

9. SHADOWS AND TYPE OF OBJECTS Transparent objects do not form shadows as they do not block light . Translucent object forms light shadow as they partially blocks the light . Opaque object forms dark shadow as they completely blocks the light . DEEPA UNNIKRISHNAN

10. Things needed to form a shadow A source of light A translucent or an opaque object A surface (screen) on which the shadow can be formed DEEPA UNNIKRISHNAN

11. Features of a shadow A shadow is formed on the opposite side of the light source . A shadow is black even when the object is of any other color . A shadow shows only the shape or outline of the object , not the details . The size of the shadow depends on the distance between the object and a source of light . it also depends on the distance between the object and the surface where it formed . DEEPA UNNIKRISHNAN

12. when is a shadow shortest ? why it appears shortest ? Shadows formed by the sun are shortest at noon because the size of the shadow depends on the distance between the object, the surface where it formed and the source of light . At  noon , the sun is directly overhead ( sun is near to earth compared to mornings and evenings ). so the rays fall vertically on the object. So Shortest shadow is at noon. DEEPA UNNIKRISHNAN

13. The  shadow  is longest in the morning and evening because in mornings and evenings, the sun rays fall at an inclined position. i.e. sun is far away from earth in the morning and  evening . DEEPA UNNIKRISHNAN

14. Shadows cannot occur in dark rooms. Why? Shadows cannot occur in dark rooms due to absence of light and full lit rooms with no objects due to absence of opaque object. A shadow is always obtained on a screen like walls, ground etc. A shadow is always black or grey irrespective of the colour of the object. DEEPA UNNIKRISHNAN

15. https://youtu.be/WNKIdIE4Aec?list=PLHOGBLPrsnMox4LaHbMIaUA4fvbl0bu1z&t=33 https://youtu.be/bh-JCO5UmrA?list=PLHOGBLPrsnMox4LaHbMIaUA4fvbl0bu1z https://youtu.be/FtIz9BktzG4?list=PLHOGBLPrsnMox4LaHbMIaUA4fvbl0bu1z https://youtu.be/P6Uihn8V3h4?list=PLHOGBLPrsnMox4LaHbMIaUA4fvbl0bu1z https://youtu.be/V6pjHnA39CQ?list=PLHOGBLPrsnMox4LaHbMIaUA4fvbl0bu1z https://youtu.be/DavnmxgVwaw?list=PLHOGBLPrsnMox4LaHbMIaUA4fvbl0bu1z https://youtu.be/OAgRTdIgZGs?list=PLHOGBLPrsnMox4LaHbMIaUA4fvbl0bu1z https://youtu.be/yd5WRAgl1cQ VIDEOS DEEPA UNNIKRISHNAN