Light enables us to see objects by traveling in straight lines. There are two types of objects: luminous objects like the sun and stars that produce their own light, and non-luminous objects like trees and cars that require a light source to be visible. Objects can be opaque and block all light, transparent and let all light pass through, or translucent and only let some light through. Shadows form when an object blocks light, and reflections occur when light bounces off a smooth surface like water or a mirror.

1. LIGHT, SHADAOWS AND REFLECTIONS

2. How do we see things around us ?
 We see so many objects around us, colorful and
different. On the way to school we see things like
buses, cars, cycles, trees, animals and sometimes
flowers. How do you think, we see all these objects?
 can you imagine to see things in dark room?

3. What is light?
 Light is the form of energy that enables us to see
objects around us.
 Nothing is visible to us in dark room and unless an
object is lighted, its not visible to us.

4. Sources of light
 LUMINIOUS OBJECT: object that gives off light of their
own. For ex sun, stars etc.

5.  NON LUMINIOUS OBJECT: objects that do not give out
light of their own. For example table , chair, book,
pencil etc.

6. OPAQUE OBJECTS
 Opaque objects do not let any light to pass through
them.
 Examples: wood

7. TRANSPARENT OBJECTS
 Transparent object allow us to see clearly through
them.
 Examples: glass window

8. Translucent objects
 Translucent object only let some light through them.
We cannot see clearly through a translucent objects.
 Examples butter paper, plastic sheet

9. PROPOGATION OF LIGHT
 Light always travel in straight lines
 This property of light to travel in straight line called
rectilinear propagation of light

10. ACTVITY
 AIM: To verify that light travel in a straight line.
 Material needed: a rubber tube about 40-50 cm long, a colorful.
 Method:
 1 Place a candle in front of you , and now with the help of the rubber
tube, see the flame of lighted candle.
 2 What do you see?
 3 Now bend the tube and try to see the flame again. Would you able
to see the flame?
 OBSERVATION: This indicate that light travel in straight line.

11. SHADOW
 Any object can make a shadow if it blocks the light.

12. Properties of shadow
 A shadow is always dark and is formed only where there is bright
light.
 .The shadow is always formed in direction opposite to that of the
source of light.
 The shape and size of the shadow depends upon the source of light
and on object

13. Images
 When a beam of light falls on the polished surface it is
reflected back and we are able to see that image of
the object through our eyes.

14. Reflection
• Reflection is light bouncing off a very smooth surface.
• You look into the mirror and see your own face inside
the mirror. What you see is a reflection of your face in
the mirror.

15.  Mirror are smooth reflecting surfaces.
 Water also act as reflecting. It’s a regular or smooth
reflecting surface.

16. Now your turn
 Classify the given objects as luminous and non
luminous objects
 Moon, bulb, sun, candle, wood, stars, shoe, pencil,
table , book.
 Luminous Non luminous
 Bulb wood
 sun shoe
 candle pencil
 stars table ,book

17. Classify the objects in the table as the
transparent, translucent, and opaque.
 Objects classification
 Spectacle lens transparent
 Plastic sheet translucent
 Metal spoon opaque
 Clear water transparent
 Wooden door opaque

18. REFERENCE
 N.C.E.R.T CLASS 6
 JIWAN GLOBAL SCIENCE CLASS 6
 GOOGLE IMAGES
 WIKIPEDIA
 GOOGLE

19. THANKYOU