Light, Shadows and Reflections: science class six
Light helps us to see an object
It is the light that helps us to see an object. Without light, we cannot see anything.
Rays of light get reflected after falling on an object and reach our eyes, this enables us to see the object. If there is no light, we will not be able to see the object because no light will reach our eyes.
This is the cause that in a dark room we cannot see any object.
Why do we see the objects during the day?
During the daytime, the Sun is in the sky above us. Light coming from the sun falls on objects. After falling on the objects some of the light gets reflected and reaches our eyes, this enables us to see the objects in the daytime.
We can observe with the setting of the Sun it becomes difficult to see the objects outside. After setting the Sun gradually light gets dim and finally, there is no light available around us. Because of the absence of light, no light falls on an object and we are unable to see the object.
In modern times we have many things that can produce light, such as electric bulbs, electric tube lights, and electric torches, etc.
By using an electric bulb, an electric torch, etc. we can be able to see objects even at the night. These produce light. And when the light from these types of sources falls on an object some of the light returns to our eyes after bouncing back from the objects on which it falls and we become able to see those objects.
You will have experienced the case of a sudden power cut in the night and you will find not be able to see any object until the restoration of electricity or an alternate arrangement.
Activity to see how light helps us to see an object
By doing this activity you will become aware that how light helps us to see an object.
It will be better to perform this activity at the night.
(Do not perform this activity alone. Perform this activity by taking your mother or father or any other elders with you because this activity requires a dark room having doors and windows closed which may be dangerous, so without the presence of any elders do not perform it.)
* Go to a room.
* Close the doors and windows (Ensure making the room completely dark by closing the doors and windows that can prevent light from coming from outside.)
* Put off all the lights to make the room completely dark.
* Now, try to see the objects.
Would you be able to see the objects kept in the room?
No, you would not.
You will not be able to see the objects in the room because there is no light present there and consequently no ray of light is reaching your eyes after reflecting from any object.
* Now take a torch and put it on and throw the torchlight on an object.
* Now you will be able to see the object on which you are pointing the light.
This happens because light reaches your eyes after reflecting from the object.
Do you able to see other objects too in the room?
You would be able to see other objects also kept beside the object on which you are pointing the light of the torch.
This happens because some of the light rays coming from the torch reach your eyes after reflecting from the objects kept beside the main object on which you are throwing the light.
But you will notice that you can see the object more clearly and brightly on which you are throwing the light and other objects which are not directly in the way of the beam of the light of the torch are not very clearly visible, and appear less bright.
This activity shows that without light we cannot see an object. And we see the object when light rays reach our eyes are reflecting from an object.
Did you know where does the Sun go after setting?
Our earth is spherical in shape. Our earth moves continuously on its axis like a top. This type of movement of a spherical object like our earth is known as Rotation. Our earth takes about 24 hours in taking one round on its axis. In the night, the Sun goes to the other side because of the movement of the sphere of the earth. This is the cause that we do not see the Sun at the night.
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