• 2 months ago
Transcript
00:00Light and Shadow
00:07Light
00:08We always have a question in our mind.
00:14Why can we see so many stars at night, but only one star during the day?
00:24Stars are always in the sky, but the sun being the brightest of all, hides the other
00:32stars during the daytime.
00:36It is the only natural source of light.
00:41It helps us to see everything around us.
00:47It also gives us heat.
00:52At night, we cannot see anything because there is no sun.
00:59But we need light to see objects.
01:04We get this light from different man-made objects like bulbs, tube lights, candles,
01:14torches, diyas, etc.
01:22The Sun and Shadows
01:23The sun is also the cause of shadows.
01:31When the light of the sun is blocked by an object, the dark area beside that object is
01:40called a shadow.
01:44Let us do an activity.
01:46Go out in the sun at different times of the day and observe your own shadow.
01:57Move in different ways and see how your shadow changes.
02:04Play games with your shadow.
02:08The position of the sun decides the length of a shadow.
02:15At noon, the sun is overhead, so there is hardly any shadow.
02:23In the morning and afternoon, when the sun is in the east and the west, you block the
02:32sun's rays and your shadow is long.
02:38In the morning, your shadow is in the west.
02:43In the evening, your shadow is in the east.
02:48You cannot see a shadow when the sun is covered by clouds.
02:56Shadows can be seen only in the presence of light.
03:03Let us have some fun with shadows.
03:08Use a dark room and a torch.
03:12Put different objects in front of the torch light and watch the shadows.
03:20Now by using your hands, try to form shadows of animals on the wall.
03:29Try to touch something and see if your shadow touches it too.
03:35Now gently try to move your hand in such a way that your shadow continues to touch it.
03:45Now you know that you should not be scared of your shadow as it means that there is light
03:53somewhere near you.