Have you ever wondered how would the world be without light?
Dark and scary, Right?
Thanks to light, we see the world around us in glorious colors.
But what is light and how does it help us see things?
In the class, we shed some light on light and learn light in detail.
Class Summary:
2:50 – What does it mean when we say we can see something?
It means that the light hits the surface of that object and then that light travels to our eyes so we can see.
Reflection is how we use light to see around us.
Like the moon which reflects sunlight so we can see it shining in the sky.
3:10 – So What is that we need to see? Yup, you got it right. Light, it is!
3:45 – Where does this light come from?
our main natural light source is the sun. Other sources include fire, stars, and human-made light sources like light-bulbs and torches.
6:45 – How fast does this light travel?
The speed of light equals 300,000 km/second. Nothing else travels faster than light, not even sound! And that’s exactly why we see the lightning first and then hear the thunder.
Quiz time – How much time do we need to see a bulb switched on 3 lakh km away? And how much time if the bulb is 12 lakhs kn away?
8: 51 – How long does the light of the sun take to reach earth?
It takes just over 8 minutes for light to travel from the Sun to Earth, a distance of 148 million km.
10: 01 – Looking at other stars is like looking back in time – when we look at a star, we are actually seeing what it looked like years ago. When we look at a star, we are looking at the light that came from the star. Because stars are so far away, it takes years for their light to reach us. As long as 40 thousand years sometimes.
13:01 – How is this distance traveled by a light measured? In light-years.
13 – 50 – Light Year = Distance that light travels in one year = 365 x 24 x 60 x 60 x 300000 km
14: 55 – You can use Havi Code to calculate the above equation and write your answers in the comment below.