IGNOU science practical lessons on doordarshan

The spinning top

I was going through different infotainment channels and came across some interesting practical science lessons that were demonstrated by a professor at IGNOU on Doordarshan. Impressed by the simplicity and academic importance of these lessons I decided to create a blog post dedicated to them. This can help teachers in making their students learn some scientific facts in a quick and easy manner.

Methyl alcohol canon
Attach two bottles to make a canon. Make a hole in the lower one. Fill Methyl alcohol in the top bottle and push a rubber ball into it. Now use a lighter to warm up through the hole in lower bottle. The rubber ball will be cannoned out.
This happens because methyl alcohol when reacts with air, makes water which turns into vapors and pushes the ball out with force.

Cellophane butterfly
Cut a piece of cellophane paper in the shape of a butterfly. Put this piece on your hand and you will see the butterfly raising her wings. Same will happen if you turn it upside down.
This happens because the paper absorbs moisture from your hand in its lower surface which expands and makes it look like the butterfly is raising her wings.

Audio graph
Tie a rubber balloon on top of an empty can and paste a small mirror on it. Now speak from the other end of the can while you point a laser on the mirror which is to be reflected on a wall. You will get a graph of your voice’s turbulence displayed on the wall as the length of reflected laser light varies accordingly.

The singing bowl
Take a brass bowl and hit it in center with a rod. Now use the same rod to circle the bowl along its circumference and it will slowly start create a singing sound. This happens because of the Mechanical energy that gets produced in the bowl.

The spinning top
“Lattu” as we call it in India is a good example of teaching gravitational force to students.

I hope this helps 🙂