Write a note on thermostat.

How lightning takes place?

What are the effects of acid rain? How can we prevent them?

Write the skeleton equation for the following word equation and then balance them.
a) Carbon + Oxygen → Carbon dioxide
b) Phosphorus + Chlorine → Phosphorus pentachloride.
c) Sulphur + Oxygen → Sulphur dioxide
d) Magnesium + hydrogen → Magnesium + Hydrogen chloride chloride

How is the skeleton of a bird well-suited for flying?

Briefly describe the menstrual cycle.

Define the following terms.
a. Amplitude
b. Loudness

Thamizh Dharaga and Sangamithirai were playing with a bar magnet. They put the magnet down and it broke into four pieces. How many poles will be there?

Name the Indians worked at NASA.

Define specific latent heat of vaporization of water.

Heshna and Keerthi are friends. Keerthi’s teeth are white without caries, but Heshna has teeth with caries. Why? How is it formed?

Name the places in Tamilnadu harnessing wind energy from wind mills.

What is crop rotation?

Is it possible to find Dinosaurs today? Why?

What is the right alignment?