Changes Around Us: Physical and Chemical — Science STD 7 — Question

Explain how water heated by convection?

How you can find out wind direction at a given place.

An electrician is carrying out some repairs in your house. He wants to replace a fuse by a piece of wire. Would you agree? Give reasons for your response.

Draw a neat and clean diagram of Amoeba showing the correct location of the following components: nucleus, vacuole, pseudopodia.

Differentiate between uniform and non-uniform motion.

Note the distance between the two stations and the time taken by the different trains to cover such distance. Calculate speeds of the trains and find the fastest and slowest train.

Research famous scientists (e.g., Marie Curie, Antoine Lavoisier) and their contributions to the understanding of chemical reactions and changes. Create a timeline or a presentation about the history of chemical discoveries.

Harish went to visit his grandfather in village where he saw that his grandfather’s field of wheat are infected with fungus but no one is aware of this. Harish rushed to his grandfather’s side and told him that the field have been infected with fungi. He should use an antifungal agent in his fields to stop this infection.

1. What is fungus?
2. Can fungus only cause diseases or can it be helpful also?
3. What values are shown by Harish?

What happens when magnesium oxide is dissolved in water? Write a word equation for this process. Name the type of change which takes place.

Sketch the reproductive parts of a flower.