Physical and Chemical Changes — Science STD 7 — Question

Explain the physical properties of metals with examples.

Explain the importance of understanding the properties of different materials, and how does this helps in everyday life?

Explain the importance of forest.

People say that nothing goes waste in a forest. Can you explain, how?

A group of people were smoking cigarettes in a restaurant. The atmosphere was full of smoke. An old man sitting next to the group asked them to stop smoking while sitting in the premise or move out. They agreed to do so and promised not to repeat then mistake.Answer the following Questions.

1. Write any three hazards of smoking.
2. Can smoking also affect the person who does not smoke?
3. Do you support the group’s decision to not smoke in public or indiviually. What values do we understand from here.

Explain why
(a) an antacid tablet is taken when you suffer from acidity?
(b) calamine solution is applied on the skin, when an ant bites?
(c) factory waste is neutralised before disposing it into the water bodies?

A girl was suffering from cold and was sneezing continuously. She joined her family at dinner and suddenly started sneezing without covering her nose, thus spreading particles all over the place.
On realising her mistake, said sorry and next time covered her nose.
(i) During sneezing, what are the precautionary steps to be followed?
(ii) Is sneezing a respiratory process?

The tropical rainforest has a large population of animals. Explain why it is so.

Paheli went to the market to buy sarees for her mother. She took out a thread from the edge of the two sarees shown by the shopkeeper and burnt them. One thread burnt with a smell of burning hair and the other burnt with the smell of burning paper. Which thread is from a pure cotton saree and which one from a pure silk saree? Give reason for your answer.