Adolescence: A Stage of Growth and Change — Science STD 7 — Question

Explain the process of breathing in insects and fishes.

Last Sunday, Pooja on her week off entered in her kitchen to cook rice for her family in lunch time. The moment she put fry pan on the gas stove and lighted it through the matchstick, all of sudden her 5 years small daughter entered into the kitchen and tends to touch the hot fry pan. At the same time, Pooja saw her and pushed her away from the hot fry pan. In this way, she saved her child.
(i) Explain why are the fry pan provided with the plastic handles?
(ii) Mention the values represented by Pooja here towards her 5 years small daughter.

Predict what would happen if all metals turned non-sonorous.

Define the term breathing rate.

Design an eco-friendly experiment to show gas exchange in plants without harming them.

Why is the Moon able to block the entire Sun even though it is much smaller?

The image formed by a lens is always virtual, erect and smaller in size for an object kept at different positions in front of it. Identify nature of lens.

While going for a school picnic, Paheli decided to note the reading on the odometer of the bus after every 30 min till the end of the journey. Later on she recorded her readings in table.
Odometer reading at different times of the journey

Time (AM)	Odometer readings	Distance from the starting point
8:00	36540 km	0 km
8:30	36560 km	20 km
9:00	36580 km	40 km
9:30	36600 km	60 km
10:00	36620 km	80 km

(i) Can you tell how far was the picnic spot from the school?
(ii) Can you calculate the speed of the bus?
(iii) Looking at the table, Boojho asked Paheli whether she can tell how far they would have travelled till 9:45 AM.

Why tropical rain forest has large population of animals?

Does the electric current have other effect except heating? Name it.