Conservation of Plants and Animals — Science STD 8 — Question

What happens when:
Dilute sulphuric acid is poured on a copper plate?
Write word equations of the reactions involved.

Why is the more necessary for adolescents to take bath regularly (at least once every day)?

Give the name of scientist who actually established the relation between sparks produced by amber and thunderstorms. Explain in brief.

After how many days, the moon achieves its full moon phase?

An archer stretches her bow while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information, fill up the gaps in the following statements using the following terms: muscular, contact, non-contact, gravity, friction, shape, attraction
(a) To stretch the bow, the archer applies a force that causes a change in its ____________ .
(b) The force applied by the archer to stretch the bow is an example of ____________ force.
(c) The type of responsible for a change in the state of motion of the arrow is an example of a ____________ force.
(d) While the arrow moves towards its target, the forces acting on it are due to ____________ and that due to ____________ of air.

Why are the voices of men, women and children different?

Explain how does a sound making object differ from one that is silent.

Last Monday, Ankush woke up late in the morning. So, he saw the time and suddenly realised that he had got late for an interview, which he was supposed to give after reaching the venue by the right time. Immediately, he turned ON the geyser but it did not work. He got more tensed, then he used an electric Iron rod through which he could get some boiled water for his bath. Actually, there was an earthing problem in the switch board which he was unaware of. He was barefoot and was just about to switch ON the electric iron rod but at the same he was stopped from doing so by one of his room partner living with him. It could be dangerous for Ankush.
(i) Explain in brief that what could be happened with Ankush, if he switched ON the electric iron rod (without wearing any slippers in his foot).
(ii) Mention the values showed by Ankush's friend.

Define a lightning conductor.

Explain why plastic containers are favoured for storing food.