List of top Science Questions

Explain how deforestation leads to reduced rainfall.
Fill in the blanks:
  1. Most liquids that conduct electricity are solutions of ___, ___ and __.0.
  2. The passage of an electric current through a solution causes ___ effects.
  3. If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the ___ terminal of the battery.
  4. The process of depositing a layer of any desired metal on another material by means of electricity is called ___.
In order to meet the ever-increasing demand in factories and for shelter, trees are being continually cut. Is it justified to cut trees for such projects? Discuss and prepare a brief report.
In an experiment \(4.5\) kg of a fuel was completely burnt. The heat produced was measured to be \(180,000\) kJ. Calculate the calorific value of the fuel.
Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?
Show the shape of the distance-time graph for the motion in the following cases:
(i) A car moving with a constant speed.
(ii) A car parked on a side road.
Fill in the blanks:
  1. Burning of wood and coal causes ___ of air.
  2. A liquid fuel, used in homes is ___.
  3. Fuel must be heated to its ___   ___ before it starts burning.
  4. Fire produced by oil cannot be controlled by ___.
An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?
Give two examples of each.
1. Kharif crop
2. Rabi crop
Show with the help of a sketch that plants are the ultimate source of food.
Four children were asked to arrange forces due to rolling, static and sliding frictions in a decreasing order. Their arrangements are given below. Choose the correct arrangement.
The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.
Prepare a list of objects around you that are electroplated.
Describe characteristics and uses of coke.
What are the major groups of microorganisms?
What are weeds? How can we control them?
The following Table shows the total power shortage in India from 1991–1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.
S. No.YearShortage (%)
119917.9
219927.8
319938.3
419947.4
519957.1
619969.2
7199711.5
Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?
Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain.
What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body?
Gravitational force acts on all objects in proportion to their masses. Why then, a heavy object does not fall faster than a light object?
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.
  1. What will be the action of gas on 
    (i) dry litmus paper? 
    (ii) moist litmus paper?
  2. Write a balanced chemical equation for the reaction taking place.
    An experiments with sulphur powder on a spatula and heated
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?

Here is a crossword puzzle: Good luck!

a crossword puzzle
Across 
3. Liquid waste products
4. Solid waste extracted in sewage treatment
6. A word related to hygiene
8. Waste matter discharged from human body
Down
1. Used water
2. A pipe carrying sewage
5. Micro-organisms which causes cholera
7. A chemical to disinfect water