CBSE Class 4 EVS How Things Work MCQs Set 01

Answer: (C) It begins to shake

Explanation:
1. When a top spins fast, it stays upright and steady.
2. As it slows down, it loses its spinning balance.
3. This loss of balance makes the top wobble and shake before it falls over.

Answer: (B) Light material

Explanation:
1. Paper is very light in weight.
2. Light things do not push hard against the water.
3. This light weight helps the paper ship stay on top of the water instead of sinking.

Answer: (C) Wood

Explanation:
1. Long ago, people did not have plastic to make toys.
2. They carved tops out of wood because wood was easy to find and cut.
3. Wood is also strong and can spin very well.

Answer: (B) Coin

Explanation:
1. A coin is round and flat.
2. It can balance easily on its edge when we spin it.
3. Other things like erasers and stones are bumpy and cannot spin.

Answer: (B) Position of the hole

Explanation:
1. To spin nicely, a spinner must be balanced on all sides.
2. The hole must be exactly in the center to keep it balanced.
3. If the hole is off-center, one side becomes heavier, and it will shake and stop spinning.

Answer: (A) The edges blur

Explanation:
1. When a square spinner rotates very fast, our eyes cannot see the corners clearly.
2. The corners and edges move so fast that they mix together and look blurry.
3. This blur makes the square shape look like a round circle to us.

Answer: (C) Leaf

Explanation:
1. A leaf is flat and very light.
2. It spreads its tiny weight over a wide area on the water.
3. This helps the leaf stay on top of the water and float.

Answer: (B) At the center

Explanation:
1. The center is the middle point of the spinner.
2. Putting the stick in the middle keeps the weight equal on all sides.
3. This helps the spinner stay balanced and spin for a long time.

Answer: (A) Its shape

Explanation:
1. A top has a special shape that is wide at the top and narrow at the bottom.
2. This balanced, round shape helps it spin smoothly around its center.
3. It will wobble and fall if its shape is not perfect and balanced.

Answer: (B) Lattu

Explanation:
1. A lattu is a wooden toy that spins on a metal nail at the bottom.
2. People in India have played with it for a very long time.
3. It is spun using a long thread wrapped around it.

Answer: (C) Thermocol

Explanation:
1. Thermocol contains a lot of trapped air inside it.
2. Because of this air, thermocol is extremely light for its size.
3. Light things with lots of air float easily on any liquid.

Answer: (C) The shape of the object

Explanation:
1. Shape helps decide how much water an object can push aside.
2. A flat, wide shape pushes more water and floats easily.
3. A small, tight shape cannot push enough water, so it sinks.

Answer: (B) Fan

Explanation:
1. A top spins round and round around a center point.
2. A fan also rotates around a middle point when it is turned on.
3. Therefore, both a top and a fan have the same spinning motion.

Answer: (C) It sinks

Explanation:
1. Aluminum foil normally has a lot of trapped air when it is flat or loose.
2. When we press it into a small, tight ball, we squeeze all the air out.
3. Without the trapped air, the ball becomes very dense and sinks in water.

Answer: (A) Shape

Explanation:
1. The shape of an object changes how it interacts with water.
2. For example, a wide boat shape floats, but a solid ball of the same material might sink.
3. This is why shape is a key factor that makes things float.

Answer: (B) It slows down, shakes, and stops because it loses balance

Explanation:
1. When a penny spins, rubbing with the ground makes it lose its speed.
2. As it becomes slow, it cannot stand straight anymore.
3. It starts to shake and then falls flat on the table.

Answer: (C) Twist fibre into thread

Explanation:
1. A charkha is a simple machine with a big wheel.
2. When the wheel turns, it pulls soft fibers like cotton.
3. It twists these loose fibers together to make a long thread.

Answer: (C) Circular

Explanation:
1. When the square spinner turns very fast, the corners spin around quickly.
2. Our eyes see the fast-moving corners as a continuous line.
3. This continuous path looks like a round circle or a circular shape.

Answer: (A) To twist cotton into thread

Explanation:
1. A charkha is a traditional spinning wheel.
2. It takes soft, loose cotton fibers and spins them.
3. This spinning twists the fibers tightly to make strong thread.