Test: How Things Work - Class 4 MCQ

Spinners with holes off-center don’t spin well because they are not balanced. This makes them wobble and stop quickly.

An empty steel bowl floats because it holds air, which makes it light enough to stay on water.

An iron nail sinks in water because it is heavy and dense, so it goes below the surface.

Changing an object’s shape can make a heavy object float. For example, flat aluminium foil floats because it holds air, but a foil ball sinks.

A spinner with a toothpick in the center spins well because it is balanced and doesn’t wobble.

When a spinner spins fast, the colors blur and mix together, making them look like one color.

The weight and shape of an object decide if it floats or sinks. For example, a heavy steel bowl can float if its-shape holds air.

A coin shakes when it spins because it is not balanced. This makes it wobble and stop.

Balance helps an object spin well. Balanced objects like coins spin smoothly, but unbalanced ones wobble.

Objects float if their shape holds air, like a steel bowl. If they don’t hold air, like a foil ball, they sink.