NCERT MCQ Solutions for Class 5 EVS Looking Around Chapter 7 Experiments with Water

When a puri puffs up, it traps steam and air. This makes the puri less dense than the cooking oil, causing it to float on the surface.

An unpuffed puri does not have trapped air inside. This makes it denser than the surrounding oil, so it sinks to the bottom of the pan.

Steel is much denser than water. Because its density is greater, an object like a steel spoon will sink when placed in a container of water.

A ship’s hollow shape displaces a large volume of water, creating a strong upward buoyant force that supports its weight. A needle displaces very little water.

An empty bottle with a closed lid contains trapped air. This makes the bottle’s average density less than that of water, causing it to float.

The shape of the soap case allows it to displace a volume of water whose weight is equal to or greater than the combined weight of the case and soap.

When crumpled into a tight ball, the aluminum foil’s volume is greatly reduced. Its density becomes greater than water’s, so it sinks.

Adding salt to water increases its density. When the water becomes denser than the egg, the egg will float due to the increased buoyant force.

The Dead Sea has an extremely high concentration of dissolved salt. This makes its water incredibly dense, allowing a person to float on its surface with ease.

Stirring helps distribute sugar particles throughout the water. This increases contact between the sugar and water molecules, speeding up the rate of dissolving.

Chalk powder is insoluble in water. The particles will temporarily mix to form a cloudy suspension but will eventually settle at the bottom as sediment.

Oil and water are immiscible, meaning they do not mix. Oil is also less dense, so it floats on top of the water as separate droplets or a layer.

Water has a lower viscosity (resistance to flow) compared to thicker liquids like oil or sugar solution. This property allows it to slide down a surface faster.

When water is heated to its boiling point, it changes state from a liquid to a gas called water vapor. This process is known as evaporation.

Placing food in the sun helps to dry it out. The sun’s heat speeds up the evaporation of water from the food, which is a traditional method of preservation.

The Dandi March, led by Mahatma Gandhi, was a major act of nonviolent protest against the British-imposed salt tax and their monopoly on salt production in India.

Seawater is collected in shallow ponds. The sun’s heat causes the water to evaporate, leaving behind the solid salt crystals, which can then be collected.

A cloth acts as a filter. It can separate an insoluble solid like chalk powder from water because the solid particles are too large to pass through the cloth’s pores.

Spreading a wet cloth increases the surface area exposed to air, and the sun provides heat. Both factors speed up the rate of evaporation, drying it faster.

To make sweet tea, sugar dissolves completely in hot water. Additionally, soluble flavor and color compounds from the tea leaves also dissolve into the water.