Test: Weather, Water and Air- 1 - Class 4 MCQ

If the clouds are very cold, water vapour   condenses   to   form snowflakes of different shapes.

• When the sun heats the water on the earth's surface, it starts to evaporate and rise up into the air. This process is like when you put a wet cloth in the sun and it dries up.
• The water turns into tiny water droplets in the air, forming clouds. This is how the water cycle begins, where water moves from the earth into the air and back again as rain or snow.

• In the activity with the candle and matchstick, we saw that when we lit the candle, the air around it got hot.
• When you put your hand above the flame, you could feel the heat.
• This is because the hot air from the flame goes up.
• So, it is true that warm air rises up.
• This is because hot air is lighter than cold air, so it goes up towards the ceiling.
• Remember, hot air balloons fly because they are filled with hot air that rises in the sky!

Due to the heat of the sun, warm air rises and cool air rushes in to take its place. This causes the wind to blow.

When the land cools down faster than the sea at night, the cooler air above the land moves towards the warmer sea, creating a breeze. This movement of air from land to sea is called a land breeze.

95% of the air constitutes of oxygen and nitrogen.

• The sun's heat causes different weather changes on Earth.
• The sun shines on different parts of the Earth at different times, making some places hotter than others.
• This heat makes the air move around, creating wind and causing changes in the weather.
• So, the sun plays a big role in making our weather change every day.

Frozen dew is called frost.

Water changes from one state to another due to heating and cooling. When water is heated, it can change from a liquid to a gas (vapour) through a process called evaporation.

In humid weather, there is a lot of water vapor in the air. This makes it hard for your sweat to evaporate quickly, which can make you feel hot and uncomfortable. So, the statement is True.

When the sun shines brightly, it heats up the ground. This makes the ground warm and helps in creating weather changes like wind and rain.

On cold winter mornings water vapour condenses on dust particles to form fog.

The water cycle helps in recycling of water from the earth to the sky.

Wet clothes dry fast on a sunny and windy day.

• In easy words, this means that most of the earth is covered by water.
• It is like a big blanket of water around the land. This water can be found in rivers, seas, ponds, lakes, and even in the form of ice and glaciers.
• So, the statement is True because water does cover a large part of the earth's surface.