The water cycle | Year 4 Science PDF Download

Understanding the Water Cycle

• Water on Earth is in constant motion, undergoing a process of recycling known as the water cycle. 
• This cycle involves the journey of water as it moves from the land to the sky and back again.

Stages of the Water Cycle

The water cycle describes the continuous movement of water as it circulates between the Earth's surface and the atmosphere.
Let's explore the different stages of the water cycle:

Water Evaporates into the Air

• The heat from the Sun causes water in oceans, lakes, rivers, and on land to warm up.
• This warm water transforms into a gas known as water vapor through a process called evaporation.
• Unlike boiling, where water reaches its boiling point of 100 degrees Celsius, evaporation occurs even when the water is below this temperature.
• Evaporation is a slower process compared to boiling, as it involves the gradual conversion of liquid water into vapor.

Water vapor condenses to form clouds

• As water vapor rises, it cools and condenses.
• This process creates tiny droplets of liquid water, forming clouds.
• The wind moves the clouds.

Water falls as precipitation

• As water droplets in the clouds grow larger, they become heavier.
• Eventually, they fall, typically as rain.
• If the air is very cold, the water freezes and falls as hail or snow.
• Rain, snow, and hail are all forms of precipitation.

The water returns to the sea

• Water that falls on land flows through streams and rivers back to the sea.
• The cycle then begins again.