The water cycle

Grade 2 Science 

Content

• Water sources including local watersheds
• Water conservation

Curricular competencies

Questioning and predicting

• Demonstrate curiosity and a sense of wonder about the world
• Observe objects and events in familiar contexts
• Ask questions about familiar objects and events
• Make simple predictions about familiar objects and events

Planning and conducting

• Make and record observations 

Processing and analyzing data and information

• Sort and classify data and information using drawings and pictographs
• Compare observations with predictions through discussion

Evaluating 

• Compare observations with those of others

Applying and innovating

• Transfer and apply learning to new situations

Communicating

• Communicate observations and ideas using oral or written language, drawing or role-play

The activities in this unit provide an opportunity to assess individual students and small groups on their ability to:

• Identify the stages of the water cycle 
• Make predictions about where rain comes from and what will happen during the experiment
• Make and record observations during the experiment
• Communicate observations about the experiment and the water cycle
• Generate questions about the water cycle
• Work together in small groups

Water cycle

Earth has a limited supply of water that is cycled over and over again. The water cycle is an important process on earth because living things, including animals and humans, need water to grow and survive. Water is used for drinking, growing food, providing habitat, generating electricity and more. The sun has been driving the water cycle on Earth for billions of years. The four main stages of the water cycle are evaporation, condensation, precipitation and runoff.

• Sun: the water cycle is driven by the energy from the sun warming the earth.
• Evaporation: the warmth of the sun causes water from lakes, rivers and oceans to evaporate and turn from a liquid to a gas. The water vapour (gas) rises up into the air. 
• Condensation: the water vapour cools as it rises and turns back into water droplets, forming a cloud.
• Precipitation: water droplets in a cloud eventually become too big and heavy and fall from the clouds in the sky. It can fall as rain, snow, hail, etc.
• Runoff: after the precipitation falls, it flows down towards the ocean and collects in rivers, lakes and streams. Some of it collects underground as well. 
• And then the cycle begins again.