The Sun and Water

Science - Unit H Day 4 Water Cycle Model

TODAY’S TARGET: Create a model to explain the parts of the water cycle. Water can be a gas, a liquid, or a solid and can go back and forth from one state to another.

Multiple Choice

The sun is the source of heat energy that drives the water cycle on Earth. Four students created labeled diagrams of the water cycle. Which of the following lists of labels includes all of the main parts of the water cycle?     

• evaporation, condensation, precipitation, runoff, collection

•  the Sun, evaporation, precipitation, runoff, collection

• the Sun, evaporation, condensation, reservoirs

• the Sun,, evaporation, condensation, precipitation

​Modeling the Water Cycle

​The Sun is the engine that drives the water cycle. Without the heat of the Sun, water would not change state from a solid to a liquid to a gas. Without the Sun, all water on Earth would be solid: the Earth would be an ice planet. At one point in Earth’s past, hundreds of millions of years ago, Earth was in fact an ice planet. Life survived in the liquid oceans under the frozen surface.

Multiple Choice

Without the sun, the Earth would be a __________ planet.

• round

• water

• ice

• blue

Any model that is meant to explain the parts of the water cycle must include a heat source to represent the Sun. If the model is a drawing, then the Sun must be included as part of the drawing. A simple model of the water cycle would be a cup of water with plastic wrap on the top, sitting under a light bulb. The light bulb is the heat source that represents the Sun. When the light is turned on, it will heat the water inside the cup. As water vapor rises to the inside surface of the plastic wrap, it will condense and form droplets of water.​

Multiple Choice

The lamp shining on the bottle in the diagram represents _____________.

• The atmosphere

• The Sun

• The Earth

• The Oceans

​Another similar model might be a plastic tub. The tub can be placed on an angle, so that water is on the low side. The high side can be filled with sand or clay to represent the land. A clear lid is placed over the tub, and again, a light bulb is used to represent the Sun. When the light is turned on, water will evaporate and condense to form droplets on the inside of the lid. It is possible that some of those droplets would get large enough to fall and model rain.

Multiple Choice

Why is there a bucket of ice cubes on top of the aquarium?

• to represent air cooling as it gets higher

• to represent air warming up and melting ice cubes

• to represent water vapor in the air

• to represent the sun warming the air

• t

​One more model that could be created to model the water cycle would be to use a resealable baggy. Soak a paper towel with water, and place it inside the baggy. Fill the baggy with air, and then seal it. Use tape to hang the baggy in a sunny window. As the heat of the Sun heats the water in the soaked paper towel, it will evaporate. The inside of the baggy will fill with invisible water vapor. When the water vapor in the baggy touches the cooler sides of the baggy itself, it will condense into droplets of water. Some of these droplets will drip down the sides of the baggy. The paper towel will absorb the water that drips down, and the cycle will continue.

​Remember our investigation?

Multiple Choice

When the water vapor in the baggy touches the cooler sides of the baggy itself, it will __________ into droplets of water

• freeze

• condense

• evaporate

Multiple Choice

A student has created a model of the water cycle. She has used a clear plastic tub. One side of the tub has a mound of clay represent an island. She has filled the tub with one inch of water, and placed a clear lid on top of it. She places the model on a counter in her classroom, along the wall opposite the windows. After several days observing the model, she notices that droplets of water do NOT appear on the inside of the lid. What part of the water cycle has the student not included in her model?

• water

• land

• sun

• atmosphere

Multiple Choice

Which part of the water cycle causes the water droplets to from on the glass cover?

• condensation

• evaporation

• precipitation

• runoff

Multiple Choice

What part of Ashley's model represents precipitation in the atmosphere?

• droplets forming on the pan

• water vapor rising from the beaker

• water drops falling from the pan

• water heating inside the beaker

Multiple Choice

In the model, the water droplets will fall directly into the water at the bottom of the tank.

How can this water cycle model be changed or modified to demonstrate runoff?

• Remove the glass cover so the water vapor can escape the tank, just like the water vapor escapes the Earth's atmosphere

• put a hose into the tank so that water flows out just like a river flows across the surface of the Earth

• Runoff can NOT be demonstrated in a model of the water cycle

• add something, like a bucket, to the bottom of the tank just below the ice cubes so the water drops will fall on top