Water cycle investigations

Ben Schmitz and Lara Morrow 

Focus questions

• What is a water cycle?
• What are the stages of the water cycle?

Background information

• Water enters the water cycle when it evaporates.
• Evaporation occurs when increases in energy (from the sun) is great enough to turn water into water vapor.
• Water vapor is also added to the atmosphere by transpiration. Transpiration is the release of water by plants. Plants collect water through their roots and lose it as it evaporates into the atmosphere through small openings on the undersides of their leaves.
• When water vapor cools, it condenses. We can see the condensation of water in the form of clouds. We can also see condensation whenever water vapor comes in contact with cold air or cooler objects.
• Water vapor condenses when it reaches higher elevations because the air is cooler.
• When water returns to the Earth, it can be absorbed into the soil. This process is called percolation. Water will trickle through the tiny spaces between the soil particles. This water is called ground water.
• Ground water can move to lower elevations and depression through underground rivers.
• Precipitation that falls on the ground or on the surface of bodies of water can once again evaporate, starting the water cycle over again.
• The water cycle is an essential part of the natural system and is vital to all living things. Without the continuous return of fresh water to the land, land plants and animals could not exist.

More on water cycle

Activity sequence

1. Transpiration
2. Condensation
3. Percolation
4. Absorption
5. Condensation
6. A water cycle

Activities

Activity 1. Transpiration

Materials

Desktop lamp, two clear plastic cups, spinach with stem and leaves, index card, scissors, water 

Outcome

Observe and explain that the leaves transpire water, and that air contains water.

Procedure

1. With scissors make a slit to the center of the index card. Fill one cup half way with water.
2. Insert the spinach through the slit in the index card with the leaves above the card, and place stem side of spinach in water.
3. Place other cup upside-down so that the spinach leaves are completely enclosed in the cup.
4. Place under lamp.
5. In three to four minutes observe the water condensation collecting on the inside of the top cup.
6. Discuss and conclude the outcome

Activity 2. Condensation

Materials

five frozen water balloons, container , paper towels 

Outcome

Observe and explain that water changes from vapor to liquid when warm air touches a cold object.

Procedure

1. Put water into balloons and freeze over night.
2. Half fill the container with water which is a safe degree of hot.
3. Have learners feel the balloon to notice they are frozen and cold.
4. Have learners set the balloon in the container.
5. While learners are waiting have them predict what they will see.
6. Wait three to four minutes, and ask learners to pick up the balloon to observe what is forming on it.
7. Have learners place the balloon over a paper towel to observe the rain coming from the balloon.
8. Ask where the water is coming from.
9. Observe and explain.

Activity 3. Percolation

Materials

One 2 liter pop bottle, two clear plastic cups, small coffee filter, small pebbles, sand, dirt, water.

Outcomes

Learners will observe and explain how pebbles, dirt and sand act as a natural water filter for dirty water.

Procedure

1. Cut bottom off of pop bottle.
2. Place coffees filter in the spout end of the bottle, and place this end in a clear plastic cup.
3. Pour pebbles on the filter, followed by sand and dirt.
4. Mix water and some of the dirt in the cup.
5. Pour the dirty water through the filter.
6. Observe and explain the outcomes.

Activity 4. Absorption

Materials

Clear plastic cup, blue or red food coloring, stalks of celery with leaves, water, paper towels, ruler 

Outcomes

Learners will observe and explain water absorption in a celery stalk.

Procedure

1. Mix food coloring and water in a clear plastic cup till the color of the water is dark than the celery.
2. Remove two centimeters from the bottom of the celery stalk .
3. Place the celery stalks with leafy side up in the colored water.
4. Every five minutes cut a centimeter off of the bottom of celery and display on the paper towel the row of small circles in the celery outlined by the colored water.
5. Observe and explain the outcomes.

Additional exploration

Slice a celery stalk, with leaves from the bottom up three to four inches and insert one side into one color of food coloring water and the other side into a different color of water and let stand till the food colored water fully enters the leaves.

Activity 5. Condensation development

Materials

2-liter plastic bottle, warm water.

Procedure:

1. Fill the bottle three-fourths full of very warm water, quickly cap the bottle, gently squeeze and release the bottle.
2. You should see a cloud.
3. Squeeze to see how pressure affects clouds.
4. If the bottle gets foggy shake the bottle to clear the fog.
5. If you can’t see a cloud you may want to use a flashlight.
6. You may also want to add some dust or smoke from a match.
7. Try all these again with the bottle one-fourth filled with water.
8. Observe and explain the outcomes.

Activity 6. A water cycle environment

Materials

Container with lid, plants, shell of water, soil, sand, small rocks.

Outcomes

Learners will explain a water cycle

Procedure

1. Put rocks in the bottom of the container, next sand, then soil, plant plants, water and put the lid on.
2. Put the jar in a sunny place and see how the water cycle works.
3. To adjust the water add more or leave the lid off.
4. Observe and explain the outcomes.

Top

Dr. Robert Sweetland's notes
[Home: homeofbob.com & thehob.net ]