An official website of the United States government

# Water World Classroom Lesson: Optional Hands-on Activity

This hands-on activity is part of the Water World Classroom Lesson.

Water World Classroom Lesson: Optional Hands-on Activity

Objective: To discover that water can move between locations and states of matter but does not disappear (leave the system).

Materials:

• A glass or plastic container

• A tight lid or plastic wrap that can be stretched over the top of the container

• Soil

• Small rocks

• Water

• Small cup or bowl

• Modeling clay

• Kitchen scale or balance

• Watering can or spray bottle

Procedure:

1. Add soil and small rocks to the container. Create a landscape with a slope in the soil. Create a landscape with a slope in the soil. Make at least one small lake or pond (to prevent water from seeping out, line it with plastic wrap or modeling clay) and at least one channel to model parts of the water cycle.

1. Weigh the container, lid, or plastic covering included, prior to adding water.

1. Weigh the water or the entire system after water has been added (see #5). Subtract weight of the container to find the weight of the water.

1. Record weight data on the data sheet.

1. Add water to the system:

• If you have a pond, place some water carefully in the pond.

• Simulate rain by sprinkling with watering can or spraying with spray bottle. NOTE: You may lose water with this method. So, if you are spraying, weigh the entire system after adding water.

• Once you have distributed all the water, put the airtight top or plastic wrap over your system.

1. Take photographs and/or record your observations in the data table.

1. Decide on a research question to ask/answer and set up as needed (see Observation Data Sheet).

1. Place the system in warm area – near a heater or radiator, or on a heating pad set to low (it is a good idea to place a towel between the system container and the heating pad).

1. Leave the system for at least two hours.

1. After time has elapsed, weigh the entire system and record your data and observations.

1. Place the system in cold location; refrigerator or even freezing, if desired. Leave for at least two hours.

1. Add situations as desired to test individual research questions or write down your conclusions.

 Date Conditions Mass Change Evidence of Water?

Questions:

1. At the beginning of the experiment, you added water to the system that “disappeared” into the soil. In a real ecosystem, like the one in which you live, do you think there is water under the surface of the ground? Explain your thinking.

2. Do you think it is possible for water that is underground to come up to the surface? Explain your thinking.

3. Did you see any evidence of this between the heating and cooling times? If so, what did you observe?

4. When you heated the system, you may have seen drops of water up at the top of the system. What do you think happened? Explain your thinking.

5. Was there any change in mass (weight) between days when the lid was closed? If so, explain why you think there was a change.

6. If you opened the lid to your container, what changes did you notice? Why do you think this happened?

7. What did you see in the system that is like weather outside?

8. On Earth, the total amount of water does not change much, although water continuously moves through the different elements of the water cycle. Thinking about your experiment and ecosystem, explain what this means about whether Earth is considered as a closed system or an open system.