Air Temperature and the Water Cycle Some places on Earth have more rain than others. Some places have almost no rain at all. Other places have snow. How much precipitation a place gets helps determine its climate. Precipitation is one process of the water cycle. So how does the water get into the air to form rain or snow? The Sun provides the energy that drives the Earth’s water cycle. The Sun’s energy warms the Earth’s atmosphere and it warms the water in Earth’s oceans and lakes and the land, too. The water in the lakes or oceans evaporates (turns into water vapor, a gas) into the air. Evaporation is another process of the water cycle. In this investigation you explore how the temperature of the atmosphere, the air, affects the water cycle. This investigation takes 4 days (96 hours) to complete with one tank. What you need: You need to build a neighborhood in a fish tank. You will use the tank twice, one time without the “Sun” and one time with the “Sun”. Using a tank with a cover keeps the air and the water in the tank from escaping. For a basic tank: · Small fish tank with a cover. Plastic covers are a fire hazard and not recommended. Plastic wrap is not recommended for the same reason. Use heavy aluminum foil wrapped around the lamp (see Tank 2 diagram on page 2), but be careful, the foil and the lamp will get hot. · Lamp with a 60w bulb. A clamp lamp or a desk lamp will work. · Thermometer · Water at room temperature. You can add a drop of blue food coloring to the water if you want. · Clock · Student worksheet (see below) For a tank like the one in the diagram*, you will also need: · Water resistant modeling clay (florist clay) · Plastic houses, people, cars, etc. · Be sure to have an “ocean” beach on one end of your tank. *Not adding the people, houses, cars, etc. will not affect your results. Tank Set-Up:

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What you do: · Build your neighborhood tank. · Tape the thermometer to the inside of the tank with the numbers facing out. · Complete Part I & II of the investigation. Part I: “Sun” Off · Add enough water to the tank to bring the water level to 1 inch in the “ocean end” or the entire bottom of the tank. · Cover and seal your tank. · Record the temperature of the air in the tank in the Tank 1: “Sun” Off table of your worksheet · Make a drawing of what the tank looks like on your worksheet. · Wait 1 hour and record the air temperature in the Tank 1: “Sun” Off table of your worksheet. · Make a drawing of what the tank looks like on your worksheet. · After 24 and 48 hours record the air temperatures in the Tank 1: “Sun” Off table of your worksheet. · Make drawings of the tank on your worksheet. Part II: “Sun” On · Add enough additional water to the tank to bring the water level in the bottom back up to 1 inch. · Cover and seal your tank. · Record the temperature of the air in the tank in the Tank 1: “Sun” On table of your worksheet · Make a drawing of what the tank looks like on your worksheet. · Wait 1 hour and record the air temperature in the Tank 1: “Sun” On table of your worksheet. · Make a drawing of what the tank looks like on your worksheet. · After 24 and 48 hours record the air temperatures in the Tank 1: “Sun” On table of your worksheet. · Make drawings of the tank on your worksheet. Use your observations and graphs to answer the questions on your worksheet.

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Air Temperature and the Water Cycle Name __________________________________________ Part I: “Sun” Off – Tank 1

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______ºF

-

______ºF

=

______ºF for “Sun” Off

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Part II: “Sun” On - Tank 2

5

______ºF

-

______ºF

=

______ºF for “Sun” On

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Air Temperature and the Water Cycle Questions: 1. What was the total temperature change for Tank 1: “Sun” Off? _____ 2. What was the total temperature change for Tank 2: “Sun” On? _____ 3. Which tank reached the highest temperature, Tank 1 or Tank 2? ______ 4. Which tank heated up the fastest, Tank 1 or Tank 2? _____ 5. Describe the differences you observed between Tank 1 and Tank 2 after 24 hours.

6. Describe the differences you observed between Tank 1 and Tank 2 after 48 hours.

7. Describe the difference in evaporation and precipitation you observed between Tank 1 and Tank 2.

8. Explain what you think caused those differences.

9. When do you think most of the water evaporates from the Earth’s surface, during the day or during the night? Why do you think that?

10. You observed the effect air temperature has on how fast water evaporates and forms precipitation (condenses) in a coastal climate (a place near the ocean or a large lake). What do you think would happen if you put sand in the tank instead of water? Why do you think that?

11. What do think would happen if you covered everything in the tank with snow or ice? Why do you think that?

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