Wind Chill!!!

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Hook
In this activity you will experiment with temperature changes due to evaporation versus temperature changes due to evaporation enhanced by wind.

Materials

Procedure
Hypothesis: Predict how the temperature of a small amount of water on the temperature probe would change in a two minute period.

What if your temperature probe was exposed to the wind? What would be the impact of the wind on the graph you have drawn above. Draw another line representing the affect of wind. Label your axes and your lines.

Procedure For Testing Your Hypothesis: 1. Wrap two temperature probes (or two thermometers) with square pieces of filter paper secured by small rubber bands. Roll the filter paper around the probe tip in the shape of a cylinder.

Hint: First slip the rubber band up on the probe, wrap the paper around the probe, and then finally slip the rubber band over the wrapped paper. The paper should be even with the probe end.

2. Use the CBL to set up a time graph to measure the cooling rate of the two probes as the water evaporates. If using thermometers, use string to secure the two thermometers to a ring stand, monitor the temperature and time with a stopwatch and graph your results.

3. Start data collection with the two probes in a beaker of water, then remove them from the beaker and hold one probe stationary and swing the other gently in the air.

4. If using thermometers, use string to secure the two thermometers to a ring stand, monitor the temperature and time with a stopwatch and graph your results Fan one thermometer with an index card, while the other thermometer has no wind.

5. Compare the two graphs. Draw the graphs below. Label the axes and graphs.

Discussions Questions/Extensions ......
1. What did the graphs look like? Describe them in words.

2. What was the effect of the wind on the temperature?

3. What variables affected their graphs?

4. Why are these graphs cooling graphs not heating graphs?

5. What might happen if you did a similar experiment with an alcohol instead of water?

6. Why do polar researchers take the temperature and wind chill so seriously? What causes frostbite and hypothermia? How might wind chill influence the onset of these conditions? What precautions might prevent these conditions?

7. Investigate how wind chill charts are made by using some of the internet sites in the backgroun information and resources. Examine the variables in the NWS wind chill equation. What variables impacted student experiments.

8. Investigate Paul Siple’s experiments in Little America, Antarctica on wind chill.

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