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Wind-chill experiment
Here's how you can test whether water will freeze with an
ambient temperature of 35° F (2° C) and a wind chill factor of 25° F (-4° C).
First, you need a fan since it takes a 15 mph (24 kph) wind to produce a wind
chill factor of 25° F if the air temperature is 35° F.
- Empty the refrigerator
(ideally) or put the food on one shelf to
allow air flow. Take out any glass shelves or shelves that block air
flow.
- Set the frig to 35°; put a
check thermometer in.
- Set a pan of water on the
middle rack.
- Place a small battery-powered fan on the top shelf
pointed at the pan of water. A link for a $14 battery-operated fan is
given below.
- Estimate the air speed
from the fan onto the water by feel with your hand. Close the frig door as
much as possible on your arm while estimating the air speed. You probably
can guess that the air speed is, say, somewhere between 5 mph
and 20 mph with some confidence.
- Calculate or look up the
wind chill factor associated with your air speed estimates and refrigerator
temperature. A link for a lookup table is given below.
- Stick a thermometer in the
pan of water.
- Check the temperature of
the water until it reaches about 35°.
- Leave the experiment going
overnight to see if the water ever freezes.
Good luck!
NOAA: National Weather Service wind chill chart
Safety Central: $14-battery operated fan
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