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Procedure:
Listed below are several science projects you can perform using a conventional, digital or infrared thermometer. First, become familiar with the operation of the various kinds of thermometers and the Fahrenheit and Celsius temperature scales.
The temperature of the air and everyday objects is usually given using the Fahrenheit or Celsius scale. In the Celsius scale, ice is 0 degrees and boiling water is 100 degrees (at sea level). In the slightly older Fahrenheit scale, ice is 32 degrees and boiling water is 212 degrees. Scientists and people in most countries use the Celsius scale. While the Fahrenheit scale is going out of style, its advantage is that it provides nearly twice the resolution of the Celsius scale. Both Celsius and Fahrenheit scales are used in the projects that follow.
Here are the formulas for converting between Celsius (TC) and Fahrenheit (TF):
Celsius (TC) = (5/9) x ( (TF) - 32)
Fahrenheit (TF) = (9/5 x (TC)) + 32
Here are spreadsheet formulas you can use for making these conversions:
Various online calculators like this one allow you to convert from Fahrenheit to Celsius or Celsius to Fahrenheit.
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Project Ideas:
You can use both conventional and infrared thermometers to learn much about temperature islands. Always use care when using a thermometer outdoors, in public places and around strangers. Be careful to avoid touching objects that are so hot they might burn you. Here are some projects you can try:
1. Measure Outdoor Temperature Islands With an IR Thermometer.
You can use an infrared thermometer to quickly measure the temperature of a wide variety of temperature islands. The temperatures in the following spreadsheet were measured in and adjacent to a grassy field in Central Texas on a bright, sunny day. With the exception of the first fence post, all temperatures were measured with the object in direct sunlight.
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DATE: 22 September 2008 |
SKY CONDITION: Bright sun with a few cumulus clouds |
| TIME |
OBJECT |
TEMPERATURE |
17:05 |
Shaded wood fence post |
88F/31C |
17:06 |
Hackberry tree in full sun |
91F/33C |
17:07 |
Straw on ground |
106F/41C |
17:08 |
Grass |
81F/27C |
17:09 |
Sunny wood fence post. |
114F/46C |
17:10 |
Brick |
110F/43C |
17:11 |
Weathered wood plank |
114F/46C |
17:12 |
Rusty steel |
112F/44C |
17:11 |
Concrete |
110F/43C |
17:14 |
Asphalt road |
107F/42C |
17:13 |
Unpainted mail box (inside) |
98F/37C |
17:13 |
Unpainted mail box (outside) |
114F/46C |
17:14 |
Black mail box (inside) |
106F/41C |
17:14 |
Black mail box (outside) |
145F/63C |
17:15 |
Tractor muffler |
764F/407C |
17:21 |
White T Shirt on man |
92F/33C |
17:21 |
Black T shirt on man |
117F/47C |
Here's a graph that shows all the data (in Celsius) in the table above with one exception:
 Click to view enlarged version.
Look carefully at this graph. What do you see? Clearly, things made by people are much warmer than grass and the tree. What is the hottest object in the graph? What does this suggest about cars that are painted in dark colors? Think about what this means for the temperature in a town or city. Notice the difference in the temperatures of the white and black T shirts worn by two men in the same location. While a black T shirt can become very hot on a summer day, it might be ideal for a cool day. Now look at the next graph--which includes the temperature of the tractor muffler.
 Click to view enlarged version.
The tractor muffler is installed between the engine and exhaust pipe. The hot gases from the engine pass through the muffler, which softens the sound of the explosions that occur inside the engine's cylinders. As you can see in the graph and table, the muffler is very hot! In fact, it is more than six times hotter than the outside of the black mailbox.
Project: Use a computer to make a simple spreadsheet like the one above or draw a similar spreadsheet on a sheet of paper. Place your spreadsheet on a clipboard and take it and an IR thermometer outdoors to measure the temperature of a variety of natural things and objects made by people. If possible, measure the same things at several times of day on a clear day and an overcast day. Graph your results and explain them.
2. Measure Indoor Temperature islands With an IR Thermometer.
The temperature inside a class room, work place, apartment or house may seem relatively constant. Whether the overall temperature seems too warm or too cool, it usually seems fairly uniform unless you are near a heater or air conditioner vent. Actually, there are many temperature islands inside buildings, and most of them are warmer than the air inside air conditioned buildings.
The table below lists temperatures measured inside a residential house on a pleasant fall day. The temperatures were measured by placing the sensitive region of an IR thermometer close to the object.
DATE: 23 September 2008 |
PLACE: Temperature inside residential house |
| TIME |
OBJECT |
TEMPERATURE |
09:50 |
Floor |
74F/23C |
09:50 |
Ceiling |
75F/24C |
09:52 |
Fluorescent lamp |
100F/38C |
09:52 |
Night light (incandescent) |
82F/28C |
09:53 |
Computer |
80F/27C |
09:55 |
Iron | 345F/174C |
09:57 | Coffee pot |
166F/74C |
09:57 |
Coffee in cup |
125F/52C |
09:59 |
Cold water |
73F/23C |
09:59 |
Hot water |
109F/43C |
10:00 |
Freezer |
1F/-17C |
10:09 |
Coil light 1 |
122F/50C |
10:09 |
Coil light 2 |
135F/57C |
10:13 |
Air conditioner: Inside |
62F/17C |
10:14 |
Air conditioner: Outside |
110F/43C |
10:31 |
Person 1 (shoulder) |
87F/31C |
10:31 |
Person 2 (shoulder) |
88F/31C |
Project: Use a computer to make a simple spreadsheet like the one above or draw a similar spreadsheet on a sheet of paper. Place your spreadsheet on a clipboard and take it and an IR thermometer on a tour of a classroom, school, apartment house or other indoor place. Measure the temperature of things like those listed in the table above and anything else that may be a temperature island. Caution: Use care when measuring the temperature of objects that are very hot. Your results may be very different than those given above. Why?
You can specialize in measuring the temperature of particular objects. For example, consider measuring the temperature of the arm or shoulder of a dozen or more people. (Always ask permission and explain what you are doing.) What is the temperature difference between exposed skin and skin covered by clothing? Are there noticeable differences when measuring the temperature of different kinds or colors of fabric? Are children warmer or cooler than adults? People tend to emit about 100 watts of power each, which explains why a room full of people can soon become uncomfortably warm.
3. Measure Temperature During a Nature Walk.
You can learn much about natural temperature islands by taking a walk in a park or other natural area. For this project, a short walk was made from the sunny field measured above to a creek about 380 meters (1,250 feet) away. The temperature was measured by pointing an IR thermometer at the vegetation along the trail and the water in the creek. A conventional or digital thermometer can also be used if the bulb or probe is shielded from direct sunlight.
DATE: 22 September 2008 |
SKY CONDITION: Bright sun with a few cumulus clouds |
| TIME |
OBJECT |
TEMPERATURE |
18:39 |
Shade under forest canopy |
84F/29C |
18:42 |
Shady gully 4 m (12 ft) deep |
77F/25C |
18:43 |
Shade under forest canopy |
82F/28C |
18:44 |
Shady meadow |
79F/26C |
18:46 |
Geronimo Creek |
74F/23C |
Notice the significant drop in temperature along the trail to the creek, a difference that was obvious even without a thermometer. These data were collected in late afternoon. The temperature difference is less when the sun is high in the sky.
Project: Use a computer to make a simple spreadsheet like the one above or draw a similar spreadsheet on a sheet of paper. Go on a nature walk and measure the temperature along the way. For best results, begin in a parking lot or field so you can see the contrast between the natural area and where the landscape has been transformed into a parking area.
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Click to view enlarged version.
Click to view enlarged version.
