How to Build a Temperature Sensor
A temperature sensor is a device that measures temperature and is more commonly known as a thermometer. Thermometers rely on a variety of specific mechanisms but one of the simplest types is a fluid thermometer. Fluid generally expands as it gets hotter and this expansion may be measured to determine the temperature. You can make a simple fluid thermometer from common household items.
Things You'll Need
- Water
- Rubbing alcohol
- Food coloring
- Jar (thin and narrow)
- Nail
- Hammer
- Clear drinking straw
- Modeling clay
- Commercial thermometer
- Marker
- Cardboard
Instructions
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1
Make a solution with equal amounts rubbing alcohol and water. Add a few drops of food coloring and mix thoroughly to turn the solution a bright red. Fill a thin, narrow jar with the thermometer fluid until it is about 1/4 full. Locate a nail that is slightly larger than the clear drinking straw you will be using later. Punch the nail through the center of the jar's lid with the hammer.
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Screw the lid onto the jar and push the straw through the hole in the lid. Adjust the position of the straw so the bottom end of the straw is below the fluid's surface but does not touch the bottom of the jar. Place a piece of modeling clay around the hole in the jar's lid. Ensure that the clay forms a watertight seal with the straw and holds the straw straight up.
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3
Calibrate your thermometer against a commercial thermometer. Place a piece of cardboard next to your thermometer and mark the fluid's position in the straw on the cardboard. Do this for at least two different temperatures. Use these marks to make a temperature scale for your thermometer.
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