Absolute Zero
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Student Handout
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Calibrating Your Thermometer
Now that you have made your
thermometer, it's time to calibrate it with a thermometer that includes a
scale. The two most commonly used scales are Fahrenheit and Celsius, which were
invented in the early to mid-1700s by scientists named Daniel Fahrenheit and
Anders Celsius.
Procedure
Create your
ice-water bath by filling half your beaker with water and crushed ice. Make
sure that there is enough ice in the beaker to chill the water but not so much
that you cannot set your thermometer in the beaker. Put your
bulb thermometer and reference thermometer in the container of ice water so
that it is mostly—but not fully—submerged in the ice water. When
the liquid in the your thermometer stabilizes (it takes about five minutes),
mark the index card next to the height of the liquid and label it "ice
water." Write the temperature on the reference thermometer next to this
mark. Move both
thermometers to the warm water bath. Once again mark the appropriate spot on
the index card when the liquid in your thermometer stops moving (it takes about
ten minutes). Write down "warm water" and the temperature from the
reference thermometer next to this mark. Draw a line
halfway between the two spots and label it with the number halfway between your
high number and low number. Continue to add a few extra lines in this way: Mark
a spot halfway between two other lines, and label it with a number halfway
between those two numbers. Look at the
scale that your reference thermometer uses and mark the card above your
measurements with that scale (°C for Celsius and °F for Fahrenheit).
Convert the temperatures you measured from one scale to the other using one of
the formulas in the "Conversion Formulas" sidebar. Write the second
set of temperatures on the opposite side of the index card and label that
scale.
Conversion Formulas
Celsius to Fahrenheit
Multiply the
Celsius temperature by 9. Divide the answer by 5. Add 32.
Fahrenheit to Celsius
Subtract 32 from the Fahrenheit number. Divide the
answer by 9. Multiply by 5.
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