IPS Lab 3.1 Measuring Temperature: Calibrating a Thermometer

A thermometer with no numbers is calibrated (numbers are assigned).  The thermometer is placed in water with ice cubes.  After the red liquid stops moving down, the location is marked as zero.  The thermometer is placed in boiling water. After the red liquid stops moving up, the location is marked as 100^oC.  Thg thermometer is used to measure other temperatures as well.  Numbers are placed on the thermometer by measuring the distance from 0 to 100 and dividing this distance into ten equal parts.  Measuring up from the zero this 1/10 distance is marked as 10 degrees then 20 degreees until 90 degrees is reached.

Temperature is defined as the average kinetic energy (KE) of the particles.  In unit one, we developed a model of kinetic energy.  Objects have kinetic energy due to their motion.  The equation for kinetic energy is 1/2 mv².  The average part of this definition reflects the fact that the particles are NOT all moving at the same speed.  Some are moving faster and some are moving slower.  The temperature reflects the average kinetic energy of the moving particles.

How does the thermometer measure the temperature?

• When a cold thermometer is placed in hot water, heat is transferred from hot to cold. 
• The hot water particles have more kinetic energy than the cold thermometer particles. 
• Hot water particles collide with the thermometer and transfer KE.
• This makes the red liquid particles move faster.
• The red liquid particles collide with each other more.
• The red liquid particles push it each other farther apart.
• The red liquid expands and move up the thermometer.
• The red liquid stops moving up when the temperature is the same as the hot water.