pt

							     Gay-Lussac’s Law

Identifying the Relationship between
     Temperature and Pressure
              Introduction
• Why do tires on 18-wheel trucks explode on
  long summer trips?
• Think about the temperature of the air.
• Think about the contact between the tires
  and road.
                 Key Concepts
• “Temperature is the         • “The pressure of a
  measure of the                gas is the force of its
  average energy of             outward push
  particles of                  divided by the are of
  substance.”                   the walls of the
• Greater energy results in     container.”
  greater particle motion.    • Pressure is the outward
  This corresponds to an        push that a gas exerts on
  increase in temperature.      the walls of a container.
              Hypothesize
• An increase in temperature causes an
  increase in pressure. This increase in
  temperature can cause tires to explode.
• How would a decrease in
  temperature affect the tire pressure?
               Exploration
• In this activity, you will use instruments to
  determine the relationship between gas
  temperature and pressure.
• You will accomplish the exploration using
  the TI Voyage calculator, TI Calculator-
  Based Laboratory (CBL2), gas pressure
  sensor, and temperature sensor.
TI Voyage Calculator
Calculator-Based Laboratory 2 (CBL2)
Stainless Steel Temperature Sensor
Gas Pressure Sensor
             Student Roles
• The reporter writes down all of the
  temperature and pressure value that are
  obtained during the experiment.
• The temperature analyst is responsible for
  the temperature sensor. This analyst hold
  the black part of the sensor and keeps the
  metal part in the water at all times.
      Student Roles Continued
• The pressure analyst is responsible for the
  the pressure sensor and the glass test tube.
• The technician is responsible for operating
  the calculator. The technician also adds ice
  to the water and stirs the water.
                  Procedure


• Turn on the calculator
  by pressing [ON].
                Procedure


• Type datamate().
• Press [ENTER].
                         Procedure
Insert the
stopper.

        • Insert the rubber stopper into the test tube.
        • Make sure that the air valve is open.




The valve
is open.       stopper
Procedure
 open
 valve



    closed
     valve
              Procedure
                                    real-time
                                    temperature
                                    and pressure
                                    data




Record the real-time temperature and pressure
  data from the main screen of the DataMate
  program.
                    Procedure
                           test tube/rubber stopper

• Submerse the test
  tube/rubber stopper
  into the water.
• Do not allow the water
  to touch the rubber
  stopper.

   temperature sensor
               Procedure




• Allow the temperature and pressure readings
  to stabilize.
• Record the temperature and pressure values
  from the upper right corner of the screen.
                     Procedure

• Add ice to the water
  and stir.
• Allow the ice to
  completely melt.
• When the ice has
  melted, allow the the
  data values to
  stabilize and record
  the values.
                Procedure
                               DATA TABLE
                      Temp. (C)        Pressure (kPa)


• Continue adding
  ice, allowing the
  pressure and
  temperature
  values to
  stabilize, and
  recording the
  values.
              Observation
• Analyze the temperature and pressure data
  in the Data Table.
• What happens to the pressure when the
  temperature decreases?
• Does this observation support or disprove
  your hypothesis?
 Applications of Gay-Lussac’s Law

• Tires bursting due to high temperatures
• Pressure cookers
• Autoclave  Medical industry sterilization
  with water vapor under pressure