Thermal Energy
• All matter is made of particles.
• These particles are always moving.
• The more energy these particles have the more
agitated they will be.
Least Energy
Medium Energy
Most Energy
Thermal Energy
• This energy contained in the moving particles is
called thermal energy.
• How could I increase the thermal energy in this
container?
1) Increase the number of
particles
2) Increase the temperature.
What will happen here?
1) The ice will melt
2) The person will feel cold
Why???
1. Heat is transferred from the hand to the ice.
2. Since the hand is losing heat, the person feels cold.
3. Since the ice is gaining heat, it melts.
1) Heat is transferred from the hand to the ice.
• Heat is the transfer of thermal energy between
two environments. Q = ∆Et
Q =heat (in J)
∆ = variation
Et = Thermal energy
• Heat always passes from the warmer to the
cooler environment.
HOT
COLD
2) Since the hand is losing heat, the person feels cold.
• Only heat can be transferred between two objects.
• When you feel cold, you simply are feeling a lack
of heat.
• Molecularly, when an object loses heat, it is
losing thermal energy and so the particles
slow down.
• In the case of a gas, if the particles slow down too
much it will become a liquid. A liquid will become
a solid.
3) Since the ice is gaining heat, it melts.
• When the ice gains heat, the thermal energy of
the particles increase.
• This causes the particles to spread out and
eventually turn into liquid.
+E
+E
Heat vs. Temperature
Temperature: The measure of the agitation of
the particles of a substance.
Heat: The energy of the particles, which depends
on the degree of agitation as well as the number of
particles.
Heat vs. Temperature
If the water in the bathtub and the pot is 1000 C, which
contains the most heat?
If the water in the bathtub is 600 C and the pot 1000 C, which
contains the most heat?
Are Heat and Mass Related?
• Which will heat up faster? (Both the same substance)
Why?
Are Heat and Nature of the substance
related?
• Which will heat up faster? (Both the same mass)
It depends on the specific heat
capacity of each substance.
Measuring Heat and Temperature
• How do you measure temperature?
Using a thermometer.
• How do you measure Heat?
Using a thermometer and an equation.
Q = mcΔT
Homework: p.39 to 41
• LAB REPORT DUE FRIDAY!