Thermal Energy

Thermal Energy

Matter is made of particles that are in constant random motion

The faster the particles move, the warmer an object gets

Kinetic TheoryThis is the basis of Kinetic

Theory

Temperature

Temperature is the measure of average kinetic energy of an object

Temperature and energy are directly related

The more kinetic energy, the higher the temperature

The more potential energy, the lower the temperature

Temperature

The standard unit for temperature is Kelvins (K)We also use Celcius and

FarenheitKelvin -273 = ˚C

Why does the ice melt?

Thermal Energy

The total of the Kinetic Energy and Potential Energy of all particles in an object.

Thermal energy and temperature are directly related

Thermal energy and mass are directly related

Thermal Energy and Mass

Heat

Thermal energy that flows from something at a higher temperture to something at a lower temperature is called heat

Heat is measured in Joules (J)An example is when you get up from

a chair and it is warm to the touch. In science, ther is no cold, only

absence of heat

Specific Heat

Specific heat is the amount of heat needed to raise 1 kg of a substance 1 ˚C

It is measured in J/kg ˚C

 

SubstanceSpecific Heat

Capacity  at 25oC in J/goC

H2 gas 14.267He gas 5.300H2O(l) 4.184

ethyl alcohol 2.460 air 1.020

magnesium 1.020 nickel 0.440 zinc 0.39

copper 0.385 brass 0.380 sand 0.290 silver 0.240

tin 0.21 lead 0.160

mercury 0.14 gold 0.129

Specific Heat

Water has a very high specific heat.

It is good as a coolant in radiators

Formula for Change in Thermal Energy

The formula for thc change in thermal energy is Q = mCΔTQ – the change in thermal energyM – mass of the objectC – specific heat of the substanceΔT – change in temperature (T

final – T initial)