Download Heat Energy - Waconia High School

CHAPTER 15
Energy: Forms and
Changes
Nature of Energy
 Energy is the ability to do work.
–Measured in Joules
–Objects gain energy when work is
being done on them.
–Objects use energy to do work.
 There are 5 forms of energy:
1. Mechanical 2. Heat 3. Chemical
4. Electromagnetic 5. Nuclear
Mechanical Energy
 Energy of Motion
 Examples: Sound, walking,
rivers, oceans, riding a bike, a
plane flying, etc….
Heat Energy
 All matter is made up of tiny particles
called atoms.
 Heat energy is the motion of atoms.
 The faster the atoms move, the more
heat that is produced.
 Causes a temperature change or phase
change
Heat Energy
Phase Change:
Solid
Liquid
Example: Water
Ice
Water
Ice + heat = Liquid
Gas – heat = Liquid
Gas
Gas
Water + heat = Gas
Water – heat = Solid
Chemical Energy
 Stored in chemical bonds.
 Energy is released when the bonds
break.
Example: Water (H2O)
Breaking water into H & O will cause
a release of chemical energy.
Electromagnetic Energy
 Moving electrical charges
 Examples: Power lines,
electricity, light, lasers, X-rays,
radio waves.
Nuclear Energy
 Stored in the nucleus of atoms
 Released when atoms are split or when
nuclei (more than one nucleus) fuse
together.
 The most concentrated form of energy.
(meaning there is a lot of energy in a
small amount of space)
Potential Energy
 How much energy there could be.
* Also called the energy of position
 Objects with potential energy are not doing
work. They are storing energy in order to do
work.
 Ex. A rubber band has potential energy. A
stretched rubber band has even more
potential energy!
Gravitational Potential Energy
 Is potential energy that is dependent
upon height.
 G.P.E. = Weight x Height
Ex. Standing on a 1-m high diving board
gives you GPE, but standing on a 3-m
high diving board gives you 3 times the
amount of GPE.
Kinetic Energy
 The energy of motion
 The faster and object moves, the more
kinetic energy is has.
 Kinetic energy depends upon the mass
and velocity of the object.
K.E. = mass x velocity2
2