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3rd 6 Weeks test Study Guide
Test on Tuesday Dec 13th
TOPICS:
Potential and Kinetic Energy
“MRS. CENT”
Energy Transformations
Thermal Energy and Heat Transfer
Thermal Equilibrium
POTENTIAL AND KINETIC ENERGY
 Potential Energy: Stored energy an object has because of position or condition.
 Kinetic Energy: The energy of motion
 The higher the object the more gravitational potential energy it has. The lower the object, the less
potential energy it has.
 Just before an object falls = potential only. As an object is falling = both kinetic and potential
energy, but kinetic is increasing and potential is decreasing as it gets closer to the ground.
MRS. CENT
 Mechanical Energy: The total potential and kinetic energy in a system, motion energy. Energy of
motion and position.
 Radiant Energy: Energy carried by electromagnetic waves, like light, microwaves, radio waves.
 Sound Energy: Energy produced by sound vibrations (waves of pressure)
 Chemical Energy: Energy stored in the chemical bonds of molecules and released during a
chemical reaction. Food, batteries, fuel.
 Electrical Energy: The energy generated by moving electrical charges. Electricity.
 Nuclear Energy: Energy stored in the nucleus of an atom.
 Thermal Energy: The energy of motion in the molecules of a substance.
ENERGY TRANSFORMATIONS
 Law of Conservation of Energy: Energy cannot be created or destroyed, but it can transform.
 There is always the same amount of energy in the universe! It doesn’t disappear…it just changes.
 Example: How does energy transform in a hair dryer?
o Electrical  mechanical and heat and sound
 Example: How does energy transform in a flashlight:
o Chemical energy  electrical energy  light energy
 Can you think of more examples?
THERMAL ENERGY/HEAT TRANSFER
 Thermal Energy: The energy of motion in the molecules of a substance
 The faster the molecules are moving, the warmer a substance is
 Conduction: The transfer of heat from one object touching another (direct contact). Examples: Hot
soup warming up a metal spoon, chocolate melting in your hand, straightener or curling iron
warming your hair, hot iron pressing your clothes.
 Convection: The movement of heat in liquids and gases. Examples: Hot air blowing out of the
heater vents and warming your house, hot air balloon rising, water boiling, currents flowing in hot
liquid layer of earth’s mantle
 Radiation: The direct transfer of energy through empty space by electromagnetic waves.
Examples: Sunlight, fire, wood-burning stove or fireplace warming a room, heat lamps, infared
space heaters.
THERMAL EQUILIBRIUM
 Thermal Equilibrium: Heat flows from a warmer matter to colder matter until the two substances
reach the same temperature. Heat transfer is really neat! It always goes from hot to cold, from
HOT to COLD! 
 Example 1: Cold object sitting in a warm room. Heat will flow from the warm air to the cold
object, warming it up until everything reaches room temperature.
 Example 2: Hot object in a cooler room. Heat will flow from the warm object to the cooler room
until everything reaches room temperature.
HINTS
 Make sure you know the meanings of all your vocab words and can identify examples of each.
 Make sure you can identify the energy transformations taking place in examples.
 Make sure you can identify examples of conduction, convection, and radiation heat transfer.
 Make sure you know that heat will ALWAYS move from the warmer matter to the cooler matter
until everything has reached the same temperature.
 Study and quiz yourself.