Big Idea 11:Energy Transfer and Transformations

A. Waves involve a transfer of energy without a transfer of matter.

B. Water and sound waves transfer energy through a material. C. Light waves can travel through a vacuum and through matter. D. The Law of Conservation of Energy: energy is conserved as it transfers from one object to another and from one form to another.

Benchmark Number & Descriptor

SC.7.P.11.1 Recognize that adding heat to or removing heat from a system

may result in a temperature change and possibly a change of state.

SC.7.P.11.2 Investigate and describe the transformation of energy from one

form to another. SC.7.P.11.3 Cite evidence to explain that energy cannot be created nor

destroyed, only changed from one form to another. SC.7.P.11.4 Observe and describe that heat flows in predictable ways, moving

from warmer objects to cooler ones until they reach the same temperature.

Temperature

Measure of kinetic energy of molecules

Measured with a thermometer

3 Scales◦Fahrenheit◦Celsius◦Kelvin

F = Fahrenheit (used for weather)◦ Water boils at 212°F.◦ Water freezes at 323° F.

C = Celsius (used in science)◦ Water boils at 100°C.◦ Water freezes at 0°C.

K = Kelvin (used in science)

◦ Only scale that has absolute zero Particles are said to have no

movement at this temp.

Thermal Energy

◦The total energy of the particles in a material

◦Depends on temperature, mass, and type of substance

Which beaker of water has more thermal energy?◦B - same

temperature, more mass

200 mL

80ºCA 400 mL

80ºCB

HEAT

HEAT is the transfer of energy from one object to another when the two things are at different temperatures and in some kind of contact. ◦Always transfers from hot to cold

Ex: Teapot heats on stove top cup of tea cools down (loses energy as heat)

Heat TransferHeat is always

transferred from hot to cold.

Heat is transferred by conduction, convection, and radiation.

KNOWLEDGE CHECK

1. ____ is a measure of how quickly atoms are moving.

2. A ____ measures the temperature of matter.

3. The total amount of ____in an object is known as thermal energy.

4. Which object has more thermal energy: Cup of coffee at 80°F or a bathtub filled with coffee at 60°F?

KNOWLEDGE CHECK

1. TEMPERATURE is a measure of how quickly atoms are moving.

2. A THERMOMETER measures the temperature of matter.

3. The total amount of KINETIC ENERGY in an object is known as thermal energy.

4. Which object has more thermal energy: Cup of coffee at 80°F or a bathtub filled with coffee at 60°F?BATHTUB = more particles, more energy

TRANSFER of ENERGY

TRANSFER OF THERMAL ENERGY

Thermal energy is always moving all around you.

Thermal energy affects your life in very important ways.

Changes in weather, cooking your food, and heating your house are a few of the ways the transfer of thermal energy helps us.

The transfer of heat by direct contact between objects or particles

Heat transferred by the movement of molecules within a substance

Movement occurs from warmer areas to cooler areas

Heat transferred through space in the form of waves

EXAMPLE: The sun’s rays causing a sunburn

Helping or Slowing the Flow of Energy

CONDUCTOR INSULATORConductors are

materials that transfer heat easily.

Examples: ◦metals like copper and gold

An insulator is a material that does not transfer heat easily.

Examples: ◦ liquids and gases◦ jacket

KNOWLEDGE CHECK

1. What examples of thermal energy and thermal energy transfer can you see around you right now?

KNOWLEDGE CHECK

1. What examples of thermal energy and thermal energy transfer can you see around you right now?

Microwave, sun = radiation Stove/pan, spoon in heated pot =

conduction Air currents = convection

MATTER and HEAT

MATTER and HEAT

States of Matter Energy and Matter

SOLID = particles are close together, move slow (vibration)

LIQUID = particles spread apart, slide past each other

GAS = particles move fastest, move everywhere (spread out)

Solid = least amount of energy

Liquid = medium energy

Gas = most energyEnergy is related to

particle movement.

PHASE CHANGE and ENERGY

Phase changes occur when an objects state of matter change.

In order for a change in phase to occur, energy must be either released or absorbed.

Solid -> Liquid◦ Melting◦ Energy is absorbed.

Liquid -> Solid◦ Freezing◦ Energy is released.

Liquid -> Gas◦ Vaporization◦ Energy is absorbed.

Gas -> Liquid◦ Condensation◦ Energy is released.

Solid -> Gas◦ Sublimation◦ Energy is absorbed.

KNOWLEDGE CHECK

Identify whether energy needs to be absorbed or released in the following scenarios:

1. Ice cube melting2. Boiling water3. Dry ice placed in the air4. Dew forming on grass

KNOWLEDGE CHECK

Identify whether energy needs to be absorbed or released in

the following scenarios:1. Ice cube melting Released2. Boiling water Absorbed3. Dry Ice placed in the air Absorbed4. Dew forming on grass Released