Thermal Energy of Water

Thermal Energy and Water

Thermal energy added to a system
increases the kinetic energy of the
molecules and results in temperature
and phase changes.

Learning Targets:

I can compare the effects of adding or

subtracting thermal energy to the states of
water.

I can relate the three states of water to

the water cycle.

I can analyze and explain the difference in

average winter temperatures among areas in
central and western Virginia and areas along
the Chesapeake Bay and Atlantic coast.

Multiple Choice

What does thermal mean?

• freezing

• melting

• heat

• condensation

Thermal Energy and Water

Thermal energy can change the
phase(state)of water.

• Adding thermal energy gives the

molecules more kinetic energy which
causes water molecules to spread out.

• Taking away thermal energy causes

molecules to have less kinetic energy.

• Solids have the least kinetic energy and

gases have the most kinetic energy.

Multiple Choice

When water turns from water vapor to ice, thermal (heat) energy -

• increases

• decreases

Multiple Choice

When water turns from ice to liquid water, thermal (heat) energy -

• increases

• decreases

Multiple Choice

When water turns from liquid water to water vapor, thermal (heat) energy -

• increases

• decreases

Water Cycle and Energy

Image source https://www.youtube.com/watch?v=ct7WE8wJURQ

The water cycle is powered by
thermal energy from the sun.

Water is found in all three states of
matter as it goes through the water
cycle

Where is water found as a solid in the water
cycle? Describe the thermal energy change
to change water to a solid.

Where is water found in the liquid state in
the water cycle? Describe the kinetic and
thermal energy when water is a liquid.

Where is water found as a gas in the water
cycle? Describe the kinetic and thermal
energy changes as water becomes a gas.

What is the source of the thermal energy that
causes the phase changes in the water cycle?

Multiple Choice

What powers the water cycle?

• wind

• evaporation

• precipitation

• sun

Open Ended

Where is water found as a solid in the water cycle?

Open Ended

Where is water found as a liquid in the water cycle?

Open Ended

Where is water found as a gas (water vapor) in the water cycle?

Freezing

Thermal energy decreases
Kinetic energy decreases

• Liquid to Solid
• Snow and ice form

Melting

Thermal energy increases
Kinetic energy increases
• Solid to Liquid
• Ice and snow return to

liquid form

Condensation

Thermal energy decreases
Kinetic energy decreases
• Gas to Liquid
• Clouds form

Evaporation

Thermal energy increases
Kinetic energy increases

• Liquid to Gas
• Earth’s surface waters

evaporate due to heat
from the sun

Multiple Choice

When thermal (heat) energy increases, kinetic energy _________

• increases

• decreases

Multiple Choice

When thermal (heat) energy decreases, kinetic energy _________

• increases

• decreases

Waters Absorbs and Releases Heat Energy Slowly

Water absorbs and releases thermal energy
without showing large changes in temperature.
Water absorbs and releases heat slower than the
air and land.
Large bodies of water (oceans and lakes) absorb
heat energy in the summer and release it slowly in
the winter

examples:
• A lake will feel cooler than the air above it on a

hot day

• The climate near large bodies of water is milder

than in areas without large bodies of water

The water
is cooler
than the

air!

Multiple Choice

Large bodies of water absorb (take in) heat in the summer and release heat in the winter.

• True

• False

Moderate Climates are Found Near Large Bodies of Water

Large bodies of water act to moderate the climate of surrounding areas by
absorbing thermal energy in summer and slowly releasing that energy in the winter.

This is the reason, the climate near large bodies of water is milder than areas
further from large bodies of water.

Coastal regions do not have as extreme temperature ranges during summer and
winter as inland regions

Multiple Choice

Large bodies of water absorb (take it) heat in the -

• summer

• winter

• spring

• fall

Multiple Choice

Large bodies of water slowly releases (lets go) heat in the-

• summer

• winter

• spring

• fall

Open Ended

Why do areas near water have more moderate temperatures than those inland?

Review

Thermal energy added to
a system increases the
kinetic energy of the
molecules and results in
temperature and state
(phase) changes.

Thermal energy can
change the state
(phase) of water.
Adding thermal energy
causes water molecules
to spread out. The
molecules have more
kinetic energy. Taking
away thermal energy
causes molecules to
have less kinetic energy.

The water cycle is
powered by thermal
energy from the sun.
Water is found in all
three states (phases)
of matter as it goes
through the water
cycle.

Water can absorb and
release thermal energy
without showing large
changes in
temperature. Water
absorbs and releases
heat slower than the air
and land.

Large bodies of water
act to moderate the
climate of surrounding
areas by absorbing
thermal energy in
summer and slowly
releasing that energy in
the winter.

Open Ended

Interesting fact or question