Italicized font represents information to be shared orally or physically completed with the students at this time.

The non-italicized font represents additional information included to support the teacher’s understanding of the content being introduced within the CELL.

ASK WHY

Heat, thermal energy, and temperature greatly influence the way we live. We monitor our body temperature, dress for the hot and cold, build homes, schools, and cars with heating and cooling systems, and passionately search for alternative fuels as the threat of global warming takes hold. To live safely and productively, it is important to understand the thermal behaviors that govern our bodies and the world. 

BRANCH OUT

Remind students that energy engineers review architectural plans and make changes to the design to improve the heating and cooling properties of a new home. They also use infrared cameras during an energy audit to determine where heat losses are the greatest in a room.

GET FOCUSED

This Investigation is designed to help you to answer the following Focus Questions:

• What is the relationship between heat, kinetic energy, and temperature? Heat is the transfer of thermal energy, which includes both kinetic and potential energy.

• What changes in matter accompany changes in heat? In general, matter expands when heated and contracts when cooled because of changes in the kinetic energy of molecules.

Note: These questions are located in students’ SDRs at the beginning and end of the Investigation.

Note: These are succinct responses to the Focus Questions and are placed here for your reference at this time. Fully developed responses to the Focus Questions can be found on the PostLab page.

GO DEEPER

As a class, read the Background(s) in the Investigation. Have students read the information aloud or silently to themselves. When students have finished, discuss the following concepts as a class:

• Solids, liquids, and gases are composed of molecules that are vibrating.
• Vibrating molecules have kinetic energy, the amount of which can change.
• Molecules have bonds (or forces) that attract them to each other.
• The bonds between molecules in a solid are strong.
• The bonds between molecules in a liquid are moderate.
• The bonds between molecules in a gas are weak.
• The bonds require energy to form and break, which means that the molecules have potential energy stored in their bonds.
• Heat or thermal energy is the term used to describe the total of all energy within a substance (both kinetic and potential).
• Temperature is a measure of the average kinetic energy of molecules.
• Something with a higher temperature (hotter) has more kinetic energy than something with a lower temperature (colder).
• The Law of Conservation of Energy states that energy can neither be created nor destroyed, it can only change form.
• When substances that have different kinetic energies come in contact with one another, kinetic energy is transferred from areas of high kinetic energy to areas of lower kinetic energy.
• No energy is lost when energy is transferred between substances; what one substance loses, the other gains.
• Changes in the kinetic energy of molecules can produce physical changes in matter.
• Changes between different states of matter are referred to as phase changes.
• As a solid gains kinetic energy, the bonds between molecules weaken, and the solid turns to a liquid (melting).
• The molecules within a liquid take up more volume than molecules within solids.
• As a liquid loses kinetic energy, the bonds between molecules strengthen, and the liquid turns into a solid (freezing).
• As a liquid gains kinetic energy, the bonds between molecules weaken, and the liquid turns to a gas (vaporization).
• The molecules within gases take up more volume than molecules within liquids.
• As a gas loses kinetic energy, the bonds between molecules strengthen, and the gas becomes a liquid (condensation).

Note: These concepts are integrated into the Background(s) and are used to deepen students’ comprehension of big ideas.

LEARN THE LabLearner LINGO

The following list includes Key Terms that are introduced in the Investigation Background(s). They should be used, as appropriate, by teachers and students during everyday classroom discourse.

• kinetic energy
• temperature
• heat
• equilibrium
• Law of Conservation of Energy
• heat transfer
• freezing point
• boiling point

Note: Definitions to these terms can be found on the Introduction page to the CELL.

Note: Additional words may be bolded within the Background(s). These words are not Key Terms and are strictly emphasized for exposure at this time.

SET FOR SUCCESS

• Assess the background knowledge of the students by asking them to complete the prediction questions in their SDRs.

Note: Students will be able to formulate answers to these questions after they have completed the Investigation.

• Discuss the concepts of heat, temperature, and kinetic energy and how they are related.
• Play the video below. Stop to ask students questions or answer students’ questions when necessary. Remind students to follow along with their SDRs and make any notes that they think might be helpful.
• After the video, direct students to divide into their lab groups to discuss their strategy for the lab. For example, they may assign certain group members to perform specific functions during the lab.

Note: The purpose of the video is to allow students to anticipate the laboratory experience they will soon encounter. Students should leave this PreLab session with a firm idea of what to expect and how to perform in the lab.

Note: Homework is posted below the video.

HOMEWORK

Tell students that they should review the Investigation in preparation for the Lab.