Unit 2 Thermal Energy
I am learning about heat transfer in matter.
I can identify differences between conduction, convection, and radiation.
I can investigate and describe how different materials respond to heat.
I am learning about the design process.
I can apply the design process to demonstrate heat transfer.
I can model and create various methods of heat transfer and describe what happens to energy during transformations.
How Thermal Energy Moves
Thermal energy is energy in the form of heat. When you add thermal energy to matter, the kinetic energy of its particles increases, raising its temperature (which you can measure with a thermometer).
Heat moves through three types of energy transfer: conduction, convection, and radiation. Conduction occurs when a hot object touches a cooler one—thermal conductors like metal allow heat to flow easily, while thermal insulators like wood resist heat flow. Convection transfers heat through the movement of fluids (liquids or gases) in a current—hot material rises while cool material sinks. Radiation transfers energy through space as electromagnetic waves, like infrared light from the sun (solar energy) or visible light we can see.
Materials respond differently to heat based on their properties. A conductor allows heat to pass through easily, while an insulator does not. Some materials have high reflectivity and reflect heat away, while others use absorption to take in and retain thermal energy.
Understanding these processes helps us design solutions using specific criteria and constraints—like choosing the right materials to keep a home warm or a cooler cold!
Example 1
Example 2
Example 3
Changes of state
The energy of the moving particles can overcome the forces that hold particles together. This results in a change of state:
• Melting
• Boiling
• Solidifying
Heating and cooling
The graph below demonstrates the relationship between thermal energy, phase (state) changes, and particle arrangement as a substance is heated or cooled.
