Where Does Thermal Energy Hide? Heat in Everyday Life

What You'll Learn

• Thermal energy always moves from something hotter to something cooler, never the other way — "cold" isn't a thing that jumps IN, it's heat leaving.
• Metal is a speedy energy-mover (conductor); wood, plastic, and cloth are slowpokes (insulators) — same amount of heat, wildly different speed getting there.
• Two objects at the exact same room temperature can FEEL different — the fast-mover (metal) yanks thermal energy out of your hand quicker, which your skin reads as "cold."

Words to Know

Thermal energy

The energy of how fast the tiny particles inside something are jiggling around — more jiggle means more heat.

A steaming mug of cocoa has particles jiggling super fast; a glass of ice water has particles jiggling slowly.

Conductor

A material that moves thermal energy along really FAST.

A metal spoon is a conductor — it gets hot almost as fast as the soup it's sitting in.

Insulator

A material that moves thermal energy along really SLOWLY.

A wooden spoon is an insulator — it stays cool even sitting in hot cocoa.

Check What You Learned

Fun Facts

• A metal spoon left standing in a mug of hot liquid can become nearly too hot to hold bare-handed within about a minute, while a wooden or plastic spoon in the same mug stays comfortably cool, because metals conduct thermal energy far faster than wood or plastic

  Source: U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy

• A metal object and a wooden object sitting in the same room are actually the exact same temperature, but the metal one feels colder to the touch because it pulls thermal energy out of your skin much faster than wood does

  Source: standard thermal conductivity principles, U.S. Department of Energy

• Thermal energy is the total kinetic energy of the jiggling, vibrating particles that make up matter, and the faster the particles move, the higher the thermal energy

  Source: NASA Science education materials

• Thermal energy always flows from a warmer object to a cooler one until they reach the same temperature, and never spontaneously flows the other way

  Source: standard physical science curricula

• The human body constantly produces thermal energy and normally stays near 98.6°F (37°C), which is itself a source of heat you can feel radiating off a friend's arm or a sleeping pet

  Source: National Library of Medicine, normal human body temperature references

• Rubbing your hands together converts the energy of motion into thermal energy, which is why they warm up

  Source: standard physical science curricula