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WHAT IS HEAT: TRANSFER OF THERMAL ENERGY?

Heat is the transfer of thermal energy from one object to another. The transfer of thermal energy can occur by conduction, convection, or radiation. Some materials can store more energy than others.

To better understand Heat: Transfer of Thermal Energy…

WHAT IS HEAT: TRANSFER OF THERMAL ENERGY?. Heat is the transfer of thermal energy from one object to another. The transfer of thermal energy can occur by conduction, convection, or radiation. Some materials can store more energy than others. To better understand Heat: Transfer of Thermal Energy…

## LET’S BREAK IT DOWN!

### Heat, thermal energy, and temperature

We all have a feel for what temperature is, and we even have a shared language to qualitatively describe temperature. The water in the shower feels warm. It’s cold outside. Don’t touch that, it’s hot! But defining temperature scientifically is not so easy. Basically, temperature is what the thermometer reads. To understand what that means, we have to think about substances at the macroscopic level (we can see it with our eyes) and at the particle level (atoms and molecules that make up the substance, which are too small to be seen with just our eyes).

Hot coffee in a cup may appear to be motionless, but the particles that are contained within it have kinetic energy. At the particle level, the atoms and molecules that make up the coffee are vibrating, rotating, and moving through the space of the cup. Stick a thermometer in the cup of coffee, and you will see evidence that the water possesses kinetic energy. The water’s temperature, as reflected by the thermometer’s reading, is a measure of the average amount of kinetic energy of the coffee molecules.

You know from experience that if you leave the hot cup of coffee sitting on the countertop over time it will cool down. On the macroscopic level, the coffee and the cup are transferring heat to their surroundings (i.e., the air and the countertop). The fact that the coffee’s temperature decreases over time is evidence that the average kinetic energy of its particles is decreasing. We refer to this transfer of energy from the coffee and the cup to the surrounding air and countertop as heat. Heat is the transfer of energy from hotter objects or regions to colder objects or regions.