….What’s the difference?? Temperature, Thermal Energy, and Heat

Which has more thermal energy?

The Iceberg has more thermal energy

How??? Lets look at some definitions. Temperature is defined as the average kinetic energy of the particles of matter. Thermal energy is the total kinetic energy of moving particles of matter. …..so how is there really a difference???

Temperature When particles of matter move more quickly, they have more kinetic energy, so their temperature is higher. With a higher temperature, matter feels warmer. When particles move more slowly, they have less kinetic energy on average, so their temperature is lower. With a lower temperature, matter feels cooler. To measure this we use a thermometer. Many thermometers measure temperature with a liquid that expands when it gets warmer and contracts when it gets cooler.

Thermal Energy Anything that is moving has kinetic energy, and the faster it is moving, the more kinetic energy it has. The total kinetic energy of moving particles of matter is called thermal energy. It’s not just hot things have thermal energy. All matter has thermal energy, even matter that feels cold. That’s because the particles of all matter are in constant motion and have kinetic energy. Thermal energy takes into account the mass (how much stuff is inside the object)

Temperature and Thermal Energy Temperature is the average kinetic energy of particles of matter, whereas thermal energy is the total kinetic energy of particles of matter. Lets look at an example that may be easier to visualize the differences:

Day 2 Temperature, Thermal Energy, and Heat

Temperature and Thermal Review What is temperature? What is thermal energy? Does all matter have thermal energy? How? Lets look at an example that may be easier to visualize the differences:

Fire and Ice

Pennies and Quarters Lets imagine this, we have some quarters. How much are they worth? Now lets say that quarter represents an atoms in the fire and its value is its “temperature”. Now, we also have some pennies. How much are they worth? Again lets say each penny represents an atom in the iceberg and its value is its “temperature”.

Temperature and Thermal Energy So if I have a stack of quarters, the average value or “temperature” of those coins would be 25. So each particle has a value of 25. And it I have pile of pennies, the average value of “temperature” of those coins would be 1. So each particle has a value of 1. Now lets look at thermal energy.

Which one is worth more overall???

Temperature and Thermal Energy Even though the quarters have a higher “temperature” (25), because there are fewer of them the stack of quarters has less “thermal” energy than the pennies. So even things with a “low temperature” still have energy and if they have enough mass it can have a higher amount of thermal energy. (Iceberg and fire)

Which has more thermal energy? The Iceberg has more thermal energy

Which has the highest temperature? The fire has a higher temperature

What about heat??? Heat is the transfer of thermal energy between substances. As particles are given energy (heated) their atoms move faster and faster. They begin to bump into the atoms beside them and transfer energy to those atoms which causes them to move faster.

Heat Thermal energy always moves from matter with greater thermal energy to matter with less thermal energy, so it moves from warmer to cooler substances. Faster-moving particles of the warmer substance bump into and transfer some of their energy to slower-moving particles of the cooler substance. Thermal energy is transferred in this way until both substances have the same thermal energy and temperature.

Heat and Ice Tea. Which has more energy, tea or the ice in it? As the ice sits in the tea (which has more energy). The particles in the tea will begin bumping into the ice particles. As they do energy is transferred from the tea to the ice. The tea begins to slow down and the ice particles begin to speed up. This continues until all the particles are at the same temperature (when the ice has melted).

Scenario Imagine we have a tea cup (about 8 ounces) filled with boiling water (100 Degrees Celsius). Right next to it we have a Big Q from QT (32 ounces) filled with water that is 50 Degrees Celsius. Which one has the highest temperature? Which one has the highest thermal energy? Now imagine we throw ice cubes into the cup, what does heat do?

Temp, Thermal, and Heat Assignment Read Section 2.3 again, and answer questions 1-4 on page 57 and 60.