Download Thermal Energy Notes - Burnet Middle School

Thermal Energy
Often people mistakenly use thermal energy, temperature, and heat as interchangeable
terms, however each has a very unique and specific scientific meaning.
Matter is made up of particles or molecules. These molecules move (or vibrate)
constantly. This is because the particles have kinetic energy, or energy due to motion.
The particles also have potential energy (stored energy). Potential energy of the
particles depends on their interactions, such as their arrangement and the attractive
forces among the particles.
Thermal energy is the total energy of all the particles in an object. In other words,
thermal energy is the sum of the kinetic and potential energy in the particles of a
substance. The thermal energy of an object depends on the number of particles in the
object, the temperature of the object, and the arrangement of the object’s particles.
Temperature is the measure of the average kinetic energy of the particles in a sample
of matter. When the particles in a material speed up, the temperature increases, when the
particles in a material slow down, the temperature decreases.
The temperature of an object is measured in degrees Celsius (°C). Temperature can
also be measured in a Fahrenheit scale. It is denoted by the symbol 'F'. When using the
Fahrenheit scale, water freezes at 32 °F, and boils at 212 °F. When using the Celsius
scale, water freezes at 0°C and boil at 100°C.
Let's look at this example to see how thermal
energy and temperature are related:
A swimming pool at 40°C is at a lower
temperature than a cup of tea at 90°C. However,
the swimming pool contains a lot more water.
Therefore, the pool has more thermal energy than
the cup of tea even though the tea is hotter than
the water in the pool.
Heat is the movement of thermal energy from a
warmer object to a cooler object. For example, a
cup of hot tea has thermal energy. When you put
an ice cube into your hot tea, some of this energy is transferred from the hot tea to the
particles in the ice cube. What happens next? The cup of tea is cooler because it lost
thermal energy to the ice. The ice will also begin to melt as it gains thermal energy from
the particles of the tea.
Check for understanding:
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What is kinetic energy?
Why do the particles of solids, liquids and gases have kinetic energy?
What is potential energy?
What does potential energy depend on?
What is thermal energy?
What is temperature?
What is the difference between thermal energy and temperature?
Which will have more thermal energy: a lake with a temperature of 75 °F, or a
glass of water with a temperature of 90 °F? Explain
9. What is heat?
10. Explain the heat transfer that occurs when you hold a cup of hot chocolate.
11. Explain the heat transfer that occurs when you hold a glass of ice water.