1. Ch 10-2
What is Heat?

2. II. Conduction, Convection, Radiation
There are three ways to transfer thermal energy.
Conduction
Convection
Radiation
(Thermal) Conduction is the transfer of thermal energy from one substance to another through direct contact.
When objects touch each other, their particles collide. Thermal energy is transferred from the higher-temperature substance to the lower-temperature substance

3. Conductors and Insulators
The end of this spoon will warm up because conduction, the transfer of energy through direct contact, occurs all the way up the handle.
Conductors and Insulators
(Thermal) conductors are substances that conduct thermal energy very well.
EX: Metal spoon in boiling water
EX: Curling iron
(Thermal) insulators are substances that do not conduct thermal energy very well.
EX: Wooden spoon in boiling water
EX: Oven mitt

4. Convection
Convection is the transfer of thermal energy by the movement of a liquid or a gas (fluid).
In a fluid being heated from the bottom:
The particles at the bottom of the fluid gain energy and become less dense.
The less dense/hotter particles rise – pushing the more dense/cooler particles out of the way.
The cooler particles sink. As they reach the bottom, they are heated. Meanwhile, the hotter particles that rose to the top cool down, and the cycle repeats itself.
This creates a circular motion known as a convection current.

5. Radiation and Greenhouse Effect (SKIP)
Radiation is the transfer of energy by electromagnetic waves, such as visible light and infrared waves.
Radiation differs from conduction and convection because it does not require matter in order to transfer energy. Radiation can travel through empty space.
Radiation and Greenhouse Effect (SKIP)

6. Heat and Temperature Change Thermal Conductivity (SKIP) Specific Heat
Specific heat is the amount of energy needed to change the temperature of 1kg of a substance 1°C.
AKA: the amount of energy it takes to make an object hotter or colder
Sand at the beach has a lower specific heat than the water. Less energy is needed to warm the sand.
Conductors usually have low specific heat while insulators usually have high specific heat.