What is Thermal Energy (Heat)?
Thermal Energy (Heat) is a form of energy that can cause change in other substances by exciting particles or changing the density of the material.
How can Thermal Energy be transferred?
It can be transferred via conduction, convection, and radiation; however, it does not transform into a new material.
What does Density refer to?
Density refers to how compacted the space between the particles is.
What are the characteristics of a Solid?
Particles are tightly packed (high density), have strong bonds, can vibrate slowly, and the material is able to hold its shape.
What are the characteristics of a Liquid?
Particles are loosely packed (moderate density), have loose bonds, can move over each other and flow, and the material cannot hold its shape.
What are the characteristics of a Gas?
Particles are not packed (low density), have large amounts of space between them, have a lot of energy, resulting in particles that unbound and travel in straight lines until they collide with each other, and the material cannot hold its shape and particles will spread out.
What happens when heat is added to particles?
Heat adds kinetic energy to particles, increasing their temperature, causing them to gain kinetic energy and move faster, spreading out and becoming less dense.
What happens when temperature rises enough?
If the temperature has risen enough, bonds may break between particles causing a change in state (melts or evaporates).
What happens when heat is lost?
The particles lose their kinetic energy causing them to slow down and become more dense (contract).
What is Temperature a measure of?
Temperature is a measure of the average kinetic energy in a particle.
What is Thermal Energy/Heat a measure of?
Thermal energy/Heat is a measure of the total energy of all particles within an object.
Do thermometers measure thermal energy?
Thermometers measure temperature but do not measure thermal energy.
How does Thermal Energy Transfer occur?
Thermal energy flows from areas of a higher temperature to areas of a lower temperature. The greater the energy difference, the faster the flow of heat.
What are the three methods of heat transfer?
The process of heat transfer can happen in three ways: conduction, convection, and radiation.
What is Conduction?
Conduction is the method of thermal energy transferring by direct contact (typically within and between solids) in which energy is passed by exciting (vibrating) particles.
E.g. Touching an ice block in your hands, standing on cold ceramic tiles & touching a hot iron.
What is Convection?
Convection is the method of thermal energy transferring by circular convection currents (typically within liquids and gases) due to differences in density.
Process: The warm gas/liquid is less dense than cool gas/liquid and therefore moves upwards, while the cool gas/liquid is more dense than warm gas/liquid and therefore moves downwards.
What is Radiation?
Radiation is the transfer of thermal energy in the form of electromagnetic waves (Infrared waves) through space.
Infrared (heat) waves travel at the speed of light and do not require particles to transfer.
What are Conductors?
Conductors are substances/materials that transfer thermal energy through conduction easily and quickly.
E.g. metals.
What are Insulators?
Insulators are substances/materials that transfer thermal energy through conduction with difficulty slowly (poor heat conductors).
E.g. Clothes, wood, rubber.
What is the law of energy?
The law of energy states that it cannot be created nor destroyed but it can be transferred or transformed.
