Thermal Energy, Heat, and Temperature

Kinetic Theory of Matter All matter is made of particles (atoms and molecules) and these particles are always moving.

All matter has thermal energy. Thermal Energy (Q) All matter has thermal energy. Internal kinetic energy of material (motion of particles). depends on number of particle (mass) speed of the particles (temperature). the type of particles (specific heat “C”) Q = m x T x C

Temperature Measures how fast particles are moving. High temperature. Molecules move faster. Molecules get further apart (expands). Becomes less dense. Low temperature. Molecules move slower. Molecules get closer together (contracts). Becomes more dense.

Heat Is the transfer or movement of thermal energy from one object to another. Energy moves from warmer to cold 3 ways!!

1. Conduction The transfer of thermal energy through matter by the direct contact of particles. Objects are touching. Occurs when molecules collide with one another transferring their energy.

Conduction When you heat a metal strip at one end, the heat travels to the other end. As you heat the metal, the particles vibrate, these vibrations make the adjacent particles vibrate, and so on and so on, the vibrations are passed along the metal and so is the heat. We call this? Conduction

2. Convection Is the transfer of energy through the movement of a fluid (liquid or gas). Creates convection currents: circular motion of a gas or liquid as warm fluids rise and cool fluids sink. Ex. Wind.

Water movement Cools at the surface Convection current Hot water rises Cooler water sinks

Why is it windy at the seaside?

3. Radiation Is the transfer of energy in the forms of waves. Waves are absorbed or reflected Those absorbed turn to heat Matter is not necessary to transfer energy this way. Example: sunlight, microwave oven.

Insulation Something that prevents heat transfer. Could be a barrier to slow convection. Could be reflective to slow radiation. Could be a gas to slow conduction. Insulation is something that is a poor conductor of heat. Examples: air, wood, plastic, fiberglass.