Warm Up 3 examples of physical changes are: 3 examples of chemical changes are:

Temperature Temperature is a measure of the average kinetic energy of particles of a substance. At higher temperatures, particles move faster At lower temperatures, particles move slower Cooler Warmer

The gas particles on the right have a higher average kinetic energy than those on the left. So, the gas on the right is at a higher temperature.

Four scales: 0 K = 0 R: absolute zero Fahrenheit (°F) Celsius (°C) Kelvin (°K) Rankine (°R) 0 K = 0 R: absolute zero All motion stops

Thermal Energy Thermal energy is the total amount of kinetic energy in a substance. Measured in Joules thermal energy and temperature are NOT the same thing.

Thermal Energy

Heat - the movement of thermal energy Measured in Joules ALWAYS moves from higher to lower temperatures Will move until objects reach thermal equilibrium (equal temps) 34o C 67o C

1. On a cold day, you make some hot chocolate 1. On a cold day, you make some hot chocolate. Which way will the thermal energy move? From the hot chocolate to the environment From the environment to the hot chocolate

2. On a hot day, you pour a glass of ice water. Which way will the thermal energy move? From the ice water to the environment From the environment to the ice water

Average kinetic energy of particles Total kinetic energy of particles Energy measured Units measured Temperature Thermal Energy Heat Average kinetic energy of particles Degrees (C, F) or K Total kinetic energy of particles Joules Transferred energy Joules

Thermal Expansion What is thermal expansion? Thermal expansion - as an object is heated, that object expands. Exception to rule: water

Thermal Expansion As the temperature of roads increase or decrease, their volume expands or contracts. Expansion joints like this are placed in bridges to account for their frequent change in volume. As the temperature in a liquid thermometer increases, its volume also increases, causing the level of the liquid to rise. As hot air expands, it becomes less dense, allowing the hot air balloon to rise.