Study Notes for Chapter 10

·  Temperature is the measure of how hot or cold something is. Hot and cold are not science words though….. More specifically, temperature is the measure of the average kinetic energy of a substance.

·  We use a thermometer to measure temperature. There are three types of temperature scales: Fahrenheit, Celsius, and Kelvin. In the Fahrenheit scale ….water freezes at 32 degrees and boils at 212 degrees. Celsius was based on freezing and boiling of water. In Celsius water freezes at 0 degrees and boils at 100 degrees. Kelvin was built on absolute zero. Absolute zero is where all molecular motion stops - - so 0 Kelvin is where all motion stops, water freezes at 273 Kelvin and boils at 373 Kelvin.

·  Thermal expansion is the increase in size of a substance with an increase in temperature. Most substances expand with an increase in temperature/thermal energy.

·  Expansion joints (gaps in bridges and concrete etc.) are needed to allow substances to expand without breaking.

·  Heat is the transfer of energy between substances that are at different temperatures. Heat always flows from objects with higher temperatures to those with lower temperatures.

·  Conduction is the transfer of energy from one substance to another through direct contact.

·  Convection is the transfer of energy by the movement of a liquid or a gas.

·  Radiation is the transfer of energy by electromagnetic waves. Example is visible light and infrared waves. Radiation, different than Convection and Conduction, can go through empty space.

·  Thermal conductors conduct (transfer thermal energy well) example: metals are good conductors.

·  Thermal insulators do not conduct thermal energy very well. Examples are wood and cloth.

·  In a solid there is not enough thermal energy so the particles do not move fast enough to overcome the attraction between the particles so they just vibrate in place but do not move.

·  In a liquid they move fast enough to overcome most of the attraction but not all so they slide past each other.

·  In a gas there is enough thermal energy that they move fast enough for the particles to break away from each other and move independently.