Heat and Temperature Chapter 13
Temperature Section 13.1
Temperature Measure the KE of the particles in an object Moving fast- = a hot temperature Moving slow- = a cool temperature Increase the KE will increase the temp and vice versa
Temperature Thermometer- instrument that measures and indicates temp Work using expansion Mercury rises b/c it expands with increasing heat Mercury falls b/c it contracts with decreasing temp
Temperature Fahrenheit Scale- USA is 1 of the only country that uses this scale (water freezes at 32˚) Celsius Scale- Most other countries use (water freezes at 0˚) Kelvin Scale- used in science
Kelvin Scale Absolute Zero- is -273.16˚C or 0 Kelvin Lowest possible temperature No negative numbers in Kelvin scale Converting from Celsius to Kelvin Kelvin (T)= C˚ + 273
Temp and Energy Transfer The energy transferred between objects that are of different temperatures is called Heat Goes from a higher temp to a lower temp EX Melting an ice cube in your hand Temperature is an indicator of internal KE Internal KE is transferred from a warmer object to a cooler object
Solve the Following 20ºC = ____________K -201ºC = _____________K How many ºC is 501K? How many Kelvin is 11ºC? 93.5ºC = _______________K 471.779K = ______________ºC 27 K + 190 K = ______________ºC
Solve the Following 3ºC + 110 K = ______________K 151K - 160ºC = _____________K 27K + (-10ºC) + 5K = ____________K A student puts a thermometer in boiling water. The temp is 99ºC. Convert this to kelvin.
Energy Transfer Section 13.2
Transfer of Energy Happens in 3 ways Convection Conduction Radiation
Transfer of Energy Thermal Conduction The transfer of energy as heat through a material by particle collisions
Transfer of Energy Convection Movement of matter due to differences in density that are caused by temperature variations Warm air is less dense so it rises up Air cools and sinks Convection current- vertical air movement b/c of temp diffs Cool air sinks Hot air rises
Transfer of Energy Radiation Energy that is transferred as electromagnetic waves, such as visible light and infrared waves; does not involve the movement of matter Does not require physical contact A hot object radiates more heat than a cool object Only method of energy transfer that can happen in space
Conductors and Insulators Conductor- any material that energy can be easily transferred as heat Examples: metal Insulator- a poor conductor of heat Examples: plastic, wood, rubber
Energy and Collisions Gases are poor conductors b/c particles are far apart Liquids conduct better than gases but not efficiently Solids can be either conductors or insulators Ex: cooking on a stove
Specific Heat Specific heat is the quantity of heat required to raise a unit mass of homogenous material 1 K or 1˚C in a certain way at a constant pressure and volume
Specific Heat Physical property Measured in (J/kg·K) In this book specific energy does not change
Equation energy=(specific heat) x (mass) x (temp change) Energy=cm∆T Temp change is T1-T2