Acc intro to thermal energy spring 2012

Agenda Bell Work

• Notes: Intro to Thermal Energy

• Temperature Research and Calculations

• HW: Chp 9 pg 136-143

• Review Q’s 1-20

In the chart below fill in one difference and one similarity that you came up with:

Similarity Difference

Hot Cup of Coffee

Cold Cup of Coffee

Intro to Thermal EnergyIntro to Thermal Energy

February 19, 2013February 19, 2013

ObjectivesObjectives1.1. Explain the motion of molecules in Explain the motion of molecules in

the different states of matterthe different states of matter

2.2. Understand the definition of Understand the definition of thermal energy and what happens thermal energy and what happens in thermal equilibriumin thermal equilibrium

Movement of atomsMovement of atoms• All matter is constantly movingAll matter is constantly moving

• Moving particles determines whether Moving particles determines whether an object is solid, liquid, or gasan object is solid, liquid, or gas

Kinetic EnergyKinetic Energy

• The warmer an object is the more The warmer an object is the more kinetic energy it haskinetic energy it has= more thermal energy= more thermal energy

Thermal EnergyThermal Energy• The total energy of all it’s atoms and The total energy of all it’s atoms and

moleculesmolecules

Hot or ColdHot or Cold• TemperatureTemperature

• Thermometer measures temperature Thermometer measures temperature by expansion or contraction of a by expansion or contraction of a liquidliquid

Eureka 20Eureka 20

TemperatureTemperature• Related to the random Related to the random

motion of atoms and motion of atoms and moleculesmolecules

• average kinetic energy of average kinetic energy of moleculesmolecules

• Thermometers read their own Thermometers read their own temperaturetemperature

• Energy flows between the Energy flows between the thermometer and the object until thermometer and the object until they reach an equal temperaturethey reach an equal temperature

• This equilibrium is called a Thermal This equilibrium is called a Thermal equilibriumequilibrium

Flow of Thermal EnergyFlow of Thermal Energy

•From a warmer substance to a From a warmer substance to a colder onecolder one

•HEAT – thermal energy in motionHEAT – thermal energy in motion

Upper Limit of Temperature

Solid Liquid Gas

What happens after the Gas state?

Plasma – Cloud of electrically charged particles- stars, millions of degrees C

What’s cold?What’s cold?

•The absence of thermal energyThe absence of thermal energy

•An object is cold because of the An object is cold because of the loss in thermal energyloss in thermal energy

•Eureka 21Eureka 21

HeatHeat

•Measured in JoulesMeasured in Joules

•4.2 Joules = heat to change 1 4.2 Joules = heat to change 1 gram of water 1 Celsius degreegram of water 1 Celsius degree

ccaloriealorie•Unit of heat used in the United StatesUnit of heat used in the United States

•Amount of heat needed to change 1 Amount of heat needed to change 1 gram of water 1 Celsius degreegram of water 1 Celsius degree

•c = Mass (Change in temp)c = Mass (Change in temp)

•1 1 ccalorie = 4.2 joulesalorie = 4.2 joules

•Energy ratings of food and fuels Energy ratings of food and fuels are measured by the energy are measured by the energy released when they are burnedreleased when they are burned

•KiloKilocalories = calories = CCalories we know alories we know on food packages (capitol C)on food packages (capitol C)

•To the Weight Watcher, the To the Weight Watcher, the peanut contains 10 peanut contains 10 CCaloriesalories

•To the physicist, it releases To the physicist, it releases 10,000 10,000 ccalories of energy when alories of energy when burned or digestedburned or digested