13.1 TEMPERATURE I can… -identify increases/ decreases in temperature as a function of the difference in thermal energy lost or absorbed.

THERMAL ENERGY: THE KINETIC ENERGY OF A SUBSTANCE’S ATOMS

TEMPERATURE AND ENERGY  Temperature: a measure of how hot (or cold) something is; specifically, a measure of the average kinetic energy of the particles in an object.  Is it possible to find the kinetic energy of every particle in an object and calculate its average?  How is temperature calculation?  Thermometer: uses Mercury or colored alcohol to expand as temperature increases, which allows particles of the liquid to move up the little tube.

FAHRENHEIT VS. CELSIUS

THE KELVIN SCALE IS BASED ON ABSOLUTE ZERO  Absolute zero: the temperature at which molecular energy is at a minimum (0K on the Kelvin scale or o C  T k = t c +273

MATH PRACTICE  The highest atmospheric temperature ever recorded on Earth was 57.8 o C. Express this temperature bath in degrees Fahrenheit and in kelvins.  T f = (1.8 x 57.8) = = 136 o F  T k = =331K

QUICK LAB: HOW DO TEMPERATURE AND ENERGY RELATE?  Analysis  Which cup had the higher final temperature?  Both cups had the same starting temperature. Both sets of washers started at 100 o C. Why did one cup reach a higher final temperature?  The cup with 30 washers reaches a higher final temperature because a greater mass (of 30 washers opposed to 10 washers) can transfer more energy.

TEMPERATURE CHANGES INDICATE AN ENERGY TRANSFER  Heat: the energy transferred between objects that are at different temperatures  What happens to glass of ice water if you hold it in your hands for a long period of time?  Do M&M candies really melt in your mouth and not your hand?

13.2 ENERGY TRANSFER I can… -recognize that conductors have a high rate of energy transfers and insulators have a low rate. -identify the factors that affect rate at which thermal energy is transferred.

METHODS OF ENERGY TRANSFER  Thermal conduction: the transfer of energy as heat through a material  Convection: the movement of matter due to differences in density that are caused by temperature variations  Convection current: the vertical movement of air currents due to temperature variations.  Radiation: the energy that is transferred as electromagnetic waves, such as visible light and infrared waves.

CONDUCTORS AND INSULATORS  Any material through which energy can be easily transferred as heat is called a conductor.  Examples?  conduction.html conduction.html  Insulators prevent energy transfer.  Exampels?  Winter coats, house/attic insulation. particle collision.  ***Remember energy is transferred through particle collision.

SPECIFIC HEAT  Specific Heat: the quantity of heat required to raise a unit of mass of homogeneous material 1 K or 1 o C in a specified way given constant pressure and volume.  Energy=(specific heat (c)) x (mass) x (temperature change)  Practice: how much energy must be transferred as heat to the 420 kg of water in the bathtub in order to raise the water’s temperature from 25 o C to 37 o C? Substancec(J/kg x K)Substancec(J/kg x K) Water (liquid4186Copper385 Steam1870Gold129 Ammonia (gas)2060Iron449 Ethanol (liquid)2440Mercury140 Aluminum897Lead129 Carbon (graphite) 709Silver234