Heat and Heat Technology Chapter 10

What is Temperature?  __________- A measure of the average kinetic energy of the particles in an object.  All particles are in _______________ (even if they don’t appear to be)  The faster the particles are moving, the more ____________ they have.  The more kinetic energy they have, the ________ the temperature.  Temperature measures the _______ kinetic energy of the object because individual particles are moving at different _______ and have different kinetic energies.

Measuring Temperature  Using a thermometer-  As a substance’s temperature ____________, it’s particles move faster and ____________. There is more space between them, and the substance expands.  Temperature is measured in three ways:  Fahrenheit –  Celsius- Used in __________ community. The freezing point and boiling point of water is separated into 100 even intervals  Kelvin-  ____ is the lowest temperature called ____________ – all molecular motion stops

Measuring Temperature

Temperature Conversion Equations To convertUse the equationExample o C to o F o F = (9/5 x o c) + 32 See # 1 o F to o C o C = 5/9 x ( o F – 32) See # 2 o C to KK = o C See # 3 K to o C o C = K – 273 See # 4

Temperature Conversions  Convert 45 o C to o F  Convert 68 o F to o C

Temperature Conversions  Convert 45 o C to K  Convert 32 K to o C

More About Thermal Expansion  Expansion joints in highway bridges  Bridges heat up and ________ – this can cause the bridge to break so ___________________ are installed.  Hot air balloons  When the air inside is heated, it expands and becomes less ________. The balloon rises.

10.2 What is Heat?  TRANSFERRED THERMAL ENERGY  _______- The energy transferred between objects that are at different temperatures.  Energy is always transferred from the _________temperature to the __________temperature.  Stethoscopes “feel” cold because energy is transferred _______ from your back to the stethoscope.

Thermal energy is transferred Total kinetic energy of the particles that makes up the substance

3 Ways to Transfer Thermal Energy   Thermal Conduction is the transfer of thermal energy from one substance to another substance through _______________.  Thermal Conductor- Substances that can conduct thermal energy very ______. Ex:  Thermal Insulator- Substances that ________ conduct thermal energy well. Ex:

Ways to Transfer Thermal Energy   The transfer of thermal energy by the _____________of a liquid or a gas.  Warm air or liquid rises to the top because it’s less dense (high energy) At the surface, the warm air/liquid cools, condenses, and sinks back to the bottom.  This cycle is called a convection current

Ways to Transfer Thermal Energy   The transfer of energy by _______________, such as visible light and infrared waves.  This can occur in empty space.

Radiation and the Greenhouse Effect  Earth’s atmosphere acts like the windows of a ________  It allows the sun’s _______________to pass through it.  A greenhouse also traps _______, keeping the inside warm

Specific Heat  ___________-The amount of energy needed to change the temperature of 1 kg (or g) of the substance by 1 °C  Refer to table 2. Metal needs less energy to raise the temperature. Water needs more energy.  Heat can’t be measured directly  We need to use a formula. 

Specific Heat Calculations  How many joules does it take to heat 20. g of water from 10.0 to 40.0 o C?  (C p (water) = J/g o C )

Specific Heat Calculations  How much heat is required to heat 75 g of Iron (C p = J/gC o ) from 15.5 to 57.0 o C?

Specific Heat Calculations  How many joules does it take to change the temperature of 15 g of water 25 o C? (C p (water)_ = J/g o C )

10.3 Matter and Heat _______________ – the physical forms in which a substance can exist. The states of matter depend on the _______ of the particles. Gases = Liquids = Solids =

Changes of State  ___________A change of a substance from one state of matter to _______________.  PHYSICAL CHANGE!!! Include:  An ice cube that melts and then turns to a gas can be graphed on a temperature vs. energy graph.

Heat and Chemical Changes  Calorimeter-  When one object transfers thermal energy to another object, the energy ______________ object is ________ by the other object.  ________________- food is burned, energy released is transferred to the water, temp change of the water can be measured.  1 Calorie of food = ______J of energy.