Heat is a form of:

Everything in the universe has heat energy! Your BODY, your CAR…even ICE!

Temperature:  Temperature is ONLY a measurement.  Temperature measures the average kinetic energy of the molecules of an object or substance.

SUMMARY: HEAT IS ENERGY TEMPERATURE IS A MEASUREMENT

Temperature is measured with thermometers. There are several types of thermometers.

THERMOMETER TYPES: 1)Liquid Thermometer 2)Bimetallic strip 3)Digital

Liquid Thermometer Can only measure temperatures in a certain range. Uses the expansion of liquid alcohol or mercury (Hg) to indicate changes in temperature.

Bimetallic Strip A coil is made using two different metal strips pressed together Both strips expand and contract at different rates as the temperature changes As the temperature changes, the coil winds and unwinds

DIGITAL THERMOMETERS Measures temperature by noting the change in current Changes in temperature also cause electric current to change in a circuit

3 Main Temperature Scales 1)Celsius 2)Fahrenheit 3)Kelvin

What you need to know about the Fahrenheit Temperature Scale 1)Fresh water freezes at 32 degrees Fahrenheit 2)Fresh water boils at 212 degrees Fahrenheit

What you need to know about the Celsius Temperature Scale 1)Fresh water freezes at 0 degrees Celsius 2)Fresh water boils at 100 degrees Celsius 3)It is the commonly used scale except for in the United States

What you need to know about the Kelvin Temperature Scale 1)There are NO NEGATIVE NUMBERS 2)Based on absolute zero (all molecule movement has stopped). 3)The size of a Kelvin degree is equal in magnitude (size) to a Celsius degree.

Heat moves from objects with higher energy to objects with lower energy DEMO-Is it hot or is it cold?

HEAT CAN MOVE IN 3 WAYS 1)CONDUCTION 2)CONVECTION 3)RADIATION

For heat to be transferred by conduction:  objects must be in direct contact with each other—  THEY MUST BE TOUCHING!!!

Convection:  Transfer of energy by the movement of fluids with different temperatures  For it to be fluid, it can be a liquid or a gas!

Radiation:  Transfer of energy by electromagnetic waves  NO DIRECT CONTACT!!!  Does not require a medium to travel!  It is the only way solar heat energy can travel to Earth!

Some objects act as conductors and some act as insulators. A conductor is a material that transfers heat quickly An insulator is a material that slows the transfer of heat

Specific Heat  Describes how much energy is required to raise an object’s temperature.  The specific heat value is how much energy is required to raise 1 kg. of a substance by 1 degree Kelvin  Denoted by “c” in calculations

Specific Heat Equation Energy = (specific heat) x (mass) x (temperature change) OR energy = cm t

When the temperature of a substance is increased, its molecules move faster and usually move farther apart. This is thermal expansion. It occurs in all forms of matter (there are a few exceptions). Water is an exception – it expands when it is cooling from 4 degrees C to 0 degrees C.

To raise indoor air temperature on a cold day, energy must be transferred into a room’s air by a heating system. Heating system – Any device or process that transfers energy to a substance to raise the temperature of the substance.

Types of Heating Systems:  Forced Air Systems  Radiator Systems  Electric Heating Systems

Heating and Work increase thermal energy  You can warm your hands by either placing them near a heat source or rubbing them together  In this example, your hands would be considered to be a system.  A system can be a group of objects you can draw a boundary around to consider certain values about a scenario.

THERE ARE 2 TYPES OF SYSTEMS:  OPEN-Thermal energy can flow across your “boundary” or if work is done across the boundary  CLOSED – Thermal energy is contained within the “boundary” and no outside work is done.

First Law of Thermodynamics The increase in the thermal energy of a system equals the work done on the system plus the thermal energy transferred to the system

Second Law of Thermodynamics Energy moves from warmer objects (higher energy) to cooler objects (lower energy)

Cooling System – A device that transfers energy as heat out of an object to lower its temperature. Cooling Systems use evaporation to transfer energy from their surroundings using a refrigerant Refrigerant – A substance used in cooling systems that transfers large amounts of energy as it changes state