Download Chapter 10: Heat Energy

CHAPTER 10: HEAT ENERGY
TEMPERATURE AND HEAT
HOW IS ENERGY RELATED TO MOTION?
• The words hot, warm, cool, and cold are
words used to describe the temperature of
something.
• Temperature is determined by the
movement of molecules or atoms.
• Any moving object, has energy due to its
motion.
• This energy is not a fluid that can flow from
the moving object, nor is it any kind of
matter we can pluck from the moving
object.
• Energy- the ability to move other material
around. Whether it be an object or its
atoms.
WHAT ARE THE TWO MAIN KINDS OF ENERGY?
• Energy cannot be created or destroyed, it only
changes form.
• There are two main kinds:
• Kinetic Energy- The energy of any moving object.
• Potential Energy- Energy stored in an object of
material.
• Moving an object upward is a way to give potential
energy.
• Chemical binds also are a source of potential energy.
• Energy is measured in Joules.
• Joule- the amount of kinetic energy gained by a 1kilogram object falling from a height of 10.2
centimeters.
WHAT IS TEMPERATURE?
• Molecules in a material move about at different speeds.
• They have an average speed and most molecules have
speeds near the average, while only a few molecules travel
at speeds far above or below the average.
• The average speed of the molecules in a material
determines the molecules’ average kinetic energy.
• Temperature- The average kinetic energy of the
molecules.
• This determines how hot or cold the object is.
• Use thermometers to measure temperature.
WHAT IS HEAT?
• Energy always flow from the hotter object to
the cooler one, never the reverse.
• Energy will continue to flow until the two
object reach the same temperature.
• When the objects are both at the same
temperature, their molecules will have the
same kinetic energy.
• Heat- a form of energy. Measured in energy
units such as Joules.
WHAT IS RADIATION?
• Radiation- The transfer of energy by
electromagnetic waves.
• All objects give off a wide variety of waves.
• Types: infrared, visible, and ultraviolet.
• Examples:
• The Sun
• Microwave
• Electric Stove
• Sometimes you can see the waves give off a color,
the higher the temperature of the waves, the
more you can see its heat.
WHAT IS CONDUCTION?
• Conduction- The movement of energy through direct
contact.
• Example:
• The burner on a stove is very hot, which means its atoms
are moving very, very, fast.
• When these fast moving atoms, hit the pan, the pan’s
atoms move faster .
• When the pan’s atoms hit the molecules in the sauce,
the sauce molecules heat up, making the sauce hotter.
WHAT IS CONVECTION?
• Convection- The transfer of energy by the flow of a
liquid or gas.
• Heat is transferred by having hot liquid/gas rise, and
then sink when it cools.
• Examples:
• Lava Lamp
• Boiling Liquid
• Heating of the atmosphere
• The heating of the center of the Earth.
DO SOME MATERIALS WARM FASTER THAN OTHERS?
• Equal masses of different materials have a different
temperature change for the amount of heat absorbed.
• The rate that a material heats up is a physical
property.
• We can use it to tell one substance from another.
• Metals are good at heating fast.
• Water takes longer to heat. It stays cooler longer, so
water is said to be a good coolant.
WHAT IS INSULATION?
• Insulation- Preventing heat from flowing in or out
of a material.
• You insulate something by wrapping it securely with
a material that is not a good conductor of heat.
• There are many instances in our everyday lives
where it is important to keep heat from entering or
leaving something.
• Examples:
• Houses are insulated.
• Thermoses and coolers are insulated.