Unit 2: Heat

1
Unit 2 Heat

2
Chapter 5

• Temperature describes how hot or cold an object
  Is.

3
Facts of Temperature

• Temperature describes how hot or cold
  something is.
• Temperature is the measurement of one objects
  kinetic energy at one specific time.
• - energy is the power that enables an action to
  take place.
• Temperature is measured in units called degrees
  (0o). Scales may be in Celsius, Fahrenheit or
  Kelvin.

4
The Description of Temperature is Relative

• An ice-cube is warmer than liquid nitrogen, but
  both are cold.
• vs.
• Liquid nitrogen is colder than an ice-cube.
• A burning match is cooler than suns surface, but
  both are hot.
• vs.
• The sun is hotter than a burning match.

5
The Laboratory Thermometer

• 1000C Boiling point of water.
• 37o C Average human body Temperature
• 20oC Room Temperature Range
• 0oC Freezing point of water
• Any temperatures below 0oC is
• referred to as a subzero
• temperature

6
Thermometer

• A thermometer may be used to measure
• - daily temperature of the atmosphere for
  accurate weather reporting.
• - human body temperature when sick.
• - temperature of food for cooking meat.
• - temperature of house for comfort.

7
How Does Temperature affect the Human body?

• Increase of Body Temperature
• When the average body temperature increases a
  fever may develop. A fever is a natural body
  defense against viral or bacterial infection.
  These infections can not survive the increase of
  body temperature.
• Sweating is a way for the body to cool itself.

8
How Does Temperature? cont.

• Decrease of Body Temperature
• When the average body temperature decreases,
  significantly, hypothermia may occur.
• Shivering is the bodys natural mechanism to warm
  the body by moving.

9
Types of Heat measuring Devices

• Thermometer
• Thermo means Heat.
• Meter means measuring device
• Heat measuring device
• Bimetallic Strip
• Thermocouple
• Infrared Thermograph

10
Some facts on Heat

• Heat is energy
• White light is the hottest
• Heat will always travel to the coldest object.
  When you fell something hot, heat is transferring
  into you. When you feel something cold, heat is
  transferring out of you.
• Heat is everywhere.

11
Chapter 5

• Scientist use the particle theory of matter to
  describe temperature.

12
The Particle Theory

• All matter is made up of tiny particles
• These particles are always moving the have
  energy.
• - The more energy that is added to particles the
  faster they move.
• There are spaces among particles
• There are attractive forces between particles.
• The particles of one substance differs from the
  particles of a different substance.

13
Energy

• Kinetic Energy vs. Potential Energy
• (Energy in Motion) (Energy at rest)

14
States of Matter

• Solid Liquid Gas
• - Fixed Shape - Changes shape - Changes shape
• with container with container
• - Forms a surface - No surface

15
Expansion and Contraction

• Thermal Expansion
• The volume of an object of substance increases
  as energy (heat) is added to it.
• Particle of matter become active, moving out from
  each other
• Thermal Contraction
• The volume of an object or substance decreases
  as energy (heat) is taken away from it.
• Particles of matter tend towards inactive.

16
Changing States of Matter

17
Changes in Matter - Points

• Freezing point
• Boiling Point
• Melting Point
• Heating Curves

18
Chapter 6

• Heat is transferred from one place to another by
  three different processes
• 1.) Conduction
• 2.) Convection
• 3.) Radiation

19
Conduction

• Heat is transfered from warmer parts of an
  object to more cooler parts via particles.
• Heat from the hot part of the rod closer to the
  fire is conducted (travels) to the part of the
  rod being held by the hand

20
Convection

• Process by which moving warm liquid or air
  moves/carries heat to other areas.
• Convection current

21
Radiation

• Heat carries electromagnetic waves of energy from
  one location to another.

22
Solar Radiation

23
Types of Electromagnetic Waves

• Radio Waves
• Microwaves
• Infrared Waves
• Visible Light
• Ultraviolet Waves
• X-rays
• Gamma Rays

24
Heating Home

• Solar Energy
• Geothermal Energy
• Electric Energy
• Burning of Fossil Fuels
• Conductors and Insulators

25
Temperature vs. Heat

• Heat is related to the total kinetic energy of
  particles. Heat is the transfer of energy from a
  hot object to a colder object.
• Temperature is related to the average kinetic
  energy of particle.

26
Insulators student examples

• Insulators in houses help keep energy in and the
  cold out during the winter months. In the summer
  insulators help keep the coolness in and the
  warmth out.
• Sawdust keeps ice from melting
• Newspaper insulators in attic
• Clothes
• Mud for adobe houses
• Pink, blue or yellow insulation in house
• Feathers in winter jackets

27
Conductors student examples

• Steel rod for fire place
• Copper tubing
• Wire
• Cooking pot
• Iron frying pan
• Kettle pot
• Sand