Unit 2: Heat
Chapter 5 Temperature describes how hot or cold an object Is.
Facts of Temperature Temperature describes how “hot” or “cold” something is. Temperature is the measurement of one object’s kinetic energy at one specific time. - energy is the power that enables an action to take place. Temperature is measured in units called degrees (0 o ). Scales may be in Celsius, Fahrenheit or Kelvin.
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 sun’s surface, but both are hot. vs. The sun is hotter than a burning match.
The Laboratory Thermometer C = Boiling point of water. 37 o C = Average human body Temperature 20 o C = Room Temperature Range 0 o C = Freezing point of water Any temperatures below 0 o C is referred to as a subzero temperature
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.
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.
How Does Temperature? … cont. Decrease of Body Temperature When the average body temperature decreases, significantly, hypothermia may occur. Shivering is the body’s natural mechanism to warm the body by moving.
Types of Heat measuring Devices Thermometer –Thermo means “Heat”. –Meter means “measuring device” –Heat measuring device Bimetallic Strip Thermocouple Infrared Thermograph
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.
Chapter 5 Scientist use the particle theory of matter to describe temperature.
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.
Energy Kinetic Energyvs.Potential Energy (Energy in Motion)(Energy at rest)
States of Matter SolidLiquidGas - Fixed Shape- Changes shape- Changes shapewith container - Forms a surface- No surface
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.
Changing States of Matter
Changes in Matter - Points Freezing point Boiling Point Melting Point ** Heating Curves **
Chapter 6 Heat is transferred from one place to another by three different processes 1.)Conduction 2.)Convection 3.)Radiation
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
Convection Process by which moving warm liquid or air moves/carries heat to other areas. Convection current
Radiation Heat carries electromagnetic waves of energy from one location to another.
Solar Radiation
Types of Electromagnetic Waves Radio Waves Microwaves Infrared Waves Visible Light Ultraviolet Waves X-rays Gamma Rays
Heating Home Solar Energy Geothermal Energy Electric Energy Burning of Fossil Fuels **Conductors and Insulators
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.
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
Conductors – student examples Steel rod for fire place Copper tubing Wire Cooking pot Iron frying pan Kettle pot Sand