Heat and Temperature Chapter 16 P. Sci. Unit 4 cont.

What is Temperature? Particles (atoms and molecules) within a substance are constantly moving (kinetic energy) Particles (atoms and molecules) within a substance are constantly moving (kinetic energy) Temperature is the Temperature is the _________________ _________________ _________________

What is Temperature cont. As kinetic energy increases, ___________ __________________. As kinetic energy increases, ___________ __________________. Thermometers- expand as temperature increases and contracts as temperature decreases. Thermometers- expand as temperature increases and contracts as temperature decreases.

Measuring Temperature Units for temperature can be __________ __________

Fahrenheit Freezing point: ____ Freezing point: ____ Boiling point: _____ Boiling point: _____ American scale – rarely used in science

Celsius Also known as Centigrade Also known as Centigrade Freezing point: ___ Freezing point: ___ Boiling point: ____ Boiling point: ____ 1°C= about 2°F 1°C= about 2°F

Kelvin SI unit to measure SI unit to measure temperature temperature 0 K is absolute zero= 0 K is absolute zero= ____________ ____________ Energy is minimal and Energy is minimal and cannot go any lower cannot go any lower Converting Celsius to Kelvin: Converting Celsius to Kelvin: –1K= 1 °C Kelvin= Celsius or K= T C - 273

Energy Transfer Temperature is energy transferred as _____. Temperature is energy transferred as _____. Energy must move for heat to occur. Energy must move for heat to occur.

Energy Transfer cont. Heat: transfer of energy between the particles of 2 objects ____________ ______________. Heat: transfer of energy between the particles of 2 objects ____________ ______________. Heat flows from ____ __________ (energy) to _____________ (energy) Heat flows from ____ __________ (energy) to _____________ (energy)

Examples of energy transfer Freezing water for ice Freezing water for ice Dew evaporating in morning sunlight Dew evaporating in morning sunlight Heating water for a shower Heating water for a shower

Types of Energy Transfer 1. Conduction: ___________; 2 objects in contact are at unequal temperatures

2. Convection: movement of warm ________.  Movement of the heated substance (liquid or gas)  Convection Current: cycle of a heated fluid that rises, cools, and falls

3. Radiation: no physical contact needed.  Transfer of energy through ____________ ____________ (infrared, visible light, ultraviolet)  No movement of matter –Example: standing in sunlight

Conductors Any material through which energy is easily Transferred. Any material through which energy is easily Transferred. ex: __________ ex: __________

Usually solid metals because their molecules are tightly packed. Usually solid metals because their molecules are tightly packed. Gases and liquids are poor conductors because the molecules are not as tightly packed together. Gases and liquids are poor conductors because the molecules are not as tightly packed together.

Insulators Slow down Slow down heat transfer heat transfer Poor conductors Poor conductors Examples: ____________ Examples: ____________

Specific Heat The amount of energy needed to raise 1kg of a substance by 1 K The amount of energy needed to raise 1kg of a substance by 1 K Q= _____________ Q= _____________ – Q = heat – c = specific heat – m= mass – Δt= change in temperature –SI unit is J/kg●K or J/kg●◦C

Remember… Remember… – energy is always ___________. ___________. – Energy is transferred from higher temperatures to lower temperatures. – Insulation minimizes unwanted energy transfers in walls, attics, etc.

Heating System Heating System: any device or process that transfers energy to a substance to ____________ _____________. Heating System: any device or process that transfers energy to a substance to ____________ _____________.

Cooling Systems Transfers heat energy out of an object to ______ ____________. Transfers heat energy out of an object to ______ ____________. Evaporation Evaporation Condensation Condensation Heat pumps Heat pumps

1. What is temperature? 2. Name the 3 different scales with which temperature is measured. 3. Convert 51°C to Kelvin.

4. Convert 324K to Celsius. 5. Name 3 methods of energy transfer and explain how they work. 6. Explain the difference between conductors and insulators and insulators