Thermodynamics: The Physics of Heat

Mr. Miller

**Physics of Heat – Study Guide**

**Things you need to know:**

- Memorize the following formulas, know what they mean, and how to use them to calculate any missing variable:
**Δ****L =****a****L****Δ****t**- ΔL = change in length
- a
- L = original length
- Δt = change in temperature
**Q = cm****Δ****t**- Q = amount of heat, measured in calories
- c = specific heat, measured in cal/g°C
- m = mass, measured in grams
- Δt = change in temperature, measured in °C
**Density = mass/volume****Thermal Capacity = specific heat x mass****°F = (9/5 x °C) + 32****°C = 5/9 x (°F – 32)**

**Be able to remember major aspects from each lab and demonstration, particularly observations and conclusions**

**Many questions on the final exam will be taken from previous quizzes – REVIEW YOUR QUIZZES**

- Understand and be able to apply the concepts of:
- Sensation of warmth depends upon:
- Initial temp of skin and object
- Heat conductivity of skin and object
- How long the skin and object are in contact
- Sensitivity of the skin (number and type of nerve endings)
- Melting point
- Freezing point
- Boiling point
- Condensing point
- The three ways heat moves: Conduction, Convection, Radiation, with examples for each
- How a Thermos minimizes heat transfer
- The concept of Latent heat of vaporization (liquid to gas) and fusion (solid to liquid)
- Latent heat of vaporization for 1g of water is 540 cal
- Latent heat of fusion for 1g water is 80 cal
- Expansion of materials under heat (solids, liquids, gasses)
- Heat conductivity, examples of substances with high and low heat conductivity
- Specific heat as amount of heat required to raise 1g of a substance by 1°C
- The special properties of water:
- Exists as solid, liquid and gas (ice, water, steam) in the range of normal Earthly temperatures
- Density of water greatest at 4°C and consequences of this fact for freezing lakes and oceans
- Density of water is
*defined*as 1 gram/ml - Specific heat of water is
*defined*as 1 cal/g°C - Fahrenheit and Celsius temperature scales with major points for water in each and body temperature
- How to use the formulas to convert from °C to °F and back and between °C and °K
- The scientific method’s stages (Have a question about the world, Hypothesis, Experiment, Revise Hypothesis, Repeat)
- Stages of how to write up a lab (Intro/Purpose, Materials, Procedure, Observations/Data, Analysis/Conclusion)
- How to convert from decimal to scientific notation
- How to convert from scientific notation to decimal
- Convection and its relationship to density
- Difference between heat and temperature
- The concept of a calorie and a food Calorie (food Calorie is 1000 calories)
- Thermal capacity – a measure of how much heat a mass can contain relative to others at the same temperature
- Relationship of pressure and temperature
- Relationship of pressure and volume
- Relationship of volume and temperature
- How these three fit together in Boyle’s Law: Tk=PV
- The basic idea behind how steam engines and 4 stroke combustion engines work
- How a refrigerator works