Changes of state

Vocabulary flashcards covering key terms from the Week 3 Respiratory Physics notes, including temperature conversions, energy concepts, phase changes, humidity, heat transfer, and gas/liquid properties.

Fahrenheit to Celsius conversion

C = (F − 32) / 1.8

Celsius to Fahrenheit conversion

F = (1.8 × C) + 32

Celsius to Kelvin conversion

K = C + 273

Potential energy

Stored energy

Kinetic energy

Energy in motion

Exothermic

Releasing energy to its surroundings

Endothermic

Absorbing energy from its surroundings

Thermodynamics

Science of energy, heat, work, and their relationships in systems at various temperatures

Energy

The ability to do work; requires transfer of energy for change (endo/exothermic processes)

Heat

Total thermal energy of an object

Temperature

Measurement of the average thermal energy; related to molecular speed and collisions

Thermal energy

Energy associated with hot objects

Heat capacity

Amount of thermal energy needed to raise or lower the temperature of an object by 1C

Specific heat capacity

Amount of thermal energy needed to raise or lower the temperature of 1 gram of a material by 1°C

Thermal expansion (solids)

expands in length, width, and height with increased temperature

Liquids

expands in all directions with increased temperature

Gases

increase in volume (and often pressure) with temperature rise due to faster molecular motion

Condensation

Gas to liquid (or solid) phase change (water on cold cup)

Freezing

Liquid to solid phase change (water to ice)

Sublimation

Solid to gas phase change (dry ice)

Melting

Solid to liquid phase change (ice to water)

Evaporation

Liquid to gas below the boiling point; rate depends on temperature and air conditions (puddle disappearing after it rains)

Boiling

Vaporization at the boiling point

Absolute humidity

Water vapor content in air; actual amount or weight of water vapor in a gas (mg/L); varies with temperature and pressure

Absolute humidity in ideal conditions

43.8 mg/L when fully saturated

Relative humidity

Actual vapor pressure as a percentage of the saturated vapor capacity: (actual/saturated) × 100 (Ratio) RH%

Dew point/Condensation

condensation is when gas begins to condense into liquid when cooled

Conduction

Heat transfer by direct contact (e.g., touching a cold surface)

Convection

Heat transfer by movement of fluids (gases or liquids) ex. warm air heating water, wind and ocean currents

Radiation

Heat transfer by infrared waves (no direct contact needed) ex. Heated wires in ventilator make it so the warm water doesn’t lose heat before getting to pt.

Pressure

Force per area; depends on height, weight, and density characteristics of a system

Buoyancy

Upward force on an object submerged in a fluid due to pressure differences; explains why solid objects float or suspend in gasses (e.g., aerosols)

Specific gravity

Ratio of the density of a substance to the density of a reference substance (usually water)

Viscosity

force opposing fluid's flow (resistance to movement)

-directly proportional to cohesive forces

-more energy used for thicker liquids

ex. blood has a viscosity 5 times greater than water

blood is thicker because it has more substances like rbc and proteins. more rbc means thicker the blood.

not enough oxygen makes blood thicker like in copd patients

Cohesion

Attractive force between like molecules

Adhesion

Attractive force between unlike molecules

Surface tension

Tension at the surface of a liquid due to cohesive forces; allows bubbles to retain shape

Latent heat

Heat absorbed or released during a phase change without a change in temperature

Perfect breath from vent

Cold, dry o2

energy pushes gas forward

humidifier: conduction heats water, Evaporation adds moisture (latent heat)

Heated circuit: convection carries warm moist gas, heated wires use conduction to fight heat loss from radiation.

pt. receives gas at 37c and 100% humidity