🌡️ • Lesson 3.3 : Thermal Physics, Kinetic (Phys) Flashcards
During this lesson, we will go through particle model, pressure changes, thermal properties and temperature; melting, boiling and evaporation, as well as conduction, convection, and radiation.
What is Brownian motion?
The random motion of particles (ex. smoke or pollen) caused by collisions with much smaller, faster-moving particles in the surrounding gas or liquid.
What is the pressure of a gas?
Gas pressure is caused by particles colliding with surfaces, creating a force per unit area.
How does temperature affect the pressure of a fixed mass of gas at constant volume?
As temperature increases, the particles of the gas move faster, colliding with the walls more frequently and with greater force, increasing the pressure.
How does volume affect the pressure of a fixed mass of gas at constant temperature?
When volume decreases, particles collide more frequently with the walls, increasing pressure.
When volume increases, collisions are less frequent, decreasing pressure.
What is thermal expansion in solids, liquids, and gases at constant pressure?
Temperature increases = particles move faster and spread apart.
In solids, this causes the material to expand.
In liquids and gases, the expansion is more pronounced as particles can move more freely.
What are some everyday applications and consequences of thermal expansion?
Railway tracks: Gaps are left to prevent tracks from buckling in the heat.
Bridges: Expansion joints allow for stretching and shrinking due to temperature changes.
Melting and boiling temperatures of water? (Standard AP)
Melting point: 0°C
Boiling point: 100°C
What is the difference between boiling and evaporation?
Boiling: Happens throughout the liquid at a specific temperature (100°C for water).
Evaporation: Occurs at the surface at any temperature below boiling.
How do condensation and freezing occur in terms of particles?
Condensation: Gas particles lose energy, slow down, and bond together to form a liquid.
Solidification (Freezing): Liquid particles lose energy, slow down, and arrange in a fixed, regular pattern to form a solid.
How do temperature, surface area, and air movement affect evaporation?
Temperature: Higher temperature increases evaporation.
Surface area: Larger surface area increases evaporation.
Air movement: Increased airflow removes vapor, increasing evaporation.
How does evaporation cause cooling?
Evaporation removes the ‘more energetic’ particles from the surface of the liquid, which lowers the average energy of the remaining particles, cooling the liquid.
How do melting and boiling involve energy input without a change in temperature?
Energy is used to break the bonds between particles, without changing the temperature.
What are examples of good and bad thermal conductors (insulators)?
Good conductors: metals (e.g., copper, aluminum).
Bad conductors (insulators): wood, plastic, rubber.
How does thermal conduction work in solids?
In solids, heat is transferred through atomic vibrations and the movement of free electrons in metals.
What is convection in liquids and gases?
Convection occurs when heated particles become less dense and rise, while cooler, denser particles sink, creating a flow of heat.
How does thermal radiation transfer energy?
Thermal radiation transfers energy through infrared radiation without needing a medium.
How does surface color and texture affect thermal radiation?
Black, dull surfaces absorb and emit radiation better, while white, shiny surfaces reflect more radiation.
How can you test good and bad emitters of thermal radiation?
Use a temperature sensor to measure how fast different materials heat up or cool down.
Dark, matte surfaces emit radiation faster than light, shiny ones.
How can you test good and bad absorbers of thermal radiation?
Expose different materials to heat and measure how much their temperature rises.
Dark, matte materials absorb more heat.
