Definitions
Define: Kinetic Energy
The energy of movement
Describe how particles move in a solid
Vibrate in place
Conduction is the transfer of heat through...
Direct contact with solids
Convection is the transfer of heat by...
the movement of particles in a fluid (liquid or gas)
Radiation is the the transfer of heat...
Through a empty space or a substance without heating that substance.
Define: Temperature
A measure of the average kinetic energy of the particles in an object
A balloon is placed in a freezer for 10 minutes. What happens to its size, and why?
The balloon shrinks because the air particles inside lose energy, move slower, and come closer together, reducing volume.
What type of materials are the best conductors of heat?
Metals: such as copper or aluminium
Why does warm air rise and cool air sink?
Warm air is less dense than cool air, causing it to rise. While cooler, denser air moves down.
How does the Sun heat the Earth?
The Sun emits infrared radiation, which travels through space and warms the Earth’s surface.
Define: Heat
The sum of the kinetic energy of the particles in an object (total kinetic energy)
How does the particle model explain heat transfer?
Heat transfer occurs when faster-moving particles collide with slower-moving particles, transferring kinetic energy.
Why does a metal spoon feel colder than a wooden spoon at room temperature?
Metal conducts heat away from your hand faster than wood, making it feel colder
What is a convection current?
A cycle of warm fluid rising and cool fluid sinking, creating a continuous flow of heat transfer.
Why do dark-colored objects absorb more heat than light-colored objects?
Because dark colours absorb more wavelengths of radiation and light colours reflect more wavelengths of radiation.
Define: Radiant Heat
the transfer of heat from a heat source (such as fire or the sun) to objects and people across empty space through electromagnetic waves.
How does the particle model explain why a metal expands when heated?
The particles move faster and push apart, increasing the size of the material.
You are pouring the same amount of hot water into two different cups: one made of metal and one made of ceramic. Which will cool down faster and why?
The metal cup will cool down faster because metal conducts heat away more efficiently than ceramic, which is an insulator.
How does convection help heat a room when using a radiator?
The radiator heats the air, making it rise, while cool air moves in to replace it, creating a convection current that distributes heat.
Explain the direction that radiant heat travels.
In straight lines outward from the heat source
Define: Thermal Equilibrium
Thermal equilibrium is the state in which two objects in contact no longer transfer heat because they have the same temperature.
A sealed can of deodorant explodes when thrown into a fire. Explain why using the particle model.
As the can heats up, the gas inside gains energy, causing the particles to move faster and spread apart. The increasing pressure eventually causes the can to burst.
Some cooking pots have copper bases, while others have stainless steel bases. Why do chefs prefer copper over stainless steel for heat conduction?
Copper is a better conductor than stainless steel, allowing heat to spread more evenly and quickly, preventing hot spots and making cooking more efficient.
Why does convection not occur in solids?
Convection requires particles to move freely, which can only happen in fluids like liquids and gases, not in solids where particles are fixed in place.
Why can radiation transfer heat through space, but conduction and convection cannot?
Radiation does not require particles to transfer heat, unlike conduction and convection, which need a medium to transfer energy.