Conduction
When a warm object touches a cooler one, what happens to the energy between them?
Energy transfers from the warmer object to the cooler one.
What happens to water molecules during evaporation?
They gain enough energy to escape the liquid and become gas.
When water vapor turns into liquid, what process is happening?
Condensation.
What happens to liquid water when it freezes?
Its molecules slow down and become locked in fixed positions.
What causes ice to melt into liquid water?
Molecules gain enough energy to move out of their fixed positions.
In conduction, which particles pass energy to others?
Fast-moving particles transfer energy to slower-moving ones.
Can water evaporate at room temperature?
Yes, because some molecules move fast enough to break free even without boiling.
What happens to the motion of water molecules during condensation?
They slow down and come closer together.
Why does ice float on water?
Because its molecules are arranged farther apart, making it less dense.
How does the arrangement of molecules change when ice melts?
They go from an orderly pattern to a more random, sliding arrangement.
What happens to the molecules in your finger when you touch ice?
They slow down as heat leaves your finger and enters the ice.
Why does warm water evaporate faster than cool water?
Because heat gives more molecules the energy needed to overcome their attractions and escape.
Why do water droplets form on the outside of a cold glass on a humid day?
Warm water vapor in the air cools, slows down, and sticks together as liquid.
Why should you leave space at the top of a bottle before freezing water?
Because water expands when it freezes and could burst the container.
Why does heat speed up the melting process?
It increases molecular motion, breaking the bonds that hold the solid together.
Why does a metal spoon in hot soup get hotter over time?
Because energy moves by conduction from the fast-moving soup molecules to the slower-moving spoon molecules.
In an experiment comparing warm and cool water, which will lose mass faster and why?
The warm water, since more molecules have enough energy to evaporate.
What effect does cooling water vapor have on the rate of condensation?
Cooling increases the rate because slower molecules can stick together more easily.
Why does water expand instead of contract when it freezes?
The shape and attractions of water molecules make them form a structure that’s less tightly packed.
In an experiment to make ice melt faster, why do you need two pieces of ice?
One acts as a control to compare the results.
Explain how conduction causes both objects in contact to change temperature.
The warmer one loses energy and cools down while the cooler one gains energy and warms up until they reach the same temperature.
How does adding or removing energy affect the rate of evaporation?
Adding energy speeds up evaporation; removing energy slows it down.
How can you test whether the water on a cold cup comes from the air or from inside the cup?
Seal a cold cup in a bag with no air; if no moisture forms, it shows the droplets come from water vapor in the air.
Why do different liquids have different freezing points?
Because the strength of attraction between their molecules varies.
What’s the main difference between regular ice and dry ice when heated?
Water ice melts into liquid, but dry ice changes directly from solid to gas.