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What is the boiling point of pure water?
100 degrees Celsius.
What is boiling?
Boiling is the rapid phase transition of a liquid into a gas (vapor) that occurs when it is heated to its specific boiling point, causing bubbles of vapor to form throughout the liquid.
What is evaporation?
Evaporation is the physical process where a liquid (most commonly water) changes into a gas or vapor, typically occurring at temperatures below the liquid's boiling point.
Multiple Choice: Which process is considered a "surface phenomenon" because it only happens at the top of a liquid.
A) Boiling
B) Condensation
C) Evaporation
D) Freezing
C) Evaporation
Give one example of evaporation in your daily life.
Give one example of boiling in your daily life.
True or False? Evaporation happens in all temperatures.
True
During __________, bubbles of gas form throughout the entire volume of the liquid, not just at the surface.
Boiling
Describe what happens to liquid particles during boiling.
When a liquid boils, its particles gain enough heat energy to move faster, break free from their tight bonds, and spread far apart to turn into a gas.
Describe what happens to liquid particles during evaporation.
During evaporation, liquid particles gain heat energy and move much faster . They vibrate so quickly that they break free from the surface and escape into the air as gas particles (water vapor). The particles move farther apart and turn from a liquid into a gas.
What factors affect the rate of evaporation? Choose one and explain why it affects evaporation.
Temperature: The hotter it is, the more energy particles have to escape. (Higher temp = Faster evaporation).Surface Area: A wider surface allows more particles to escape at once. (A spilled drink dries faster than one in a cup). Wind/Air Movement: Wind blows away the vapor already in the air, making room for more to escape. Humidity: If the air is already full of water (humid), it’s harder for more water to evaporate. (Clothes dry slowly on a sticky, humid day).
True or False: Boiling requires an external energy source to keep the temperature at the boiling point.
True
If you put a lid on a pot of water, will the water evaporate faster or slower? Why?
Slower. The lid traps the water vapor, making it harder for more molecules to escape into the air.
Which of the following factors will increase the rate of evaporation?
A) Decreasing the temperature
B) Increasing the surface area (spreading the liquid out)
C) Increasing the humidity in the air
D) Moving the liquid to a dark, cold room
B) Increasing the surface area
If you hang a wet towel outside on a sunny day, which process causes it to dry?
Evaporation
Evaporation is a ________ process, which is why dogs pant.
Cooling