5-3 What is freezing point?
SWBAT: Identify the freezing point and melting point of a substance.
freezing point: temperature at which a liquid changes to a solid
melting point: temperature at which a solid changes to a liquid
• Removing heat from a liquid at its freezing point changes the liquid into a solid.
• Absolute zero (about –273˚C) is the lowest possible temperature.
• The temperature at which a solid changes to a liquid is called its melting point.
• The freezing point and melting point of water are the same—0˚C.
Discussion Questions:
1. Define: What is the freezing point of water?
2. State: What is the freezing point of ethyl alcohol?
3. Describe: What happens to the particles of a substance as the temperature nears absolute zero?
4. State: What is the melting point of water?
Checking Concepts
1. What happens when water freezes?
2. At what temperature does water begin to freeze?
3. What is the temperature called at which all particle motion almost stops?
4. What is the melting point of ice?
Thinking Critically
5. Hypothesize: The water in a lake has just reached 0 degrees Celsius. Explain why it may not be safe to go ice skating on the lake.
6. Compare: How are melting point and freezing point different? How are they alike?
freezing point: temperature at which a liquid changes to a solid
melting point: temperature at which a solid changes to a liquid
• Removing heat from a liquid at its freezing point changes the liquid into a solid.
• Absolute zero (about –273˚C) is the lowest possible temperature.
• The temperature at which a solid changes to a liquid is called its melting point.
• The freezing point and melting point of water are the same—0˚C.
Discussion Questions:
1. Define: What is the freezing point of water?
2. State: What is the freezing point of ethyl alcohol?
3. Describe: What happens to the particles of a substance as the temperature nears absolute zero?
4. State: What is the melting point of water?
Checking Concepts
1. What happens when water freezes?
2. At what temperature does water begin to freeze?
3. What is the temperature called at which all particle motion almost stops?
4. What is the melting point of ice?
Thinking Critically
5. Hypothesize: The water in a lake has just reached 0 degrees Celsius. Explain why it may not be safe to go ice skating on the lake.
6. Compare: How are melting point and freezing point different? How are they alike?