Freezing Point - Definition, Examples, Quiz, FAQ, Trivia
Discover how temperature changes transform liquids to solids
What is Freezing Point?
Freezing point is the specific temperature at which a liquid turns into a solid. This happens because the molecules slow down and arrange themselves into a fixed pattern.
Key facts about freezing point:
• Every liquid has its own freezing point
• For pure water, freezing point is 0°C (32°F)
• Freezing is a physical change, not chemical
• Adding substances to a liquid changes its freezing point
Think of freezing point like a special temperature doorway. When the temperature drops below this doorway, liquids walk through and become solids!
Key Concept
Freezing point is the temperature where a substance changes from liquid to solid. This change happens because molecules slow down and form organized structures.
Liquid state
(Water flows)
Phase change occurs
(Water ↔ Ice)
Solid state
(Ice forms)
Freezing Point of Water
Pure water freezes at exactly 0°C (32°F) at sea level. But this temperature can change depending on:
Factors affecting water's freezing point:
• Impurities: Adding salt or sugar lowers freezing point
• Pressure: Higher pressure slightly lowers freezing point
• Container: Smooth containers can supercool water
• Movement: Moving water freezes at lower temperatures
Did you know that water is special because its solid form (ice) is less dense than liquid water? That's why ice floats!
Liquid Water
Above 0°C (32°F)
Molecules move freely
Ice
Below 0°C (32°F)
Molecules form crystals
Supercooling Phenomenon
Pure water can sometimes stay liquid below 0°C in a process called supercooling. But when disturbed or when an ice crystal is added, it instantly freezes!
Freezing Point Depression
Freezing point depression occurs when we add substances to a liquid, causing it to freeze at a lower temperature. This is why we use salt on icy roads in winter!
How it works:
• Adding salt to water disrupts the formation of ice crystals
• The more salt you add, the lower the freezing point
• Seawater (with salt) freezes at about -2°C (28°F)
• Car antifreeze works the same way
Freezing point depression isn't just for salt - any dissolved substance will lower the freezing point. This is why fruit doesn't freeze solid at 0°C - it contains sugar!
Salt on Roads
Salt lowers freezing point to about -9°C (15°F), melting ice on roads
Antifreeze
Car antifreeze lowers water's freezing point to protect engines
Food Science
Ice cream stays soft at freezing temperatures because of sugar content
Ocean Water
Seawater freezes at about -2°C (28°F) due to dissolved salts
Freezing Point Quiz
Test your knowledge of freezing point with this 5-question quiz. Choose the correct answer for each question.
Frequently Asked Questions
Here are answers to common questions about freezing point:
Science Trivia
Discover amazing facts about freezing point:
Super Cold Water
Scientists have supercooled water to -42.55°C (-44.59°F) without it freezing! This happens when water is extremely pure and undisturbed.
Ocean Ice
Seawater freezes at about -2°C (28°F) because of its salt content. When ocean water freezes, the ice contains very little salt - most salt is pushed out as ice forms.
Space Freezing
In outer space, water would boil first and then freeze! This happens because of the vacuum and low pressure in space.
Coldest Recorded
The coldest natural temperature ever recorded on Earth was -89.2°C (-128.6°F) in Antarctica. At this temperature, even antifreeze would freeze solid!
