Buzz
When left untouched, a bottle of purified water won't freeze until it drops to a chilling minus 43.6 degrees Fahrenheit (minus 42 degrees Celsius), entering the state of supercooled liquid. MytourYou might have witnessed the mesmerizing sight of a regular cold water bottle sitting still, seemingly innocent, until bam! A tap on the table, and the entire bottle solidifies into ice. What's behind this mysterious phenomenon?
It's not sorcery—it's science that makes the bottled water freeze completely, and it's actually quite simple science. So, how long does water need to freeze? Let's explore.
The Enigma of Nucleation
Any time a substance transitions between states — like when water turns from liquid to solid — nucleation plays a vital role. It is the catalyst that forms the first ice crystal and sets off the rapid growth of many others.
The Mechanism of Heterogeneous Nucleation
This occurs when foreign particles, such as dust, are present in the water, creating a nucleus that facilitates ice formation as the temperature falls. As the process continues, ice crystals form throughout the liquid, eventually transforming it into solid ice.
The Process of Homogeneous Nucleation
Pure water, lacking impurities, doesn't have a nucleus to trigger freezing. As a result, it becomes supercooled. This allows it to freeze almost instantly when exposed to a foreign nucleus, creating the fascinating phenomenon of "instant" ice.
Fun Facts About Freezing Points
Water typically freezes at 32°F (0°C). However, when it's purified and free from impurities, it needs even colder temperatures to freeze.
If you place bottles of purified water in a freezer for several hours, they'll remain liquid, because pure water with no nuclei freezes at a chilling -43.6°F (-42°C). This makes it a supercooled liquid — pretty amazing, right?
Time to Create Some Instant Ice!
Ready to freeze some water? Grab a few bottles and place them in your freezer. Let them sit undisturbed for a couple of hours, allowing the water to reach the supercooled state. How long should you wait? Generally, it's about two-and-a-half to three hours.
After the wait, carefully remove the bottles. Now, give one a shake or tap it on the table.
At this point, almost anything can act as a nucleus — whether it's air bubbles, a tiny dent, or any slight disturbance. A small change is enough to trigger homogeneous nucleation. Once disturbed, the water molecules will freeze so rapidly that it appears instant.
If you prefer not to shake or tap the bottle, you can pour the supercooled water onto an ice cube. The cube acts as the nucleus, allowing you to create a tiny tower of ice as you pour.
Quick Freezing FAQs and Myth Busting
Which one freezes faster: hot or cold water?
The Mpemba effect is a fascinating phenomenon where, under certain conditions, hot water can freeze more quickly than cold water. Surprising, isn't it?
Do the type of ice trays make a difference in how fast water freezes?
Definitely! A metal tray, for example, might speed up the freezing process since metal conducts heat better (or lacks it). But larger ice cube trays could take longer to freeze because of the increased volume of water.
What’s the best water to use for making instant ice?
For this freezing experiment, bottled or purified water is usually the most ideal choice, though tap water can also work depending on how it has been treated.
