A Science Fair Experiment

Instant Freeze Water

Instantly Frozen Water Experiment (Poulter, N.d.)

There is a common phenomenon that has been experienced by many people. During the winter, if you leave a bottle of water in a car, garage, or other cold place overnight then something quite interesting can happen -- then the cap is opened, the liquid can freeze instantly. This experiment reproduces this phenomenon using a few simple materials and also explains the science behind what is going on relative to the "instant freeze water." "

The materials needed for the experiment include (Wells, 2013):

Seltzer water -- flavored or plain in plastic bottles. Do not use glass bottles as the liquid may accidentally freeze in the bottle, causing it to explode.

Large bucket

Ice

Rock salt

Thermometer

Experiment

This experiment requires a lot of trial and error to figure out exactly to get the conditions exactly right as there are a lot of factors involved. The measurements of ice, water, and rock salt that are suggested might vary because of environmental factors. With that in mind the experiment follows these steps (Wells, 2013):

1. Start by filling the bucket or container 3/4-full with ice.

2. Place the water bottle in the bowl of ice.

3. Add a generous amount of rock salt to the bowl.

4. Place the thermometer in the ice mixture and watch the thermometer closely.

5. Wait until the temperature of bowl drops to -8°C. If the soda gets any colder, the liquid will freeze prematurely. Depending on the temperature of the mixture, you might need to add more ice or add more salt.

6. Once the soda (water) has been at the appropriate temperature for 10 minutes, gently remove the bottle from the ice-salt mixture and strike it against the table. Ice crystals should immediately form at the top of the bottle and quickly make their way down through the bottle, creating an instant freeze.

7. As a second experiment, remove another bottle from the ice bath and carefully open it. What happens?

Explanation

Everyone knows that water freezes at 0 °C - or does it? When water freezes, it needs a nucleus in order for the solid crystals to form and become ice and water is typically full of particles and impurities which have no problem kicking off the crystallization process; however, purified water by definition doesn't have those impurities and with nothing for the water molecules to latch onto, purified water can be supercooled as far as -40°C (Winter, 2014). Once the solution is supercooled, then the solution is simply waiting for something to allow it to begin freezing. Opening the bottle allows carbon dioxide bubbles to form and these bubbles provide a place for the nucleation of the ice crystals to begin occurring (Poulter, N.d.).

Liquid water is a network of water molecules (each with two hydrogen atoms and one oxygen atom) held loosely together by what is called hydrogen bonding, which is somewhat like static cling and depending on its temperature and pressure, water ice has 16 different crystalline forms in which water molecules cling to each other with hydrogen bonds (University of Utah, 2011). Researchers explain that "what makes water so strange is that the way liquid water behaves is completely different from other liquids. For example, ice floats on water while most solids sink into their liquid forms because they are denser than the liquids (University of Utah, 2011)." However, one of the most interesting facts about water is alter its freezing point by preventing it from forming the first seed of ice.