Step 1: The Materials!
-thermometer (good range would be -10°C to 110°C)
-transparent plastic cups (tip: a tall, narrow shape works best)
-piece of cardboard (e.g., empty cereal box)
Step 2: Steps 1 , 2, and 3!
Cut a circle from the cereal box to use as a cover for the plastic cup.
Pour a small sample of distilled water into a clean plastic cup and place the cup in the center of the bowl.
Cover the cup with the cardboard, then add ice cubes to the bowl, so that the ice is above the level of water in the cup. Be careful not to get any ice inside the cup.
Step 3: Steps 4, 5, and 6!
Sprinkle two tablespoons of salt over the ice cubes. Be careful not to get any salt inside the cup.
Uncover the cup and put the thermometer inside.
Monitor the temperature of the water. Over the next 10–20 minutes or so, you should see the temperature slowly decrease. Keep track of the time and temperature in your lab notebook.
Step 4: Step 7, and 8!(The Last Steps Until It Looks Like That!)
When the temperature of the water reaches −1 to −3 deg;C or so, carefully remove the cup from the ice bath.
Repeat the procedure, testing different types of water to see whether it can be supercooled before freezing. For each type of water, run at least three trials (more is better). Here are some ideas for types of water to test:
bottled distilled water,
bottled spring water,
plain tap water,
any of the above that have been boiled and then allowed to cool to room temperature.