Science Project on the Freezing Rate of Different Types of Water

Water does not always freeze at the same temperature.

Using water to demonstrate the different states of matter is a very common classroom experiment because it can be easily demonstrated using a freezer and a kettle. What is not always explained is how adding other elements to water, for example salt, can radically affect the freezing point. Use this concept to create a good science project with some practical applications.

Freezing Different Water Types

Collect a range of water samples. These should include tap water, bottled water, salt water and sugar water. Freeze all of the samples and time how long it takes each of them to go from a liquid state at room temperature to a solid state. Take regular temperature readings to see how cold the samples have to be to turn from a liquid to a solid.

Defrosting Different Water Types

Once all of the samples are frozen and you have collected all of the time and temperature data, take the samples out of the freezer and leave them at room temperature. Take the same readings as before to find out if the results are the same when the samples go from a solid state back to a liquid.

Real World Application

One of the most obvious applications for this idea in the real world is in road gritting, where salt is used on roads during the winter to prevent a layer of ice from forming on the top. Use a variety of substances on a model of a road to see which substance is the best at stopping the ice from forming.

Volume Changes

As ordinary water freezes it expands. This is why a glass of water will break if you put it in the freezer. Freeze different types of water in plastic measuring containers (containers with measurements up the sides) to determine if this is true of all water types.

References

• Kids Science Experiments: Freezing Water
• Lesson Plans Page: Changing the Freezing Point of Water With Salt