# Time-Temp relationship with water/ice phase-change

• Ed Boon
In summary, the time and temperature relationship during the phase change of water/ice is directly proportional, with the melting point and freezing point of water being affected by altitude and impurities in the water. Additionally, the container in which the water/ice is placed can also affect the rate of the phase change.
Ed Boon
I am a college student working on a project, I was wondering if someone might share some info about the subject in the title. We are working with a freeze thaw cabinet and I am looking for equations/info on how much time the phase change will take at different surrounding temperatures for different ammounts of ice. Again, any information is appriciated, I am a EE and it has been a while since my calc-physics classes.
Thanks

any equations would help

I am happy to share some information about the time-temperature relationship with water/ice phase-change. This is a well-studied phenomenon and there are some equations that can help predict the time it takes for water to change phases from ice to liquid or vice versa.

The equation that describes this relationship is known as the Stefan equation, which states that the rate of phase change is directly proportional to the temperature difference between the surrounding environment and the melting/freezing point of the substance. In this case, the substance is water and its melting/freezing point is 0°C (32°F).

The rate of phase change can also be affected by the amount of ice present. This is because a larger amount of ice will take longer to melt compared to a smaller amount. This relationship can be described by the principle of latent heat, which states that a certain amount of heat is required to change the phase of a substance without changing its temperature.

In order to determine the time it will take for water to change phases in your freeze-thaw cabinet, you will need to know the initial temperature of the water/ice mixture, the temperature of the surrounding environment, and the amount of ice present. With this information, you can use the Stefan equation and the principle of latent heat to calculate the time it will take for the phase change to occur.

I hope this information helps with your project. Keep in mind that there may be other factors that can affect the time-temperature relationship, such as the shape and size of the ice, the type of container it is in, and any external factors like air flow or pressure. It may be helpful to consult with a physics or thermodynamics expert for a more detailed analysis. Good luck with your project!

## What is the relationship between time and temperature during the phase change of water/ice?

The time and temperature relationship during the phase change of water/ice is directly proportional. This means that as the temperature increases, the time it takes for water to change from a solid to a liquid state (melting) or from a liquid to a solid state (freezing) decreases. This relationship is known as the melting point and freezing point of water.

## Why does water take longer to melt than to freeze?

Water takes longer to melt than to freeze because melting requires more energy than freezing. In order for solid ice to melt into liquid water, energy must be absorbed in the form of heat. On the other hand, when liquid water freezes into solid ice, energy is released in the form of heat. This means that it takes longer for water to reach its melting point than its freezing point.

## Does the altitude affect the time-temperature relationship for water/ice phase change?

Yes, altitude does affect the time-temperature relationship for water/ice phase change. As altitude increases, the air pressure decreases, which in turn affects the boiling and melting points of water. This means that at higher altitudes, water will boil and freeze at lower temperatures, leading to a longer time for the phase change to occur.

## Can the time-temperature relationship for water/ice phase change be affected by impurities in the water?

Yes, impurities in water can affect the time-temperature relationship for phase change. Impurities such as salt, sugar, or other substances can lower the freezing point of water, making it take longer to freeze. This is because the impurities disrupt the crystal structure of ice and prevent it from forming at its normal freezing point.

## Is the time-temperature relationship for water/ice phase change affected by the container it is in?

Yes, the container can affect the time-temperature relationship for water/ice phase change. The material and thickness of the container can impact the rate at which heat is transferred to or from the water/ice. A thicker container will insulate the water/ice and slow down the phase change, while a thinner container will allow for quicker heat transfer and a faster phase change.

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