Does turning a spoon in water raises the temperature?

In summary, the conversation discusses Joule's experiment on the transformation of mechanical work into heat and how it relates to a person's own experiment of stirring water with a spoon. It raises questions about the accuracy of measuring temperature changes, insulation, and other factors that could affect the results. The conversation also highlights the differences between Joule's apparatus and the bowl and spoon experiment.
  • #1
godingly
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Homework Statement


I read about Joule's experiment proving the transformation of mechanical work into heat. But say I have a bowl with some water, and I start turning a spoon in it very fast, thus doing work - the water won't get hotter! What am I missing?

Homework Equations


conservation of energy

The Attempt at a Solution


I think maybe the work will simply go to movement and not to heat, but then how do you explain Joule's experiment?
 
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  • #2
How did you determine that your stirred water didn't get hotter? Did you measure the temperature of the water in your bowl with a sufficiently accurate thermometer? What is "sufficient"? How much heat would you have to put into the water in order for you to see a measurable change in the temperature? What's your estimate of the energy you put into the water by stirring? Was the bowl sufficiently insulated to prevent heat escaping before you could see its effects? Did you characterize all the ways heat could move from the bowl to its surroundings? How about heat conducted by the spoon to or from your hand?

In what ways does Joule's apparatus differ from your bowl & spoon experiment? What steps did Joule take to minimize or damp bulk motion of the water? Did you do the same?
 
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1. What is the scientific explanation behind turning a spoon in water raising the temperature?

When you turn a spoon in water, you are increasing the kinetic energy of the water molecules. This causes them to collide with each other more frequently, resulting in an increase in temperature.

2. Is there a specific type of spoon that works best for raising the temperature of water?

No, the type of spoon does not significantly impact the temperature of the water. Any spoon that is able to stir the water will result in a temperature increase.

3. Can turning a spoon in water raise the temperature significantly?

It depends on the initial temperature of the water and the length of time the spoon is turned. In most cases, the temperature increase will be minimal.

4. Are there any other factors that can impact the temperature of water when a spoon is turned in it?

Yes, the size and shape of the spoon, as well as the volume of water, can also play a role in the temperature increase. Additionally, the speed and force with which the spoon is turned can also affect the temperature change.

5. Why does turning a spoon in water not always raise the temperature?

Turning a spoon in water can only increase the temperature if there is enough kinetic energy being transferred to the water molecules. If the spoon is turned too slowly or the water is already at a high temperature, the temperature change may not be noticeable.

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