Does turning a spoon in water raises the temperature?

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SUMMARY

The discussion centers on the misconception that stirring a spoon in water does not raise the temperature of the water, contrasting it with Joule's experiment on mechanical work and heat transformation. Key points include the necessity of accurate temperature measurement and the importance of insulation to prevent heat loss. Participants emphasize that energy input from stirring may not be sufficient to produce a measurable temperature change without proper experimental controls. Additionally, the differences between Joule's controlled apparatus and a simple bowl and spoon setup are highlighted.

PREREQUISITES
  • Understanding of Joule's experiment and the mechanical work-heat transformation principle
  • Knowledge of thermodynamics, specifically conservation of energy
  • Familiarity with temperature measurement techniques and accuracy
  • Basic principles of heat transfer, including conduction and insulation
NEXT STEPS
  • Explore the principles of thermodynamics and energy conservation in detail
  • Learn about accurate temperature measurement techniques and the specifications of thermometers
  • Investigate the effects of insulation on heat retention in experimental setups
  • Study the differences between controlled experiments and everyday scenarios in physics
USEFUL FOR

Students studying physics, educators teaching thermodynamics, and anyone interested in experimental physics and heat transfer principles.

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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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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