HEAT CHEAT SHEET
What is
heat?
Heat is the amount of energy flowing from one body (solid,
liquid or gas) to another body spontaneously due to their temperature
difference. Heat always moves from high
concentrations to low concentrations. In
this sense, heat is always lost from one source, and given to another. On this point, it is important to recognise
that nothing gains cold. Rather you lose heat or gain heat.
Newton's Law of
Cooling
Newton's Law of Cooling states that the rate of change of
the temperature of an object is proportional to the difference between its own
temperature and the temperature of its surroundings. This means, the larger difference between an
object’s temperature and its environments, the faster its temperature
drops.
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| Taken from http://ctcp.massey.ac.nz/lein/lectures/124.102-Unit-02-Lecture-4.pdf |
When you added milk you dropped the temperature of your cup of tea. We know that the hotter something is, the faster the temperature will drop. At some point, the temperature stops being super hot, so it begins to cool more slowly.
Does adding the milk at the start drop the temperature enough to slow the rate of cooling?
Between 7G and 7R most people found little to no difference between the final temperature whether the milk was added at the start, or at the end.
Using both the graphs that you see, your data, and perhaps another quick experiment, can you tell me why it makes no difference?
Questions:
On a separate piece of paper
or computer: Create a graph your results
- 1. What did you find in your experiment? When is
the optimum time to add milk to have a hot cup of tea? Make sure you refer directly and specifically
back to your data.
-
2. 2. Read the ‘HEAT CHEAT SHEET’ above. Use this to speculate some reasons about why
you received the results you did (or that the group did).
- 3. Where your results similar to those around you?
Why might some people get different results?
-
- 4. How would you improve your experiment for next
time?
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