Why does a swimming pool at 25 degrees have more thermal energy than a cup of tea at 80 degrees?

Question

i thought a cup of tea would have more because it has a higher temperature...but the answer is the swimming pool at 25 degrees

Please explain why.. thanks !

Answer 1

Both have thermal energy. The cup has more energy per unit of volume, but it has much, much less volume.

Think about it using this analogy. Think of the cup of tea as a bank account with 80 'thermal' dollars in it. The pool has (just as a rough guess) the volume of 10,000 cups of tea. So, using our analogy, the pool has 10,000 bank accounts - each worth 25 'thermal' dollars.

Which would you rather own? One bank account (the 'cup of tea' account) worth 80 dollars, or 10,000 bank accounts (the 'pool accounts'), each worth only 25 dollars?

Hope this helps. Best wishes and good luck.

Answer 2

Convert them to both to kelvin (an absolute temperature scale).

25C + 273.15 = 298.15K

80C + 273.15 = 353.15K

So you've got a swimming pool at 298.15K and a cup of tea at 353.15K. Not a big difference when you're talking about the absolute value of molecular kinetic energy.

That means that if the pool is 10,000 times the size of the cup of tea, then it has about 8,443 times the amount of thermal energy.

Answer 3

Let us say that your cup of tea is 200grams.
Also say it has gone cold to say, 15°C.
To warm it up again to 80°C. As in you're question.
This will be...
200g x 4.184J/g/°C x 65°C (Temp Increase).
= 200 x 4.184 x 80 = 66,944 Joules of heat energy added to bring the tea to 80°C.

Now, the swimming pool, starting at 15°C and you're to heat it to 25°C...as in the question...
Let us say the pool contains 20 million grams of water. (20,000 litres).
Then...20,000,000g x 4.184J/g/°C x 10°C (Temp. Increase).
= 20,000,000 x 4.184 x 10 = 836,800,000 Joules of heat energy added to bring the pool to 25°C....
The tea is much hotter than the pool but, look at the heat energy added to each....which do you think contains the most heat energy ?
I hope you understood all that....Good luck, I'm ready to help anytime...

Answer 4

cant swim in a cup of tea the spoon would get in the way

Answer 5

Because there is more volume to try and keep at the same temerature.

Answer 6

Because there's so much more of it, (volume * temperature).