# A baffling physics question

by FatFreek 2005 25 Replies latest social current

• ##### stan livedeath

The real physics question is how much weight will you gain over the next few weeks!

• ##### smiddy

Their is also the plus -minus error % to be considered with each recording.,are they outside these limits or within these limits.?

Their is always a margin of error to be taken in consideration with any experiment either with the same person doing the experiment and a different margin with someone else doing the same experiment..

• ##### waton

and remember, free hot air is always less buoyant than the the cool.

• ##### cofty

Water lost as steam.

• ##### aintenoughwiskey

Heat from the cup could be altering the scale. Try with an insulator between cup and scale.

• ##### joey jojo

Agree with Scully.

Has to be some loss on the spoon because you stir each time, plus a little in evaporation.

• ##### eyeuse2badub

I think that your scale may have "overlapping" numbers that sometimes get confused. If all else fails 'wait on jehober'. Final answer!

just saying!

• ##### Island Man

It's not a 10% reduction in weight. The whole thing originally weighed a 16oz then you added in the 30g of syrup. so that's a little more than 17oz. So when it drops from 30g to 26g that's not reflective of a 10% drop in mass because the scale was set to show only the difference over 16oz, remember? So the difference is actually much less than 10% - something like a little over 0.5%. I find this very believable and easily attributable to evaporation of some of the liquid owing to the heating in the microwave and exacerbated by the agitation of the hot liquid due to stirring.

• ##### Nathan Natas

One teaspoon of water is about 5 grams (5ml), so between evaporation and what sticks to the spoon you may have the answer you seek.

On the other hand, some of your beverage may be converting to rich, chocolate-y "DARK MATTER."

Physics is yummy.

• ##### Anony Mous

Boiling 'water' loses about 6%/hour to evaporation so over the 5 minutes you make your 'hot chocolate', you may lose ~0.5% (you have to measure both masses and time and add error bars). Given your ~500g of total 'mass' (16 "oz" + 30 g - please keep the units consistent next time) , losing 0.5% would be ~2.5g - right in line with your measurement (again, add error bars of 0.5-1g depending on your scale).

Additionally adding cold liquid to hot liquids causes turbulence/circulation which may cause hot pockets on the bottom to rise faster and evaporate faster. If you stir, you make it worse.

Also E=mc^2 so as you lose heat (energy), you lose mass although your scale isn't near precise enough to give you an exact number.

You need much more precise measurements to give you exact numbers, if you write a paper though, you may be in line for an Ig Nobel.