While my friend was making a nice cup of British tea today, I noticed that when he put cold milk into the tea, it first sank but then almost immediately afterwards floated upwards. He thought it could be that the cold milk warmed up and hence floated to the top since warmer liquids are less dense. Is that the only reason or are there others?
mgb_phys
Jul4-08, 09:01 PM
He added milk to tea ..... shakes head .....
DaveC426913
Jul4-08, 09:52 PM
He thought it could be that the cold milk warmed up and hence floated to the top since warmer liquids are less dense.Well, the milk didn't get warmer than the tea it was sitting in, now did it?
1] Fat floats in water.
2] Pouring a liquid into another liquids will tend to set up a circulatory system. bringing the milk back up top.
Borek
Jul5-08, 02:57 AM
I am with Dave's 2 - I would bet mainly on circulation. Milk density is slightly higher than that of water, but not enough to stay on the bottom. Most likely any other liquid with density and viscosity similar to that of water will behave exactly the same way, milk is just easier to see.
madmike159
Jul5-08, 03:21 AM
He added milk to tea ..... shakes head .....
You have milk with out tea:confused: Why?
Danger
Jul5-08, 04:22 AM
He added milk to tea ..... shakes head .....
Echo that. :yuck: :yuck: :yuck:
madmike159
Jul5-08, 04:24 AM
You have milk with out tea:confused: Why?
Woops I ment tea with out milk lol. disgusting:yuck:
Andy Resnick
Jul6-08, 08:57 PM
While my friend was making a nice cup of British tea today, I noticed that when he put cold milk into the tea, it first sank but then almost immediately afterwards floated upwards. He thought it could be that the cold milk warmed up and hence floated to the top since warmer liquids are less dense. Is that the only reason or are there others?
I'm sure part of the answer is becasue he *poured* it in, rather than floated it on (i.e. black and tans, pousse-cafe drinks, etc.). Then, because milk and tea are miscible, mixing ocurred along with whater convective-inertial flow ocurred.