Physics/chemistry behind the observation
This is purely observation based. Any time I have cooking something on the stove, if I change intensity in any direction - reducing or increasing the heat, it seems like water vapor threads shoot out from the pot.
I can understand if I increase the heat, more energy, but don't have any explanation for reducing the heat. It seems like state change any direction causes some water vapor to release.
Don't think it matters, but it's gas based stove.
What causes the vapor or threads of mist to shootout when there is a change ?
Best Answer
It's hard to say without seeing it, but I suggest that this phenomenon happening when you turn up or down the gas may be caused by your arm reaching out in the vicinity of the pot to turn the knob.
The air above the pot should be saturated with water vapor at a higher temperature. Motion nearby will create eddy currents that carry that moist air to where it can meet cooler air. You see the moisture when it condenses to fog.
Pictures about "Physics/chemistry behind the observation"
How do you explain observation in chemistry?
Using Observations to Gather Evidence In some chemical changes, for example, a substance turns from one color to another. You can see an example of this in the Figure below. In other chemical changes, an odor is produced or gas bubbles are released. All of these changes can be observed with the senses.How is observation connected to chemistry?
Using Observations to Gather Evidence They help scientists gather evidence. For example, to investigate whether a chemical change has occurred, a scientist might observe whether certain telltale signs are present. In some chemical changes, for example, a substance turns from one color to another.What is an observation in physics?
In physics, the observer effect is the disturbance of an observed system by the act of observation. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner.Why is observation important in chemistry?
Observation is essential in science. Scientists use observation to collect and record data, which enables them to construct and then test hypotheses and theories.ASTROCHEMISTRY: THE OBSERVATIONS OF MOLECULES AND SOLIDS IN SPACE
More answers regarding physics/chemistry behind the observation
Answer 2
I don't know about turning the heat up and your observation, but seeing more "steam" when turning the heat down or off is often wondered about. It was asked and answered on the physics stack exchange. Basically, since "steam" is transparent water vapor, what you are seeing when the cooling happens is a cloud of condensed water vapor. The issue with the observation and answering the questions lies in the difference between true steam and this condensate. There is more information in the link. What you are seeing when you turn the heat off (or down) is the condensation of the water vapor, which obviously happens at a lower temperature than that needed to keep the water vapor transparent (at least most of it...which is way you always see a little of the condensate).
By the way, it looks like there is a duplicate question in physics, as pointed out in the comments above.
Answer 3
I think what you're observing has a common name in the culinary world. It's called carry-over heat. Assuming you have a big pot on the stove, and the heat source is at the bottom. The bottom of the pot is hotter than the top of the pot; say there's a 5C difference. Bottom is 99C, top is 94C (almost boiling)
Even when you turn off the heat, the heat from the bottom portion of the liquid will continue heating the top portion to an equilibrium between 94 and 99. Say 96; and 96 is already good enough to observe steam on the top.
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Mikhail Nilov, Mikhail Nilov, Mikhail Nilov, Mikhail Nilov