Why does a boiling pot of water shake?
The metal on the bottom of the bowl, whether flat or curved, is smaller before heating than during heating. As you begin to heat the metal the metal expands radially and the circumference area of the bowl has more material than the center. So the outside of the circle area expands at a different rate than the center. The expanding metal has to go somewhere so it ripples and distorts the whole bowl while the metal is finding someplace to reside with it's temporary larger dimensions. You can see this with a flat steel circular saw blade. If you put it on a burner the flat round disk will curve up into a dish shape as the metal on the rim expands and the metal in the center pushes out also. Sometimes the metal just rips. In a steel pan it is made to handle the expansion by shaping the edge of the pan with sloping upward metal. So the Steel or Aluminum just creeps around the curve while it expands. The water in the pan limits the rise in temperature of the steel to 212F but any rise in temperature causes metals to expand and that expansion has to go somewhere. Similarly, when it cools down, the metal shrinks back to the original location. But this is what makes the noise and movement, the expansion and contraction of a round shaped object expanding at different rates around the circle Also water is different than say cooking fried chicken. In cooking oil the pan expands during the heating and pretty much stays at temperature. But in boiling water you have extreme convection currents. The pan directly in contact with the burner might reach 600F as it transfers its heat to the water. But then it forms vapor bubbles at the bottom that insulates the bottom of the pan from the rest of the water.This makes the temperature of the pan spike up more until the bubble leaves the bottom of the pan as a steam bubble. Immediately cool water replaces the void left by the rising bubble and shock cools the spot back to 212F. This water being so fluid, moves heat around the pan very rapidly so that the pan bottom experiences point temperature hotspots of 800F or so and other spots at 212F and constantly in motion. That is why it is so noisy cooking water having all of those expansions and contractions in thousands of point locations all along the round bottom. Ever throw cold water on a hot pan surface and here that shriek sound? That is rapid contraction from a high expansion
If cold water is filled in the pot, heat transfer takes place from low temperature to high temperature. Is this violating the second law of thermodynamics?
Actually it's still from high temperature to low temperature. Take this in chunksWater inside the pot exerts pressure on the walls of the pot.Due to the pressure the water seeps into the pores in the pot (presuming the pot is earthen/ceramic)Water reaches the outer surface of the pot and gets in contact with the air flowing across the pot.As the air flowing around the pot is not fully moisture saturated (Humid), it absorbs some of the water from the surface of the pot and carries it away in the form of water vaporThe water which just got evaporated, carried away the heat of the earthen pot thus making it cooler than the water inside the potThe temperature of the pot and the water inside is now different and will try to equalize by water giving out its heat back to the pots surface LOOSING TEMPERATURE.The cycle will repeat indefinitely till there is water inside the pot and the outside air is not too humidSo as in every step, energy is flowing from higher side of the gradient to the lower side HENCE ABIDING BY THE RULES OF THE SECOND LAW OF THERMODYNAMICS.Also if you fill cold water inside the pot, the evaporation will cause the water to maintain its temperature.I hope I was able to answer your question adequately.
If I leave a pot of boiling water on all day, will it cause a fire?
Most likely...yes. I wouldn't take any chances... Call a neighbor or the local fire dept. Let them know. Maybe someone you know can go in and turn it off. It's not worth the risk of losing everything you have to take a chance on it NOT burning down the house.
Does covering a pot of water when heating it on the stove make it boil faster?
The various answers do largely address relevant factors that determine the speed of boiling water in a pan. For a pan lid that floats and rattles about on the boiling water, the elevation of pressure will be insignificant in terms of raising the boiling point of water.The single most important factor, hardly touched upon among several of the answers, is the effect of the lid on condensing the hot, saturated vapour and draining it back into the water being heated. The amount of latent heat in water vapour is extremely large (540 cal/gm) and, if the latter is condensed back into the water, would make a significant difference to the time taken for the water to reach bp.Indeed , it is common experience that when the lid is hopping about on the top edge of the pan due to steam pressure at the boiling temperature, it is necessary to reduce the heat input substantially in order to prevent over-boiling in contrast with maintaining boiling conditions for an open pan. The reason? - condensation of steam back into the water. The heat-recovery effect of vapour condensation at lower temperatures reduces the time required to boil the water over that without a lid.The principle of recovering latent heat from the products of combustion is exploited in gas-fired condensation boilers.
What will happen to the water inside the pot when it is heated?
It absorbs heat.Volume and temperature increases,.When it reaches 100 deg C it start boiling.water changes to steam rapidly.Initial stage hot water goes up and cold water comes down due to Convection
What does it mean when you boil eggs and one is floating and the rest are sitting on the bottom of the pot?
LOL...that sounds like a bad egg....that has ever happened to me, I wouldn't even chance opening it to check
My flower pots are full of ants kept in my back lawn. What do I do to make them leave my pots?
I’m not sure they pose any threat to your plants, unless they’re farming aphids on the leaves and stems.If, however, you find it necessary to get rid of the ants, don’t use poisons, just use water. Assuming there are drainage holes in the pots, set the pots in a tub full of water so that the water is as high as the soil level in the pot. Add water to the tub to keep water just below the rim of the pot. Plant roots can survive without oxygen for much longer than ants can. After the soil in the pots appears to be saturated, allow them to remain in the water for another 30 to 60 minutes. Because it’s the only refuge, it’s likely that the ants that escape the soil will climb up onto the plant. Hose them off with a spray of water. Remove the pots from the tubs and allow them drain.
Similac baby formula ~ Do I mix with warm water? please read full details below?
If you have bought the concentrated formula then it's ok to use the pre boiled water. But once the can is opened the remainder must be refrigerated. Once you mix then next bottle it maybe a bit too cold, so yes warm up the bottle. I make up the full can at once, so I have several bottles in the fridge at once. I bought a good bottle warmer, it only takes seconds to warm. The warmer is by first years. I had to add this after reading a few of the other posting. You CAN'T use warm tap water for babies under 6 months, the must be boiled for at least 2 mins. Just like their bottles, they have to be sterilized by having them in boiling water for at least 2 minutes or in a sterilizing unit. As I'm making alot of bottles, I invested in a good sterilzer.