How come ducks don't get cold feet in freezing water?
94711
The real answer is that waterbirds have a really clever method of stoping the cold blood from their feet mixing with the blood from their bodies, and vice versa. \n\nAs blood flows into the feet it passes right beside the blood flowing out. Most of  the heat is drawn from the warm blood before it reaches the feet, but enough heat remains to prevent the feet from freezing.  \n\nThe blood then leaves the feet, passing close to fresh blood coming in. The cold blood draws the heat form the warm blood, and thus warms up before it enters the body again.  That prevents the duck form getting cold even though its feet are just a few degrees above freezing.\n\nThis system is most well developed in the penguins, some of which spend months at a time standing on ice.  If the solution was simply that the feet contained no nerves or blood vessels the penguins may not feel cold,  but there feet would freeze solid and shatter into a million pieces as soon as they tried to move them.\n\n_____________________________\n>>>>Ducks' feet have no nerves or blood vessels. \n\nThis is just nonsense of course. If a ducks feet have no blood vessels then how exactly do you think they supply oxygen to the cells?
346699
Yes. Penguins appear to have very short legs and no knees because only the lower leg is externally visible. Their knees and upper legs are feather covered, hiding them from view. This also means that penguins never get cold knees\nSee\nhttp://www.penguin.net.nz/faq/faq.html
292689
On extremely cold days many birds will roost to conserve heat. If they take to the air they expose their underwings and bodies, and the short insulating feathers under the flight feathers are exposed to the cold air, so they no longer provide adequate insulation.
361002
The convection of heat in the water carries warm water from the bottom of the water, nearest the warm earth, to the surface and back.\nThis motion maintains enough warmth throughout the water to prevent the fish from freezing.  The bodies of the fish also enables them to survive in near freezing temperatures by moving constantly.\nConvection always occurs, in Summer and Winter.  And the pattern never changes.
80785
One thing I know, salt reduces the freezing temperature of water, its why ppl use salt on snow and ice. Not because it melts it, but because it reduces the freezing temp.
313475
The primary reason water expands upon freezing is the breakage of hydrogen bonds.  The hydrogen bonding which occurs in the polar water molecules acts to bind water molecules closer together than they would otherwise.  When freezing, though, those hydrogen bonds must break in favor of the crystalline solid structure (which packs the molecules less densely).  Hydrogen bonding also leads to the extremely high boiling point of water for such a small molecule (most molecules of small molecular weight are gases at much lower temperatures than 100 deg C).\n\nIn fact, hydrogen bonding contributes to just about every unusual property of water.  There are very few molecules in nature that exhibit hydrogen bonding; and none, to my knowledge, exhibit it as strongly as water.  Alcohols have some hydrogen bonding, which is why they have higher boiling points than other, comparable molecular weight organics.
914326
Penguins have great protection from the freezing conditions, which by the way they happily endure. Afterall, they know no different. Depending on the species of penguin, some have a very fine plumage which traps a layer of air. This protects them from the cold, other species have a very thick layer of skin almost like rubber. Great protection !
473979
Some of these answers are close but the truth is, the water doesn't have to be freezing cold to cause hypothermia.  The wetsuit will allow a thin layer of water to come in between your skin and the suit, which is then warmed to near body temperature.  That way, you are able to stay in the water longer without your body heat transfering out into the water.  Without the suit, even in relatively mild water, you constantly lose body heat (unless the water is over 90 degrees farenheit) and after a few minutes you can begin to get uncontrollable shivering/shaking, and if you stay too long, hypothermia can set in (which can be fatal).
925921
like what do you mean,like why can you swim in cold weather? because the water is a higher temperature then outside...im learning this right now in science,but i dont listen alot...lol..sorry
1002192
Depends. Downpours and flooding will make even a water loving duck look for somewhere to get a break from the deluge.\n\nI own a couple of ducks, and if it's raining hard, they hunker down or even hide under their shed. A light drizzle they like especially since it makes the dirt yummy and they look for worms.\n\nDucks have oily feathers (special duck oil) that causes water to roll off their backs so they don't get wet and cold.  They also have a lot of body fat which keeps them warm, so wet doesn't bother them.
663824
it lowers the freezing point of water, make it more dense, so it has to e colder for water to freeze
555489
Water is a liquid and until the water get near freezing, water as it cools becomes more dense and sinks. Warmer water moves to the surface. For ice to form on a lake the temperate of all the water in the lake has to get below 39 degree F. \n\nLand on the surface may get colder but in temperate climates at certain depth the soil is always above freezing.
247169
Cold. Their water evaporates slower.
96783
The water itself isn’t any hotter or colder, it’s exactly the same temperature. It just feels hotter or colder because air is cooler or warmer.\nThe ground has a very stable temperature, and more than a few feet under in most places and the temperature varies by just a couple of degrees all year round. That’s; why wine and vegetables are commonly store din cellars, to protect them from the heat and cold. Water in the ground has an equally stable temperature.\n\nSo in summer the water is going to be several degree cooler than the air, and so it will feel cold. In winter despite being the same actual temperature it will be several degrees warmer than the air, and will fel warm.
823520
Yes. Penguins appear to have very short legs and no knees because only the lower leg is externally visible. Their knees and upper legs are feather covered, hiding them from view. This also means that penguins never get cold knees!...;
237724
Infact, FLOWING water does freeze. but FLOWING WATER cannot freeze completely at 32 degrees providing it is attinaing warmth from somewhaere else. If you check the temp of a glass of ice water. It is 32 degrees but it is not completely frozen! 32 degrees is when ice begins to form &/or can sustain itself. The only reason your ice melts is because the water temp surrounding the ice is conducting the heat of the room which in turn tries to rise the water temp. While the ice is trying to hold the temp @ 32 degrees. Eventually the ice will melt; it releases cold in the form of water, to cool the water surrounding it. But because the warmth of the room is indefinate, the ice will eventually melt away as it is unable to hold the temp. Now if you put you ice water in a freezer that's set at 32 degrees. Your water will freeze. Because the water is no longer drawing the energy it needs to sustain its heat so the ice wins and freezes the water. \nSo how the heck does this pertain to rivers and moving water?\nMoving water is gaining warmth from the ground and the air. but becaue its moveing the temp of 32 degrees is not easily sustained so the ice melts and refreezes as it travels, because the weather changes and temps change ect. The only way to freeze moving water it to either:\n1. Have it be so cold that the water nearly immidiatly freezes (well below zero) or \n2. Have a sustained temp of below 32 for several hundreds of miles. \nNow if you put the water in a water rocker and put it in the fridge at 32 degrees it will freeze solid at some point because the temp is sustained and really how long it takes for it to freeze is the ultimate question. which depends entirely on the temp.\n-hope that helps
925346
It's a mixture of the above answers: the penguin does control the flow of blood to the feet, by varying the diameter of the vessels carrying blood into the feet. When it is cold they reduce the flow (this means less blood to heat up when on its way back into the body). The second method of control is by way of the countercurrent heat exchangers at the top of the penguin's legs. The blood vessels break into many smaller vessels that are very close to similar small vessels coming back up into the body. All the heat flows from the warm blood into the cold, meaning little warmth is carried down into the feet and lost to the environment, keeping the heat in the penguin! The feet are a degree or two above freezing, which is just above what they would get frostbite at, but still minimises heat loss.