When you have food that is hot out of the oven, does blowing on it really significantly decrease the time it takes to cool it down to a temperature that is edible? In other words if you had a fork full of hot lasagna that you just held up with one hand, and another fork that you blew on, would the temperature of the blown on food be a lot different after 60-90 seconds?
2006-07-26 07:08:34 · 13 answers · asked by lawndrnot 2 in Science & Mathematics ➔ Physics
Yes! Thermodynamics says so. The air by the food is colder than the food, allowing the heat to dissipate into the air. However, if that air is stationary, there will be a local environment around the food item of warmer air - basically meaning that less heat will be transfered. If you blow air on your food, you're disrupting this pocket of warm air, allowing the food to have constant contact with 'colder' air. This will wick away the heat faster.
Another proof of this is trying to cool down objects with warm air vs. cold air (say, if the room temperature is higher, or using a blow dryer). The warmer the air, the slower the food item will get colder.
Although your food would be much cooler if you ran it under cold water, but...
2006-07-26 07:15:47 · answer #1 · answered by michelsa0276 4 · 1⤊ 0⤋
In the sense that heat in the food is transferred to the surrounding air, the ciruculation of air across the surface area of the food would tend to increase the rate of cooling, yes. How significant this would be would depend on the volume of air circulated across the surface area of the food, the ambient temperature of the air that was circulated, and the temperature of the food itself. There would most likely be a measurable difference in the temperature of the food, although depending on the size of the piece of lasagna and its ability to retain heat within its core, there might be less variation in the temperature at the 'center' of each of the respective pieces. You could always try an experiment with two meat thermometers stuck into the center of the two pieces of lasagna.
2006-07-26 07:16:03 · answer #2 · answered by zzzzzzzzzzzzzzzzzz 4 · 0⤊ 0⤋
Yes. Here's why: Heat is always rising up from the food and warming the air around it. By blowing, you move the heated air molecules (or even vapor/steam for food with high water content like soups) away from the food. This allows the heat to escape from the food faster.
If you want to speed the process, stirring and blowing together work best. Of course, you can risk getting spit on your food so that's the drawback. 90 seconds will make a difference but probably something like 30 seconds won't.
2006-07-26 07:14:03 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Yes, in the same ways that you get colder on a windy winter day than on a calm day of the same temperature.
The reason is that the warm food will warm the air around it. Since stagnant air is a pretty poor conductor of heat, the layer of warm air around the food will keep it warm. If you blow away that hot layer of air, it is replaced by cooler air, which will now absorb heat from the food. Keep blowing, and your food will always have a supply of fresh, cool air sucking away the heat.
Back to the cold day analogy, this is also related to why we wear thick clothes when it is cold. The clothes help keep the boundary layer of warm air surrounding our body from being blown away by the wind.
2006-07-26 09:13:54 · answer #4 · answered by mch 1 · 0⤊ 0⤋
Unless your breath is impossibly hot, blowing on food will increase the rate of cooling due to convection of food-heat into the surrounding air. Blowing on food does make it cool off faster, but depending on the starting temperature (hotter starting temperature will give you more dramatic results due to greater differential), you may not see anything significant after 60 seconds, it may take longer.
2006-07-26 08:35:24 · answer #5 · answered by 138+ 2 · 0⤊ 0⤋
Yes small amounts of blown food will cool off quicker than non blown food.
With blown food:you are pushing cold surrounding air to it, the hot air moves away from food in the process carrying heat with thereby cooling the food.
Same process happens to the non blown food only it takes longer to cool off.
2006-07-26 07:46:29 · answer #6 · answered by mamanoelia 3 · 0⤊ 0⤋
yes. the lasagna prob comes out about 250-300 degrees. so blowing on it with 98 degree breath will cool it faster than no airflow going over it.
2006-07-26 07:11:55 · answer #7 · answered by chrodo 2 · 0⤊ 0⤋
Try your own experiment:
All things being equal, Heat two portions of the same food
to the same temperature. Blow on just one portion,for a
couple of minutes, then check temperature of both.
2006-07-26 07:58:31 · answer #8 · answered by Answers 5 · 0⤊ 0⤋
yes because it makes the steam go away
2006-07-26 07:16:28 · answer #9 · answered by stranger 2 · 0⤊ 0⤋
yes
2006-07-26 07:11:38 · answer #10 · answered by luckistrike 6 · 0⤊ 0⤋