When you bite into a hot apple pie, why's the liquid more likely to burn your mouth than the crust (same temp)

Question

homework question (science)

Answer 1

It is not due to sugar, but rather, due to water.

Water has a ridiculously high specific heat, which is the amount of heat energy required to change its temperature. To put things into perspective, consider a piece of iron.. When the temperature of iron increases, it has a lot of energy and you'll get burned; iron is storing a lot of energy due to that increase in temperature and it can be said iron has a high specific heat. The specific heat of an equal mass of water is nearly 10 times as great as iron.

So raising the water in the apples of your delicious pie to your temperature of preferences adds a lot of heat to the water, which is transferred to your mouth when you bite.

Answer 2

It's called thermal conductivity and works in much the same way as electrical conductivity.

Liquids have a high thermal conductivity and thus transfer heat a lot quicker than the crust of a pie would.

In analagy to electrical conductivity it is like getting into a bath with a hair dryer. Whether you're in or out of the bath, the hair dryer is at the same voltage but when there is liquid in between it and you, then you are much less likely to get electricuted than when there is only air between it and you (water is a much better electrical conductor than air).

At room temperature touch a wooden bench, a metal bench, a piece of pastry and dip your finger in a glass of water. These are all the same temperature but they will feel different because the materials which are more conductive (such as water and the metal bench) will suck heat out of your hand quicker than those materials which aren't very conductive (wooden bench, pastry).

Hope this helps.

btw solitusfactum has got heat capacity and latent heat mixed up. Latent heat is how much energy is needed to cause a phase change (e.g. from solid to liquid). Heat capacity is how much heat an object stores per unit temperature. The heat capacity will be important but it is unlikely that you will keep the pie in your mouth for long enough for it to unload all its heat. More likely you'll swallow it and it'll burn all the way down (chilli burns on the way out but that's not due to thermodynamics). No, for burning your mouth the issue is thermal conductivity.

Answer 3

using fact they don't look to be a similar temperature. the 2d you're taking the pie out of the oven, 2 issues are happening. The crust will lose it is warmth lots quicker using fact of two motives. it is on the exterior of the pie and could lose warmth quicker besides, plus it has much less liquid than the filling, and beverages carry warmth longer. The filling is likewise insulated by making use of the crust, and straightforward physics and technology will dictate that it wil be warmer than the crust for that reason and each of those listed above.

Answer 4

The crust is far less dense and therefore less conductive. The filling is more dense and more conductive. In addition, the filling is sticky and stays put. The crust crumbs are quickly brushed away by the eating process.

You could just as well ask this question about pizza. The cheese is what burns the *(()() out of your mouth -- not the crust.

Answer 5

I don't know this but I've always assumed it is two things:
1- the crust cools off much much faster than the liquid, so they actually are not the same temperature when you eat them
2- its easier to keep the crust off the roof of your mouth (where i personally always get burned) where as the liquid is much more difficult to direct so it ends up on the more sensitive parts of your mouth and burns you. Just like pizza sauce.

Answer 6

The liquid is a better conductor of heat compared to the crust, thus posessing much more heat. And since the crust is an insulator of heat, it would not have that much heat.

Answer 7

one reason is that liquid sticks to you better, so it's harder to get it off while it's burning you...

also for it's "latent heat". That basically means water holds a lot more heat energy though it's the same actual temp. It takes way more energy to heat water then it does to heat say, metal or carbon. that's also why water doesn't cool as quickly as solids do.
so all the energy it took to heat that liquid is burning your mouth. hope this helps!

Answer 8

The liquid is sugar syrup, solution. It conducts heat bettter than the crust.

Answer 9

The liquid could ( and generally is) be hotter, being contained inside the crust

Answer 10

Liquid suger is in it and the liquid can creep to many portions quickly and retain the heat longer