Energy Content of Food

[@Trodat1009]

Great stuff! Nice to see a demo of this lab and how you use probeware.

[@kys7849]

Who else watching this in quarantine for science/physivs

[@ahmadabdullah8153]

Question: what material's have you used in this video

[@Dancerloveislife]

I have a question, what happens to the calories once they are "released"?I read online somewhere that when you burn food the calories don't get destroyed but they just get released into the air. Does this mean if there is a kitchen fire for example, that there are tons and tons of calories in the air or if you're eating near a restaurant that is on fire could these calories that were released into the air from the burnt food get into your food? ? I've also read that the air cannot hold the calories content but I'm not sure which is correct :/ sorry if it's a stupid question.

[@pascoscientific]

+Dancerloveislife Great question! When food burns, thermal (heat) energy is released into everything surrounding the burning food, including the air. The result is a temporary increase in temperature due to added heat. We use the unit “calories” to measure energy from heat. Once heat (measured in cal) is released from the burning food, it continues to spread out in all directions through more and more and more air and other surrounding matter. So if you are eating food outside of a burning restaurant, you and your food feel the heat because you are absorbing thermal/heat energy measured in calories. The energy/heat absorbed by you and your food will eventually get transferred to other matter that is cooler and will continue to spread out to everything else in your surroundings. The energy eventually makes its way to the atmosphere, where it can be exchanged to space, and temperature equilibrium is reached.

[@davidalvarez9135]

Excellent tool for teachers. Thanks you so much.

[@kys7849]

I am in grade 6 and had to watch it a 1000000000000 times before I understood it

[@katerinanyankina7875]

You have to minimise energy loss to environment as much as you can - you can insulate the can (wrap it in corrugated cardboard with foil around it, you can also make sort of foil skirt at the bottom of water can to reduce radiation losses from a flame)

[@sulemanqadir23]

Great video..

[@ssand894]

QUESTION: How do you reduce the heat loss? Wouldn't there be insignificant errors occurring because there is no essential protection around the food combustion?

[@pascoscientific]

While there is significant heat loss, this simplified setup still reveals the differences in energy content between the sugary marshmallow and fatty peanut. To estimate the heat loss, you could compare the calories per gram determined at 12:01 to published values for these foods. There's a discussion of reducing errors at 15:15. Note the slide references a bomb calorimeter, which professionals use for accurate results.

[@funsky77]

What year level would teach this? I don't remember learning this at high school at all. 🙄

[@needarandomname4330]

Question: If we're recording the food with the food holder together and then we record it again after it's burned then how do we calculate the amount of calories per gram burned? Wouldn't that mass change simply be the amount of carbohydrates and/or lipids it contained? Wouldn't we use calories burned/grams of food (not just part of it) ?.........or am I just missing something?

[@pascoscientific]

+Jibraeel Karim Thanks for your question. The technique shown in the video does calculate the calories per gram burned. In this activity, we're seeking a general comparison of the energy content of different food types, and the burning technique shown does not guarantee burning of the complete original sample. You might be interested to learn about the more precise technique of using a bomb calorimeter to more completely combust the food to better determine the calories per gram of food

[@needarandomname4330]

pascoscientific Cool. thanks for your reply! :D

[@robertbeach71]

What do you propose to do to overcome foods that aren’t as flammable as marshmallows? Like a granola bar?

[@pascoscientific]

The soda can calorimeter works best with foods that can be ignited with a match. Granola would require a more robust, sealed calorimeter (a bomb calorimeter) because it cannot be ignited by a match.

[@jeremiahcastro9700]

Hmmm very interesting...so naturally water is *0 Calories* because it doesn't burn? My understanding so far is that since water is used to convert the energy in the food to be useful and transport it...the water shouldn't burn...I will have to look more closely into the connection with water and energy...

[@jeremiahcastro9700]

Alright so while it wasn't explicitly mentioned here I learned that the reason whybwater is used as a measure for calories is not because it can burn but, water acts as the perfect medium for tracking the amount of energy is transferred from the heat of the fire! Very, very, very cool!