SpudFiles

@D_hall
yeah I know what you mean but if I was that teacher I would state explicitly that the egg has to be boiled not fried... anyway he should ask the teacher if he hasn't mentioned that

Though, in my opinion he just have to build an efficient burner, add some insulation and use as little water as possible

I dunno if it will be on taste, at school here we're incessantly told to not eat anything from a science lab.

ok, i asked some questions, and here are some more results

the egg must be cooked in-shell
no other energy sources may be used
chemicals may be added to the water (not clear on exothermically reacting chemicals, most likely not allowed)
egg must start at room temp
in/decreased pressure may be used
the egg DID come before the chicken

the winner will be judged on fuel consumption ONLY (10 pts, winner gets 12)
the other grading categories are: sucessfully cooking egg (10pts), ingenuity of design(10 pts) documentation/evaluation (20 pts)

he said in the past, the winner has used somewhere between 1 and 2 grams of fuel

thanks for all your help, keep the suggestions coming

documentation/evaluation (20 pts)

Well there's 40% of the assignment. If you use chemicals in the water, talk about how they change the boiling point of the water to prevent energy waste through latent heating. Discuss the merits of your insulation. Monitor the water temperature. Test it's boiling point after with the chemicals to prove you weren't wasting energy through latent heating.

Generally, your best insulator is a vacuum. Have a look for a small vacuum flask, build the stove on the lid, ventilation holes through the lid and you may be set. Of course, you would be hoping that the flame doesn't affect the integrity of the chamber.

Dead space to the minimum.

Lastly, you could ask someone who's very experienced with cooking how to tell when an eggs cooked (of course, a little hard to tell when it's insulated by vacuum), or something you could add to help it cook quicker (stabbing in the dark here to tell the truth).

Though I'd say adapting the vacuum flask would be the way to go. If you don't want to wreck a good vacuum flask you should have a vacuum pump there, and be able to make your own vacuum shroud to use.

Edit, Vacuum flask = Thermos. Should be able to get a cheap one somewhere. We got some little metal ones for $5 aud. They would probably hold up. Butcher the lid (WITH AS SMALL HOLES AS PRACTICALLY POSSIBLE) for your air in/out.

the only problem with a thermos is that you need two holes in it... one at the bottom for hot air/flame to get into it and another just to exhaust that hot air...

You could have the lid at the top with holes for ventilation of waste gasses (as small as possible), and have another steel tube through the lid which travels to the bottom. You can then feed air into it.

Edit: Example..obviously your dimensions would change. Ventilation through hole in lid, fresh air added through small pipe.

you could use oil instead of trying a pressurized water container, it's how deep frying works, and oil has about half the speciffic heat of water and if I'm not mistaken that should be a benefit

iknowmy3tables wrote:you could use oil instead of trying a pressurized water container, it's how deep frying works, and oil has about half the specific heat of water and if I'm not mistaken that should be a benefit

Good idea. Cooking oil like bran, canola etc shouldn't bugger with the taste/cooking, has a higher boiling point (you should try to control it still, but you won't waste as much energy). Apparently it helps with removal of the shell as well. You should do some test with water, salt water, oil, and a mix of oil/water to see which works well (beforehand).

How to cook perfect hard boiled eggs:

When using a vacuum remember that the egg has a bit of air at the top(the reason you poke a hole into it before boiling!) that would cause it to burst in a vacuum, to avoid this you can either;

-Remove the shell by letting the egg sit in vinegar.
-Poke a hole into the flatter side of the egg before inserting in the vacuum

Also i wonder if putting it into vinegar for so long that the shell is thinned but not entirely gone would help the heat transfer, its made of calcium carbonate so really it depends on how good that conducts heat.

inonickname wrote:You could have the lid at the top with holes for ventilation of waste gasses (as small as possible), and have another steel tube through the lid which travels to the bottom. You can then feed air into it.

Edit: Example..obviously your dimensions would change. Ventilation through hole in lid, fresh air added through small pipe.

I don't think the vents would provide enough oxygen, a burner needs lots of air which is why the are typically left in the open

hmm what if you pumped pure oxygen through that tube, you could buy one at a hardware store just don't blow up the system
if you intend on a pressurized combustion for heat, you have remember an influx of air may speed combustion but it will also cool the system

D_Hall wrote: Hmmm.... I wonder what would happen if you skipped the water and just put the egg over the flame?

I agree with D_Hall and thought: With the limited amount of fuel you are given then why waste energy trying to boil the water.

By carefully poking a hole (with a needle) in the bottom of the egg, you could run a BBQ skewer through it. After you get it through, carefully poke another hole in the top and then push the skewer the rest of the way through.



If there's egg yolk/white oozing out of the egg, cook this area over the open flame first, to seal the egg to the skewer. Googled this info by looking up <a href="http://www.ehow.com/how_2324833_cook-eg ... ">"cooking egg over open flame"</a>

however a rotary style of cooking has it's own heat inefficiencies, while you cook one side the other side gets a chance to cools
an optimum design should heat as much of the egg at the same time as possible while minimizing the heat wasted on heating the surrounding medium

your a lucky person to get building projects with a good creative component, the projects for ENES101 course at my school are horrible students always remember the project as a bad memory, but the professors are two stupid to realize the reason why the projects suck is because they don't have room for creativity. Last year they did hot air balloons, this year they did heart lung machines cool and oxidize the blood solution everyone just turned in variations of bubblers and ice baths because it was the only practical option on a low budget, now they're doing autonomous navigation with lego robotics kits their giving us the same project they gave to elementary school kids, seriously active design engineering is never creative, it's just saying lets use more servos motors and actuator than necessary and then we'll program a computer to control it that is smarter than necessary

sure it wouldn't hurt if you could find some creative way to boil the egg.. but if a simple burner works better there is no need to try something else where the most straight-froward approach works better

How about putting the 20g of fuel in <a href="http://www.tescoma.es/pic/650310.jpg">this</a>

...and heating the egg (with water) in one of <a href="http://www.canningpantry.com/half-pint- ... >these:</a>

The holes in the slat shaker would act like the holes in a stove burner. It would be interesting to see how long the fuel would last... I've injected a very small amount of propane vapor into an empty soda can before and it'll burn out of the open end, for quite a long time.

If you were to utilize the lid on the mason jar - poke a few small holes in the top, to let the steam vent slightly.

I'm no rocket scientist, but I would imagine that a lot of energy will be lost as radiant heat, off of the glass.

Caution; The glass may crack and/or the lid's gasket may melt slightly, to the lid and the jar... Safety glasses, gloves, outside kiddies.