Do eggs create their own heat?

[Stockwell]

Well, this is all interesting.
Its all news to me.
Eggs producing their own heat...?? Maybe, I really don't know. Certainly decomposition produces heat, as does fermentation, but normal developing ectotherms producing heat.. Maybe, I've never investigated that before, and can't say I've noticed any such effect in my years of incubation.

The only comments I can make involves the thermodynamics and instrumentation.
To start with, most thermometers are not accurate, so extreme care must be taken to utilize the same thermometer in all experiments. I assume this is being done, but even battery voltage will effect the reading on all electronic thermometers.
I discovered that several years back.
I have a big collection of thermometers,and tend to collect them, and most indoor/ outdoor probe type read higher as the battery gets weaker. This can vary by almost 2 degrees F.Somewhat opposite to what one might think.
Lab grade spirit or mercury thermometers(non electronic) can be used for all tests but also have intrinsic problems, primarily that they have too much mass to respond quickly.
Another consideration is that adding eggs to an egg box, compeletely changes the thermal dynamics of the box, because of the increased mass.
All incubators will have heat up and cool down curves,(think of a temp vs time graph) which is based on the differential of the thermostat, and the BTU output of the heat source vs the outside ambient loss factor.
Most thermometers won't accurately reflect the heat up and cool down curve, because the response time of the thermometers will be different than that of the air in the controlled space.
Adding mass to any system has the effect of dampening and averaging the extremes.
Depending on the overshoot and differential of the system, the egg mass might read higher than the same box full of air if the air temp spikes after T stat turns off due to the overshoot effect(heat still being emited after switch off)
If this spike is rather quick but high, it may not have been detected by the thermometer in the initial tests with a bare box. The egg mass however will tend to increase to the mean of the curve, creating the appearance of the eggs adding heat.
But are they creating their own heat, or simply storing part of the overshoot that was previously unmeasurable with thermal response time of the measuring instrument.??

This hypothesis of eggs producing internal heat should be easy to confirm.
I suggest someone take some measurements of an empty egg box fully loaded with moist egg media over a period of days.
Then simply fill the space with chicken eggs, known to be dead but approximating the mass of a live egg clutch.
See if your reading goes up!!
If it does, the phenomenon has nothing to due with life in the shell, but is an artifact of the measurement instrumentation and thermal response time(and changes in rates of evaporation)

[Stockwell]

Another comment about water bath , open water and even moist vermiculite in incubation systems.

Systems with a water component introduce another variable in addition to the considerations above.
Water, or water laden egg media will cool surroundings as evaporation takes place. This process is known as the "latent heat of evaporation" and is well known to anyone with fish tanks.
Any glass ,tank or vessel of water where evaporation is taking place will always be cooler than the surrounding air. (This is also why overheated snakes will sit in water bowls)
In the process of incubator design, I have discovered that moist egg boxes with holes, are cooler than the surrounding air in the incubator, but as the egg box dries out, the temperature goes up. This increase in temp isn't due to life in the eggs, but is more a factor of less evaporation taking place as the egg media loses water. The degree of change has to do with the rate of evaporation but is generally around a degree F.
So you should also consider that eggs placed on or over a water laden media will restrict air flow, thus reduce evaporation, and that reduced rate of evaporation, might be reflected in an increase in egg temp, but such an increase should never excede the peak air temp of the system.
So when talking about egg temps varying by a mere degree or so, there are lots of considerations before concluding that the eggs themselves are generating their own internal heat.

[Scales Zoo]

Good post Roy. Thank you.

First off. I'm not sure the brand of my thermometers with probes(will check tommorrow), but they are very accurate to each other. I've put them together and measured the exact same temps. I've also switched them between egg boxes, and with in 2 minutes, each is reading exactly what the other was just previously. Yes, you were right, I did confirm this (your proud of me aren't ya!).

And I am quite sure I took care of any over shoot, radiant, or latent heat issues that might have been inherent. I insulated the bottom tub, and my fan circulates the air in the incubator very quickly. The heat doesn't come on very often, or for very long, and the "always on" fan (which I added in conjunction to the turbo fan that comes on during heating) is pointed to take heat away from the element while it is running and after it shuts off

I think I should switch the rubbermades around(from top to bottom), and see if this effects any difference. It would rule out any of the above mentioned variables, I think.

I've been reading more, and it does seem as though python eggs do generate heat during development. Monitor lizards produce heat during digestion, chicken eggs create heat during development, and the GTP guys have mentioned eggs creating heat. I do have a strong gut feeling that this is what is happening with my burm eggs - I will continue testing to try and disprove that - you know how I am.

Science is great kids!

Ryan

[Stockwell]

Ryan, why not try my chicken egg test, using identical containers and identical moist substrate. I really think rates of evaporation could have a huge bearing on the outcome of experiments. And are you temps actually higher than your highest peak air temperature? A box full of eggs, restricts evaporation by covering the air exchange to the substrate.
Certainly if there is anything to this theory of eggs producing their own heat, there should be a marked difference in the outcome of tests with a box of python eggs, vs a box of dead chicken eggs, in identical setups, with identically prepared substrates.

[crocdoc]

Roy, Ryan and I haven't actually come up with the idea that eggs give off metabolic heat, it has been recorded before by others.

However, I do have a comment regarding this statement: "If this spike is rather quick but high, it may not have been detected by the thermometer in the initial tests with a bare box. The egg mass however will tend to increase to the mean of the curve, creating the appearance of the eggs adding heat."

I would find it odd that the thermal inertia of the thermometer's sensor would be great enough that a temperature spike would not be detected, yet the temperature spike would be enough to increase the temperature of eggs (which have a much greater thermal inertia).

I should also add that I noticed the difference with five well spaced monitor eggs in a 7 litre egg box, so I'd find it hard to imagine the reduction in evaporation making that much of a difference.

[chamitch]

stockwell did point out some good points but i dont think it explains it all.

even though snakes are considered cold blood, this is not tottaly true. when there is energy involved ie digestion and use of the protien, fat for energy. there is heat emited from the chemical reactions in that procces.

also think about that even plants produce some heat. i belive thats how they bust narcotics being grown in a feild.

so using this idea the changes in chemical make up in a egg would indeed give off heat. yes it needs heat from the incubator to start the reaction but after that more heat can be produced from the changing of aminos and all the other goodies inside.

oh how i love science
peace

[Jeff_Favelle]

Ahhhh that makes sense. I could see the temps rising then. I'm sure of it. Especially during the last 2 weeks of incubation. With biggie-sized Burm eggs, that would definitely be something to watch for.

Maybe more holes would be good, as then there would be more lee-way with the air from the incubator getting in, and the "heated" egg-air being able to escape.

Let us know how it goes.

[Aug]

Don't mean to bud in. I just want to help out.

From what i know, eggs should produce heat. In fact "cold blooded" organisms do as well. The fundamental biochemistry of all organisms throughout evolution has almost remained constant-especially lipid and carbohydrate metabolisms to say the least.

In embryogenesis, there are tones and tones of cell migrations, that require the expenditure of transcient, highly energetic molecues, such as ATP, UTP, GTP etc. All organisms are not 100% efficient in transfering/coupling this molecular energy into mechanical motion or other processes. Even then many cytoskeletal elements (IE, actin and microtubulin) breakdown the energy molecules to create cell dynamics.

It get's pretty nasty from there. But trust me, every organism gives off heat. it's a matter of how much heat.

With you current setup you may want to check the thermodynamics like stockwell mentioned, as it may play a greater role in uneven heat distribution. However, there are many variables when considering 1 degree.

Just my 2 cents.
Augustin

[Scales Zoo]

Originally posted by Stockwell
Ryan, why not try my chicken egg test, using identical containers and identical moist substrate.

I will.

[B] And are you temps actually higher than your highest peak air temperature?[B/]

Absolutely. The heat doesn't come on that often, I've got a fan that really blows the air around and keeps things even. The thermometers move at .1 F - and will do it in 10 seconds if the temp rises that much. I've measured the temps in the incubator, and when they are doing the 88.0 - 88.3 thing - the one egg box is at 90.5, the other one is at 88.6. I have full trust in these thermometers, they've been with me a while and I've really tested them out, - they record a low and high setting so I can check how things have been while I was away.

Certainly if there is anything to this theory of eggs producing their own heat, there should be a marked difference in the outcome of tests with a box of python eggs, vs a box of dead chicken eggs, in identical setups, with identically prepared substrates.

I've got a box full of chicken eggs, I'll put them on verm and in a tub - and get back to you.

Ryan

[Jeff_Favelle]

Hmmmmm......Roy, I think maybe I'd have to agree with you. And your posts totally re-confirms my love for my no-substrate water incubators!! Heat the water which heats the air! There are no spikes in temperatures because the water is a HUGE buffer of heat. Small heater, LARGE water source = NO over-shooting in heat! Woo-hoo!

[Scales Zoo]

Originally posted by Aug


In embryogenesis, there are tones and tones of cell migrations, that require the expenditure of transcient, highly energetic molecues, such as ATP, UTP, GTP etc.

Releasing ATP, creating heat - that's it!

Now I remember who I was talking to about this. Thank you for refreshing my memory!

Ryan

[Scales Zoo]

Originally posted by Jeff_Favelle
Hmmmmm......Roy, I think maybe I'd have to agree with you. And your posts totally re-confirms my love for my no-substrate water incubators!! Heat the water which heats the air!

I'm doing this next as well. I like the principals behind it (100% humidity and no wet verm touching bottom eggs)

There are no spikes in temperatures because the water is a HUGE buffer of heat. Small heater, LARGE water source = NO over-shooting in heat! Woo-hoo!

I am using a heat source from a small hovabator in a large fridge, with an extra fan. The water and verm and eggs must weight over 30 lbs. The heat source does not come on often at all, and when it does, the fans blow any warm air away. I do not beleive my heat source is too much for my capacity (2 Large water sources and egg masses)

But yeah, agreed, water and an accurate fish heater (with a non vertically orientated incubator like this fridge) would definitely keep steady temps.

Ryan

[Jeff_Favelle]

And Ryan, on top of the fish heater, you can have a Helix as a back up. Set the fish heater to have the incubator at 89.5F, and then set the Helix to 90F. DOUBLE protection! The incubator would be fooool proof, provided the power didn't go out!

Cheers.

[crocdoc]

haha... I had the power go out in my neighbourhood a month or so ago, on our first cool night of autumn. Any other night before or after that one night wouldn't have been an issue. Whenever I rang the electricity company's emergency information line, I got a recorded message that was upgraded on the hour. When I rang at 8pm, the message said the problem would be sorted by 9pm. When I rang at 9:10, the message said 10pm. When I rang at 10:10... well, you know where this is heading.

At 11pm I was contemplating the idea of lifting the whole incubator into my truck and driving it to my office, to plug in there. The temperature of the incubator was dropping at roughly .5C/hour, so by the time the power switched back on near midnight the temperature hadn't dropped enough to worry about. It's likely the eggs inside the egg boxes didn't experience much of a drop at all.

[Scales Zoo]

Jeff, what heat source do you use with the helix as back up protection?

Croc Doc - In Canada most of our hot water heaters are run with natural gas, so we could just fill warm 2 litre pop bottles (do you have pop in Australia, or just beer - hehe) with warm water and put them in the incubator to keep temps stable during a power outage.

Ryan