Hot Water Science Experiment

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Andrew R

Andrew R

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Just wondering what ideas everyone could come up with. My science experiment is to make a solar water heater, which I leave out in the sun for a day, then measure the temperature. I can't use a solar panel or anything like that. I think the key is to not think too intricate. Previous, quite effective designs have been simply just painting a can black and letting that sit in the sun or a hot water bottle with the same method. Right now, I'm thinking of painting a can black but putting it in a metal or other reflective surfaced perabola (large semi-circle dish).

Does anyone else have any suggestions? Tips? Anything of the sort. :)
 
Why don't you just make a solar oven? We made those waaayyy back in 4th grade.

People used cardboard boxes and filled them with newspaper and all this crap, but I just used a styrofoam transport container and a toaster oven rack (it was actually one of those zig-zag-like metal trays). If you order something that's frozen and it comes via parcel, it comes in the container filled with dry ice. They're pretty handy. Anyway, put black paper all over it, crumple up some of the black paper and put it on the bottom, put some mirrors at strategic locations, and cover the thing with a piece of plexiglass. We cooked s'mores in 'em. Ours worked the best... our s'mores looked unchanged, but we bit into them and they all just turned to liquid. Hahaha. Ours also managed to keep the squirrels out. The people who left their ovens open had either stolen smores or cold smores.

You could perhaps put your dish into the oven. Make sure your dish is as shallow and huge as possible. The rays will travel through the clear water and heat the dish. A metal dish is a must as well. Try for copper.
 
BMW318_DRIFTER
Just wondering what ideas everyone could come up with. My science experiment is to make a solar water heater, which I leave out in the sun for a day, then measure the temperature. I can't use a solar panel or anything like that. I think the key is to not think too intricate. Previous, quite effective designs have been simply just painting a can black and letting that sit in the sun or a hot water bottle with the same method. Right now, I'm thinking of painting a can black but putting it in a metal or other reflective surfaced perabola (large semi-circle dish).

Does anyone else have any suggestions? Tips? Anything of the sort. :)
Click to expand...

Is this an experiment where you have to heat water then?

How hot do you have to get it?
 
Does it matter if it boils - to the point of all boiling away?
 
Yeah, we put 500mL in at the start of the day, the teachers measure the temperature and at the end of the day, how much water is left.
 
So if you can get it to all boil away, you win?
 
In short, yes, but I need to have as much of that 500mL left at the end as possible, then I have to explain all the 'forces' I guess you could say involved in my design.

Wow, I'm really bad at explaining myself...sorry about that.
 
So... a solar furnace, which would boil that away inside a few seconds and, if it's a good enough build, melt the glass beaker too wouldn't be any good, because you need to heat the water but retain it?
 
Yes, and it will be left in the sun all day so it doesn't have to instantly boil or anything, something that retains heat quite well and steadily increases in temperature would do fine.
 
I'd probably build a solar furnace anyway, just to freak the teacher.

"Okay, let's place the beaker at the focal poi... It's melting... My hand! My hand!"


So, what you need is something which takes advantage of inbound radiation, while minimising outward radiation, convection and conduction.

Minimising convection is easy. Seal the vessel. Sealed vessel = NO convection.
Minimising radiation is harder, but still easy. Highly reflective interior.
Minimising conduction is hardest. Air is a pretty good insulator, so don't bother insulating the sides and top. Mount the apparatus on top of a thick wooden or polystyrene block to insulate it from the ground. Last is the material your apparatus is made from - it needs to admit heat from the outside, but not waste energy heating itself up.


So... I'd use a steel can (not stainless, and certainly not aluminium) with a polished interior - get polishing. If it doesn't polish up, spray it with silver metal spray paint. Spray the exterior of the can with matte black metal spray paint. Also wrap in black card/paper, which will provide an extra barrier to radiation when the metal of the can gets hot.

Get a top for it of the same material - steel, polished on one side, matte black on the other - and seal it tight on. Put a hole in the top and insert some rubber tubing - this will allow the water and thermometer in. Make the hole very tight and seal it in place with rubber sealant. Put a tube-grip on it (small things which fit over a tube and allow you to seal it and unseal it by a small screw) to maintain internal pressure and ensure the water stays liquid - and allowing you to release the pressure gently for insertion of the thermometer (release it slowly, or the energy can vapourise some of the water, which you'll lose). Place the whole apparatus atop a 10cm thick block of polystyrene.

Putting all of this inside a parabolic reflector would be a good move too, so as to increase the received solar radiation by several orders of magnitude. But make sure it isn't TOO high, or you'll burn the cardboard and the steel.

Next step - win.
 
Thanks Famine, that's a much better description of the very general design I had. This is most likely the design I'll go with.

Very helpful hints there.
 
Famine
I'd probably build a solar furnace anyway, just to freak the teacher.

"Okay, let's place the beaker at the focal poi... It's melting... My hand! My hand!"


So, what you need is something which takes advantage of inbound radiation, while minimising outward radiation, convection and conduction.

Minimising convection is easy. Seal the vessel. Sealed vessel = NO convection.
Minimising radiation is harder, but still easy. Highly reflective interior.
Minimising conduction is hardest. Air is a pretty good insulator, so don't bother insulating the sides and top. Mount the apparatus on top of a thick wooden or polystyrene block to insulate it from the ground. Last is the material your apparatus is made from - it needs to admit heat from the outside, but not waste energy heating itself up.


So... I'd use a steel can (not stainless, and certainly not aluminium) with a polished interior - get polishing. If it doesn't polish up, spray it with silver metal spray paint. Spray the exterior of the can with matte black metal spray paint. Also wrap in black card/paper, which will provide an extra barrier to radiation when the metal of the can gets hot.

Get a top for it of the same material - steel, polished on one side, matte black on the other - and seal it tight on. Put a hole in the top and insert some rubber tubing - this will allow the water and thermometer in. Make the hole very tight and seal it in place with rubber sealant. Put a tube-grip on it (small things which fit over a tube and allow you to seal it and unseal it by a small screw) to maintain internal pressure and ensure the water stays liquid - and allowing you to release the pressure gently for insertion of the thermometer (release it slowly, or the energy can vapourise some of the water, which you'll lose). Place the whole apparatus atop a 10cm thick block of polystyrene.

Putting all of this inside a parabolic reflector would be a good move too, so as to increase the received solar radiation by several orders of magnitude. But make sure it isn't TOO high, or you'll burn the cardboard and the steel.

Next step - win.
Click to expand...


:dunce:
 
My solar oven is crying. :(

Famine's apparatus would probably be better for the application. I originally thought you had to cook off as much liquid as possible.
 
I've done this sort of thing for school years ago (damn I'm getting old). I used an old wok, painted black on the back and polished inside, and some clear tubing spiralled in the wok. The water goes in the tubing, which has been sealed at the base and gets sealed at the top with a removable bung. The sun rays go through the water/tube and reflect back through it again from the polished wok.

I think I may have put a spiral of half black, half polished metal strips in the top ridges between the tubes too?
 
Famine
Putting all of this inside a parabolic reflector would be a good move too, so as to increase the received solar radiation by several orders of magnitude.
Click to expand...
Yes, because everyone has one of those just lying around. I suppose he could just raid the local physics department :lol:
 
I suppose he could just go to the store and buy a wok. Same ****. Famine, why use a steel can when you can use copper? Do you think the copper will retain heat that should be going into the water or something?
 
Omnis
I suppose he could just go to the store and buy a wok. Same ****. Famine, why use a steel can when you can use copper? Do you think the copper will retain heat that should be going into the water or something?
Click to expand...

Copper - as with aluminium - is a very good thermal conductor. This means that as well as heating up quickly, it'll conduct heat away from where it's needed - the water - and start to radiate sooner. Since it's an all-day job, you need something which is a relatively poor conductor. Stainless steel is too poor, but regular steel should do the job nicely.

kylenhat
Yes, because everyone has one of those just lying around. I suppose he could just raid the local physics department
Click to expand...

You can make one with some cardboard and a sheet of aluminium foil.

Better yet, get down the scrappy and help yourself to an old household satellite dish - it even has the focal point of the parabola already worked out for you.
 
Famine
it even has the focal point of the parabola already worked out for you.
Click to expand...
Aye, there's the rub. Sure, you can make a concave reflector yourself, but unless you're exceptionally skilled at doing so, it won't have the fire-starting power of a real, purpose-built one :)
 
Don't need it for just making some water slightly hotter...
 
I have started a trend on GTP.

I bring the "Im In Ur" Pics here, and 20 people put it in their avatars/titles/locations :lol:.
 
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Line the inside of it with some sort of reflective material( tin foil works best) and put it twods the sun(try doing this when its at its most verticle position, 90 degrees)

Make sure you cut the bottom out so you have somewhere to put the water

Should be able to get 100+F out of it in 5> minutes
 
not sure if this is allowed or if someone has already used it but use a magnifing glass or some mirrors to focus the suns rays onto some dry timber and create a fire and then use the fire to heat the water i dont think this would be cheating because you are still using the suns rays as the primary heat source
 

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