The Greenhouse Gas Demo
A really simple way to demonstrate the Greenhouse Gas Effect of carbon dioxide two bottles filled partially with water put a seltzer tablet in one to produce CO2 close the lid put in front of a heat lamp and measure the temperature

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This discusses a short, but very effective and dramatic demo to show the effect on temperature of increased levels of carbon dioxide.


ufewl : lol the lamp is only pointing at the CO2 bottle!!! Look it light up like a Christmas tree!!

jeffrey tolliver : How much CO2 is that bottle? What about the added pressure? I’m more curious to see how much effect there is by adding like 100 PPM of CO2

Andreas - : Nice attempts when the lamp is aligned with the left bottle...... Be fair and aim the lamp towards the middle.

Herzelich Klausewitz : The radiation on the two bottles seems to be inequal... can you measure the temperature outside on each bottle? How high is the CO2 concentration in your experiments? That is a pseudo-scientific experiment.

Feat. Cicero : Probably the only good experiment about CO2 and temperature on YouTube. Thank you!!

Lundqvj RL : In all fairness would not the bubbles in the co2 bottle be enough to trap more of the light/heat giving you the difference? Like mini greenhouse within a greenhouse?

Emsnews Supkis : It is obvious that the BUBBLE ACTION is causing the CO2 bottle to refract much, much more light than the bottle with no bubbles. When light bounces off of many tiny 'mirrors' this way, it heats up the water more than still water with no bubbles. The fact that this entire 'experiment' ignores the issue of shining light on bubbles shows the shallowness of the intellectual game here, this is why the light shining back onto the shiny table surface shows virtually no light reflected from the pure bottle while the one with the pills is brilliantly lit up like VENUS which is mostly CO2 atmosphere and totally cloudy.

iviewthetube : Was the chemical reaction of the Alka-Seltzer mixing with water endothermic or exothermic?

ligonapProduktion : *What a big fail.* I can already guess the result without knowing where the CO2 is. The bottle on the left. Why? It's simple. It is the bottle that is irradiated much more. The CO2 concentration is also much too high. In the atmosphere the CO2 concentration is only 0.04 %. Ergo: Absolutely not scientific! Busted!!

Vienna Flyer : Any idea how much pressure effects temperature??

Main 1 : anyone know of a similar lab experiment to this with better controls? This one has too many problems

IskurBlast : And that has been published in the peer reviewed literature so shut it!! Wagner et al. Climate change in a shoebox: Right result, wrong physics American Journal of Physics, Volume 78, Issue 5, pp. 536-540 (2010).

IskurBlast : You would get the same result if you used Argon which has no IR properties.

IskurBlast : Why would a paper need to be written that CO2 in a bottle is an example of specific heat capacity and not IR trapping. That is the established science.

64jcl : Fantastic. Now go write a scientific paper on this and get it peer reviewed. I am sure the scientific community would love to hear an alternative that can refute the established science...

IskurBlast : Because you aren't showing the greenhouse gas effect. The CO2 has a different specific heat capacity than air . That is all your are showing. The IR effects of CO2 over such a short distance is so small you cant measure it with a typical thermometer the only way it can be measured is with expensive spectroscopic equipment.

john kosowski : 64, is there a difference between a container and an atmosphere? If so, what is the difference?

john kosowski : Is our atmosphere encapsulated in a plastic bottle? What was the change in CO2? Was there a pressure change in the CO2 bottle? Too many other variables to make this a good experiment, as noted by all of the comments. It doesn't mean that there is no GHE, but it sure doesn't mean that there is one either. I would be more interested in a scientific explanation of how CO2 in the atmosphere which is at a lower temperature cause the earth, which is at a higher temperature, to heat up. Thanks.

grindupBaker : Some genius brainiac CO2pirate here says it's not the CO2 & heat lamp, but CO2pirate is too proud in his brainy magnificence to tell the rest of the world what it really is. Hey brainy CO2pirate I figured it out right away. Erik is far closer to bottle 2 and he clearly has "morning breath". where's my prize ?

grindupBaker : Erik could ask the commenters to do the science & math of chemical heat and how much that would heat the water but since they are too lazy and don't have the mental equipment he could suggest they simply repeat the Alka-Seltzer experiment with no heat lamp but everything else the same and compare the temperature rise caused in 55 minutes with the heat lamp one. Duh. Does our species deserve to survive ?

Gustavo Naspolini : The result is not conclusive to me. 1) I'm sure you should turn the lamp on only after several hours (maybe a day) so that the effect of the effeverscence on temperature is cancelled. 2) MAYBE you should equalize the pressure of both bottles by means of releasing the pressure of the carbonated one until it reaches the atmospheric pressure (as that's the pressure of the non-carbonated one). I say "MAYBE" because I dont have full understanding of the effect of CO2 on the atmosphere.

Victor Hugo Soares : Hey! I have a doubt. Sorry for a stupid question.. but have so many time that i studied it at high school.. that i dont remember anymore.. =p So, the question is: Is the reaction NaCO3 + H2O an exothermic reaction?

billybush111 : I would assume then, that if you pulled the stopper and released the pressure, the temperature would immediately drop to that of the CO2-free container. Why don't you try that experiment and share the results with us?

GEXGE11 : Well wouldn't the pressure change dramatically in the second bottle? alowing for a major gas mass to absorb more thermic energy? I think the experiment in order to be vlalid should introduce co2 molecules to the point that they reach 500 ppm 600 ppm etc to see if Co2 has the properties that it's claimed to have.

64jcl : Are you trying to explain away the fact that CO2 traps heat? Please be clear when you post this that you think that all the other things you conjure up here have scientific significance over the proven fact that CO2 traps heat. For what I know some of them might have an effect, but how much? It still doesnt change the fact that CO2 is a greenhouse gas.

Jonathan Gal : Also, the reaction of the Alka Selzer with water is - I think - a heat generating reaction ... a source of heat in the CO2 bottle, which is not present in the control bottle and could also explain the temperature differential.

Jonathan Gal : I agree with Paul Kuhns. The temp difference could be explained by pressure buildup in the CO2 bottle. The experiment needs some more sophisticated equipment, in order to ensure that the temp difference is not driven by a pressure difference. The bottles should each have a pressure release valve that allows gas to escape to equalize the pressure. Also CO2 sensors, humidity sensors, and pressure sensors. Monitor all three, and also temperature, of course.

Norman Baratheon : the experiment is probably correct and you are mad about it, so you want desperately to believe it is wrong, and you want us to explain you why it might be wrong. But you are not brave enough to admit it, so you try to impress us and make us believe that you already know why it is wrong. But you failed miserably because I'm smarter than you and I caught you. Otherwise you could just have explained to us why it is "total bunkum" like you say.

Madbastard : Unfortunately Increased pressure in the bottle means increased heat. The increased gas pressure enables more molecules to be excited and therefore more heat is trapped in a smaller area. You could do this experiment with oxygen and as long as the pressure was the same I believe the results would be very similar.

c02Pirate : This is without doubt the most stupid example of C02 warming I've ever seen. There are more mistakes, misinterpretations and straight out scientific ignorance than I care to mention. This silly exercise doesn't even come close to emulating what the GHG hypothesis states - it is total bunkum. Anyone care to illuminate the ignorant on how this silly exercise really works? Hint - it has NOTHING to do with C02. Anyone?

Wilbert Robichaud : with wet droughts and dry floods.

Cyrus Slapatich : LOL. I'm sure you could probably pass that off to the Climate crowd as science.

Wilbert Robichaud : LOL ..and by removing some they will be able to make Africa cooler ... a real man made global temperature control. We could even apply for the kind of temperature we want for holidays . That would create a lot of job since we will be able to Pre Order...a climate reservation. :-)

badlove : That's nice. Now try to do the same experiment by simply doubling the volume of CO2 in the air in the container. 400 ppm is 1 part per 2500. Not sure how many alka-seltzer tablets that equates to, but I am sure that it is such a small fraction of a tablet that you wouldn't even be able to measure and cut it with the simple material you seem to have at hand.

Cyrus Slapatich : They are now, as we speak trying to find a way to pepper the atmosphere with Alka Seltzer.

Cyrus Slapatich : Despite all the half assed attempts to decrease emissions of CO2, they have increased instead. The earth's temperature has not increased in at least a dozen years. Global sea level rise has not happened either. That tells me that this is another Y2K money grabbing scam except way bigger.

JosephA W : The science was figured out over 100 years ago using math. Anyway cleaning up the mess we already made will create jobs. Every regulation creates jobs, like all the air quality test equipment and scubbers that have been installed in oil refineries. We in Los Angeles have seen incredible improvements in Air Quality and Sea Water Quality thanks to increased environmental concerns and activities.

Coke Supply : The reason for the temperature increase is that carbon dioxide molecules absorb infrared radiation at a particular wavelength and emit it at different wavelengths. The emitted radiation cannot pass back through the container at that wavelength, and so the heat accumulates. THIS EXPERIMENT DOES NOT PROVE THE ANTHROPOGENIC GLOBAL WARMING HYPOTHESIS. It merely demonstrates how plastic can be used as an alternative to glass when building greenhouses.

xYondaimexJD : This experiment is very misleading. Guy-Lussac's law tells us that absolute pressure is directly proportional to absolute temperature. By adding two tablets into a fairly closed bottle, he increased the total number of moles of gas which increases the total pressure. Naturally this increases the temperature since more molecules leads to more collisions and higher average kinetic energy. The differences in temperatures between the two bottles should actually be higher, but the fact that he used a crappy make-shift system, led to the observed results. The better experiment should have been to fill a chamber with a known concentration of CO2 and let one bottle equilibrate in the chamber for a few minutes, careful to keep the temperatures the same for both samples. Perfectly seal both bottles with silicon and perhaps use a thermo-coupler. Confirm that the starting temps are indeed the same prior to exposure to heat lamp and then start the experiment.

Wilbert Robichaud : Will it get warmer if you double the amount of Alka Seltzer?

Vooty13 : I like the graph comparing the two bottle temperatures. There is even a dip at about 40 minutes. Maybe that's the water absorbing heat from the warmer gas above it like the oceans absorb heat from the atmosphere?

Erik Christensen : Hi Emma., I used Alka-selzer tablets (generic versions work fine too). These are effervescent tablets to help with head and stomach aches. I am sure there must something similar in Australia - ask you local chemist. Cheers, Erik

Emma Lynch : Hi, I am a teacher from Australia and would like to know what exactly you put in the CO2 bottle. Thanks

Stephen Taylor : If you think you've found a flaw in this experiment - by all means, repeat the experiment (for all of $20 & 30 mins work) and _demonstrate_ what's wrong, you would get a nobel peace prize for upending hundreds of years of basic physics. This isn't an experiment, for chrissakes, it's a demonstration you can do in a year 10 classroom! If you think cutting edge science happens in a year 10 classroom, you probably need to adjust your expectations of what we have figured out in the last 200-so years. Finally - the only people denying CO2 is a GHG are politicians. If you trust them over scientists, we really are doomed.

SciCad : It would be more scientific to keep your responses direct, without ad hominum attacks (name calling). There needs to be a third bottle with co2 and a fourth with air that are kept in the dark. This demonstration doesn't account for either the build up in pressure or the heat of the dissolution of the tablet in the h2o. It would be even better if: 1. The concentration of co2 in the co2 bottle were actually measured; 2. Another 2 bottles were used that had the AD1750 concentrations of co2 in air.

64jcl : Why are so many people in denial about these CO2 experiments clearly showing that CO2 i a greenhouse gas. I have seen many videos here showing the same and the comments are so full of people with denial that the physics cant be believed. Do you believe 2+2=4 ? Well thats math. CO2 added to a container (or atmosphere) increase the temperature... thats just Physics.

Theo Collins : mitekillem Pressure allows heat to transfer faster? Where do you get that? Pressure may cause heat, but not nearly enough to raise the temperature of half a bottle of water by nine degrees. If so, every time you had Alka Seltzer. the water would be steaming hot. Noticed that?

Daniel Gregory : You realize that by adding the alka seltzer you increased the volume of the bottle, thus adding pressure to the mix. Pressure allows heat to transfer faster.

Kevin O'Neill : Just a thought, If the carbon dioxide released was increasing the pressure in the soda bottle (as he said the stopper was fitted tightly at the top) using the equation pV=nrT wouldn't that heat up the water anyway? This wouldn't be a property of the atmosphere as an increase in pressure would just mean more air would leave the atmosphere.