Below: Laboratory experiment on carbon dioxide's effect on atmospheric temperature

 

1. Radiation in general
2. Greenhouse effect
3. How does the greenhouse effect work?
4. Which are the greenhouse gases?
5. Carbon dioxide as a greenhouse gas - laboratory experiment

Radiation in general

Modern science says that the sun radiates a variety of electromagnetic waves. Some of these are visible light. Other radiation is not visible but can be felt and experienced as heat e.g. infrared radiation (IR radiation). This radiation is experienced as pleasant and makes us gladly stay in the sun (sunshine). The part of the solar radiation that gives rise to sunburn is the UV radiation. It is reduced in the atmosphere through the ozone layer but some pass through it down to earth.

Electromagnetic waves with wave-lengths between 290-400 nm (nanometers) constitute part of the UV radiation. This is reduced by the ozone layer.

Electromagnetic waves with wave-lengths between 400-700 nm constitute visible light. These are represented by the colors of the visible rainbow.

Electromagnetic waves with wave-lengths between 700-10000 nm constitute infrared (IR) radiation - heat radiation.


Greenhouse effect

The greenhouse effect evens out the temperature on earth so that the temperature variations between day and night are reduced. The greenhouse effect also raises the temperature in the atmosphere about: 30 ^oC.

One summer day in Sweden we can have about 20 ^oC and at night maybe 10 ^oC. This means that the temperature difference is about: 10 ^oC. In winter time the difference between day and night is about the same. This temperature difference can be compared with that in the desert where the temperature can reach 50 ^oC during daytime and some minus degrees at night. Larger temperature differences do not occur very often on earth. The reason is that we have an atmosphere that evens out the temperatures.

If we take the planet mars as a reference we can say that it almost lacks atmosphere. During daytime, mars has an atmospheric temperature of perhaps 15 ^oC maximum, while at night time maybe –150 ^oC. This means that the planet is practically uninhabitable unless one digs and creates entire underground artificial cities. Thus, the earth is the only planet in our solar system that can harbor organic / biological life.

How does the greenhouse effect work?


Our atmosphere has slowly changed since the beginning of time. Initially it consisted of water vapor, sulfuric acid, carbon dioxide, ammonia and other unpleasant gases. The earth was initially uninhabitable. As the geological activity gradually decreased, oxygen began to be produced by the world oceans. Teal algae used the carbon dioxide dissolved in the water and instead created oxygen. The oxygen began to be stored in the oceans and also entered the atmosphere. Today we have an atmosphere consisting of: 21% oxygen, 0.04% carbon dioxide, 78% nitrogen gas and a varying amount of water vapor (1-4%) and certain noble gases, etc.

Water vapor and carbon dioxide actively participate in the greenhouse effect. These substances have the ability to absorb long-wave radiation and later send it on. This means that the long-wave heat radiation is kept close to the earth's surface - let's take an example:

The sun is shining on earth. The sun transmits all possible wavelengths and some of them hit the earth's surface. Short-wave UV radiation is largely stopped by the ozone layer. The part of the radiation that passes this obstacle reaches the earth's surface. Here the radiation energy is absorbed and the earth emits this energy as long-wave heat radiation. This thermal radiation (IR) is absorbed by water vapor and other greenhouse gases present in the atmosphere. The atmosphere thus takes care of the heat. The heat radiation is then sent between the greenhouse gases in the atmosphere and the heat is retained. The sun's long-wave radiation can be directly absorbed by the earth's atmosphere. On the whole, one can thus say that both the long-wave and short-wave radiation of the sun are used by the greenhouse gases for the warming of the earth's atmosphere.

Which, then, are the greenhouse gases?

The natural greenhouse gas is water vapor and to a very limited extent carbon dioxide (poor one, se laboratory experiment below). These increase the average temperature of the earth to 15^oC. Without these, the earth's atmosphere would have had an average temperature of –18 ^oC. We see that the natural greenhouse effect leads to a temperature rise of about: 30 ^oC. Without the greenhouse effect, the earth would have been uninhabitable. Water vapor is by far the most important greenhouse gas.

The greenhouse gases that humans are responsible for are: carbon dioxide, freon, methane, dinitrogene oxide, ozone and certain particles that we release into the atmosphere - dust and similar particles.

Methane gas is naturally formed by the decomposition of organic material. The gas comes from rice crops, emissions from coal mines and livestock management.

The store up of carbon dioxide increases as man combusts e.g. oil, coal, natural gas and wood. The carbon dioxide concentration in the atmosphere has increased slightly since 1850 (the industrial revolution). But temperature data says that first the temperature was raised and then the carbon dioxide concentration in the atmosphere was raised (lecture by Prof. Tim Ball). A little colder period ended in 1840 and the temperature rose, ie. natural variations in the sun. The carbon dioxide additions that man contributes with are small when we compare to a huge volcanic eruption. Of the 0.04% CO₂ of the atmosphere, man is said to contribute with 3.4%, ie. 3.4% of 0.04% yielding: 0.00136%, 13.6 ppm.


Laboratory experiment arrangement

Task: Determine if carbon dioxide has a warming or cooling effect as "greenhouse gas".

Material: 2 thermometers (preferably digital thermometers), two mineral water bottles with carbonated water, aluminum foil, silver tape, space behind sunny window.

Arrangement: The thermometers must be synchronous, i.e. showing the same "temperature" (^oC) at the same temperature. They should show 0 ^oC in ice water and 100 ^oC in boiling water. If they would deviate a little, then one must find out how they differ from one another.

Remove the labels from the pet bottles. It's easy if the labels are plastic and are loose. Pour water from the pet bottles so that there is about 7 cm of water left in one bottle. Let all the carbonic acid (carbon dioxide solved in water) in this bottle be degassed for a few days. Shake the bottle and have open cap. Make a small hole in the cap so that either a laboratory thermometer (rod thermometer) or digital thermometer can have its sensor about 3 cm down in the bottle. You can melt hole in the cap with a metal awl heated over a candle. Fix the thermometer's sensor with duct tape and don't leave the sensor in contact with the inner wall of the bottle but it should be free. Make sure the cap of the second bottle also gets a hole with the thermometer sensor in the same way as in the first bottle. Fix with duct tape and seal as good as you can. Let the amount of water in the second bottle be equal to that in the first bottle. Leave the carbonic acid in the bottle. Cover the top of the pet bottles equally with aluminum foil so that the sun cannot shine directly on the sensors. Leave both bottles behind window towards the south and wait for sunshine. Make sure the gas pressures in the bottles are the same, i.e. gas must be able to pass out or into the bottles depending on different air pressures - there must be the same pressure conditions in both bottles. This is achieved even if you seal well with duct tape.

Set-up: acc. figure below, and as described in the text under "arrangement". You can execute the experiment in different sunny windows to see possible deviations.

Result: The consistency of the thermometers: The thermometers show the same temperature at the same "temperature".


The picture shows the experiment at night at room temperature (the radiator is not on).

Sunlight temperature (pictured below): bottle # 1, which has only atmospheric water vapor above the surface of the water (common air), starts to get a higher temperature compared to bottle # 2, which has extra carbon dioxide in its atmospheric gas. As can be seen in the picture below, the temperatures differ about one degree Celsius.

At night without sun exposure, it was the same temperature in both bottles. So it was night after night and even day after day when the sun was not on. The temperature was the same in both bottles. As soon as the sun began to shine on the experiment and the temperature increased, a temperature deviation between the bottles of about a degree Celsius occurred. The experiment was up for about two weeks and the result was the same every time the sun shone on the bottles and especially when the temperature reached 30 degrees or more. Initially, the carbon dioxide concentration in bottle 2 needed to decrease a little before we reached the elevated carbon dioxide levels that caused the temperature drop during sunshine.

Conclusion: Carbon dioxide (in this experiment) seems to reduces the heat-holding effect of the atmosphere, and contributes to cooling of the atmosphere, compared to water vapor. Carbon dioxide contributes to a decreasing "greenhouse effect", and has a cooling effect on the Earth's atmospheric climate, as greenhouse gas.


The picture above shows the sun shining on the pet bottles. Below is the temperature in the two bottles.


Discussion:

The ideal gas law:

p * V = n * R * T
p = pressure (N / m²)
V = volume (m³)
n = amount of substance (number of moles; 1 mole = 6.02 * 10²³ pcs of molecules or atoms)
R = gas constant (8.3145 J / (mol * K))
T = absolute temperature (K (Kelvin))

In the experiment, p, V, R can be considered constant. This means that as the temperature rises, the number of molecules in the gas decreases. Similarly, as the temperature decreases, more molecules are allowed into the atmosphere of the bottle.

As the temperature rises, collisions of gas particles increase. The pressure is the same in both bottles, which means that there are fewer gas particles in bottle 1 (air) compared to bottle 2 (air and extra carbon dioxide). As bottle 2 has a lower temperature, more gas particles are allowed to be present in the atmosphere of the bottle.

An addition of carbon dioxide to the air causes some water vapor to condense into water. This can be seen if two pet bottles like bottle # 1 are set up (regular air in both). Let these bottles be for a while. Then in bottle 2 dissolve a little baking soda in the water and a little acetic acid is then poured in. The chemical reaction that takes place creates carbon dioxide which goes up in the atmosphere of the bottle according to the reaction:

Sodium hydrogen carbonate (baking soda) + acetic acid sodium acetate + water + carbon dioxide

NaHCO₃ + CH₃COOH CH₃COONa + H₂O + CO₂

This makes water vapor condense on the inside of the bottle (or disappear from the bottle). The heat-retaining property of the atmosphere ("greenhouse effect") decreases and the temperature drops. Carbon dioxide is a poorer greenhouse gas compared to water vapor, which means that an extra carbon dioxide addition to the earth's atmosphere lowers its temperature. Thus, it cannot be said that carbon dioxide would raise the temperature of the earth's atmosphere, since water vapor is not allowed in the atmosphere in the same amount as before the carbon dioxide addition.

The result is that Carbon Dioxide reduces the Earth's atmospheric current greenhouse effect and temperature.

Here are sources of error for this lab which must be taken into account. This laboratory does not show an absolute scenario for the greenhouse effect for the set up leaves some question marks and the interactions between the incoming gases are also complicated as they all have different properties.

That the cork is open with a little leakage:
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When the sun is on, gas from the bottle will leave the bottle. To say with this experiment that both bottles leak the same amount of gas - that would be a false statement. As the sun diminishes, outside air enters the bottle - a small "breath" of the bottle. On the other hand, under constant sunshine and rising temperatures, we can say that the flow of gas should be directed outward from the bottles.

The temperature sensor:
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This should be centered in the bottle and at the same height. Nor can this be guaranteed.

Convection:
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Bottle No. 2 with carbon dioxide may have two main convection cells (warmer air rises and colder drops). Carbon dioxide is a heavier (CO₂; 0.04%, 44 g/mol) gas than air containing mainly Nitrogen gas (N₂, 78%, 28 g/mol), Oxygen (O₂, 21%, 32 g/mol) and Argon (Ar, 1%, 40 g/mol). We assume that if the carbon dioxide content is quite high in the experiment, then carbon dioxide itself will have convection cells above the water surface. Remained air will have convection cells above these, and could also have a lower temperature. Now this experiment has also been done with the temperature sensors placed further down in the bottles as well, and the experiment has still shown that when the sun is on, bottle # 2 with a little added carbon dioxide has a lower temperature. We assume that the carbon dioxide is mixed in the experiment when its content is low and the lid is minimal-leakage-open. To minimiza low-temperature convection above the carbon dioxide convection cells, the aluminium foil would stop this, whereas the sun cannot shine throught the aluminium foil and heat the gas in the upper part of the bottle where the temperature sensor is.

Warning - there are errors in laboratory set ups that want to show that carbon dioxide raises atmospheric temperature.
- These are carried out today in schools.
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Several laboratory set-ups with a reference bottle have been set up in schools around the world to demonstrate the warming effect of carbon dioxide in an atmosphere. These experiments have been designed to show that carbon dioxide is responsible for the temperature rise between the years 1980 and 2000. Experiments have been set up to "prove" this. Here are the two most common laboratory setups that show this fraud.

IR lamp on reference pet bottle with air (1) and bottle with carbon dioxide (2):
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No water is in the bottles. There can be air in one bottle (1) and only carbon dioxide in bottle 2. The bottle with air then contains: 21% oxygen, 78% nitrogen, 1% Argon and minimal water vapor and carbon dioxide. The second bottle then contains pure carbon dioxide gas (100%). It goes without saying that the second bottle with carbon dioxide alone will show a higher temperature, since carbon dioxide is a greenhouse gas. The first bottle contains transparent gases (oxygen, nitrogen) that do not absorb solar radiation. In this way, one cannot set up an experiment as it goes without saying that a bottle with only greenhouse gas shows the highest temperature. With such an arrangement you want to show that a higher carbon dioxide atmosphere shows higher temperature.

E.g. these types of laboratory experiments:
https://www.rsc.org/Education/Teachers/Resources/jesei/co2green/home.htm
https://serc.carleton.edu/eslabs/weather/2d.html

In the reference bottle with ordinary air, the humidity will not increase significantly - which is normal in nature. More water vapor will not be supplied to the air, which means that hardly any extra water vapor can come to the rescue and help store the heat in the bottle's atmosphere.

IR lamp
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It is not possible to use an IR lamp because the IR lamp (short and long-wave heat radiation) is not the same as sunlight. The IR lamp heats the CO₂ gas directly (not "greenhouse effect") but cannot heat the air in the reference bottle. The sun is very far away.

Absence of water in the bottles
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70% of the earth is covered with water and water is found in soil and atmosphere. As the carbon dioxide content increases, water will condense. A good greenhouse gas (water) will be replaced by a bad greenhouse gas (carbon dioxide). The heat-retaining effect in the atmosphere gets worse and the "system" works to counteract a rise in temperature. In several school experiments, water is missing in the containers and the phase transitions of water are not taken into account.

Specific heat capacity
====================
To raise air 1 degree centigrade or Kelvin, 1.01 KJ / (kg * K) is needed. Here comes specific heat capacity for some gases.
Air       1.01 KJ / (kg * K)
CO₂     0.84 KJ / (kg * K)
Ar        0.52 KJ / (kg * K)
Cl₂       0.48 KJ / (kg * K)
CH₄      2.22 KJ / (kg * K)
H₂O      4,19 KJ / (kg * K)

Thus, less energy is needed to heat carbon dioxide one degree compared to air. From this, the temperature rises faster in carbon dioxide. The temperature rises even faster in chlorine gas.

Baking powder and acetic acid
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When using baking powder and acetic acid in water to produce carbon dioxide and using an excess of acetic acid. Here you can feel the smell in the bottle that its atmosphere is stinging. Acetic acid dissolves into the water vapor and we get dissolved acetic acid in the water vapor. In order for this experiment to be reasonably in accordance with nature, it must be calculated exactly how much acid is needed and exactly how much baking powder is needed to raise the carbon dioxide content to a certain level, e.g. 900 ppm or 1% or similar. Everything must react in the reaction and no extra acetic acid may be present, which dissolves in the water vapor and gives a pungent odor. This experiment Adrian Vance has done and reported in his book "Vapor Tiger". He shows that at 910 ppm carbon dioxide, the atmospheric temperature drops 1 degree compared to normal air.

Extra applicable dimensions of the universe:
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This experiment is three-dimensional with the room's three axes x, y, z and time. The universe is made up of more dimensions (10 in total) which also obviously affect the experiment, but much research remains.

Bottle Material
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This material can absorb some type of radiation - here may be a source of error.

Using tap water
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Tap water may contain e.g. chlorine gas or other additives that could affect the result. Chlorine gas has a lower specific heat capacity and could give a  temperature increase. Use mineral water instead.

Other
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We will update this lab further. If you have any comments, please enter them below in the comments field or send an email.

References
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https://principia-scientific.org/the-deliberately-false-greenhouse-gas-co2-experiment/
http://www.climatechangeeducation.org/hands-on/difficulties/heating_greenhouse_gases/
http://www.rsc.org/Education/Teachers/Resources/jesei/co2green/home.htm
https://serc.carleton.edu/eslabs/weather/2d.html
https://www.researchgate.net/figure/Greenhouse-Gas-Bottle-Demonstration-97-Bottles-with-CO2-and-air-are-radiated-and_fig77_324751934
http://chem-www4.ad.umu.se:8081/Skolkemi/Experiment/experiment.jsp?id=74
The book "Vapor Tiger" by Adrian Vance (recommended reading).
https://webapps.kemi.se/flodesanalyser/Amnesinformation/attiksyra_sv.htm

The search engine google shows in its search results only bottle labs which, on closer examination, mislead to give a definite view that extra carbon dioxide to the atmosphere raises the atmospheric temperature. In the experiment above, we show the opposite. Use the search engine e.g. Yahoo instead to compare.

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