Special 11: Young Scientists Special

Air Date: April 26, 2008

In this episode, winners of Discovery’s “Young Scientist Challenge” competition tested environmental myths with the MythBusters team.

Do greenhouse gases really increase the amount of heat absorbed by air?

confirmed

Airtight containers containing added carbon dioxide or methane measured one degree centigrade hotter than containers with normal air after being heated by a hot lamp.

Are electric cars more sluggish than gasoline-powered cars?

busted

Adam, Jaime, and Brandon (a Young Scientist Challenge winner) built and electric go-kart using lithium iron phosphate batteries and tested it against a gas go-kart. Despite weighing twice as much as the gas go-kart, the electric go-kart performed equivalently. Then they went to a professional track and watched the KillaCycle, an electric drag motorcycle, race against a stock gas motorcycle. The gas motorcycle won by a slight margin. Next the MythBusters had an X1 electric sports car race against an F430 Ferrari, and while the Ferrari’s top speed was faster, the electric car accelerated faster and won in a drag race. Finally, they had electric X1 race against a FJR50 Forumla 3 race car. While the Formula 3 car easily beat the electric car, the electric car is considered a “street car”, not a race car, and it did well enough that they proclaimed electric cars to be anything but slow.

Do cows emit greenhouse gases that could potentially damage the environment?

confirmed

Cows themselves emit methane (mostly from belching, rather than flatulence) and their feces emit a significant amount of methane while rotting. Because there are so many cows, this methane contributes significantly to the amount of methane in Earth’s atmosphere.

Can cow manure be used to help the environment?

confirmed

The methane emitted from cow manure can be used to power combustion engines. The Young Scientists helped to collect cow manure and extract methane gas from it. Grant was able to use the methane gas to power a hand lawnmower. Also, the farm where they had collected cow manure from created 90% of its electricity from its own manure-powered generator.

13 Comments

  1. Kat says:

    The structure of H2O means ice has a higher volume than water. This would mean, if all the ice in the sea melted it would not cause any rise to the water level. The volume of the ice above the water at a low density would be equal to the melted water at high density.
    Does this mean global warming causing an increase to sea levels is a myth?

    • Dean says:

      “The structure of H2O means ice has a higher volume than water.”

      I’m having trouble understanding this statement.
      If you have a cubic foot of ice and a cubic foot of water, wouldn’t the voume of both be the same?

      I realize Kat is making some kind of point, and I’m not saying she’s incorrect, but I fail to understand her point due to the way she stated it.

      Can anyone please explain what it is she’s trying to convey?

      • MSpears says:

        When you freeze water, it expands. That’s her point. It still contains the same volume of water, but its molecules are organized in a different structure. Take a look at this web page for an explanation:

        http://www.iapws.org/faq1/freeze.htm

      • Ryan says:

        Dean is correct that the volumes stated would be the same, but Kat was referring to an equivalent mass. Normally as you heat a substance it expands, but because of the structure of H2O ice contracts as it melts. This means that 1kg of ice will have a lower volume than 1kg of water.

      • James says:

        when you freeze water it expands so it takes up more room.

  2. Will says:

    You are quite correct, melting sea ice has no impact on sea levels at all. However, it is melting of landlocked ice that will ultimately be the issue.

    At the moment the 20cm or so rise in sea levels since the 1880s is due to thermal expansion.

  3. Leon Stark says:

    Bovine, ovine, porcine, human, all fecal matter can be “fermented” into “natural gas”, and the remains processed into a fertilizer. It was normal for my wastewater plant to save money by using our own fuel, natural gas, to keep the digester warm.

    I had proposed the methane be used to power a generator for circulating the sludge, and the cooling water cycle as the heating for the sludge. The remaining gas could be compressed (the compressor powered off the methane powered generator) and sold to the local utility with the injection of the necessary ethyl mercaptan for odorant. Water and CO2 could be filtered off as it compresses. The facility could make plenty of money off the volume of natural gas they could provide the system, without drilling another well. They could also run cellulose to methane/ short-chain hydrocarbon/alcohol plants on the same principles if they had teh sense to. (Government in the business of carbon capture/reuse for the public good. (yeah, right!)

  4. Zeph says:

    Will is correct. If you read the news carefully, melting sea ice is described as an outcome of global warming, but not (by scientists) as affecting sea level. Sea level could be affected significant by melting of the Greenland ice sheet, or of Antarctica, which could dump more water into the ocean. But most of the rise so far is calculated to come from thermal expansion, which will also continue.

  5. felixnoir says:

    Trucks powered by methane from fertiliser weren’t uncommon in Britain in WW2 owing to food shortages, and you can find illustrations of them on the Web. I don’t know whether they are more environmental though.

  6. HoosierHawk says:

    The greenhouse experiment was very poorly designed, it was similiar to the “greenhouse in a bottle” experiments, two important controls are missing. 1st the glass used must be be transparent to all wavelengths of radiated light (IR) to avoid heating the glass, which leads conductive heating of the interior (heavy gases are more effective at conductive transfer). 2nd and more important, the containers can’t be sealed, there needs to be a pressure relief valve to maintain constant pressure. Because CO2 and methane are much heavier than air, the same temp will result in a higher pressure within the vessel. The higher pressure results in compression heating via the ideal gas law PV=nrT. The increase in temp is primarily due to the pressure rather than the IR absorbtion of the gases. That said, CO2 and Methane do absorb IR, but the experiment drastically distorts the effect.

  7. karl says:

    In the green house gas experiment, does anyone know HOW much CO2 was added? HOW much methane? To account for the 1 degree in temperature? Was it a doubling?

  8. Stu says:

    N2 and O2 are homonuclear diatomic molecules, they are transparent to infrared spectrum, they do not absorb infrared heat, they cannot be heated with an infrared heat lamp, and also they do not emit infrared, they cannot cool by the emissions of infrared radiation. O2 and N2 can only transfer heat by conduction.

  9. hailey says:

    i am doing a report on this

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