Comments on: Special 11: Young Scientists Special

By: Stu

Stu — Mon, 07 May 2012 20:32:14 +0000

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.

By: karl

karl — Tue, 11 Oct 2011 21:23:28 +0000

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?

By: HoosierHawk

HoosierHawk — Fri, 30 Sep 2011 00:49:18 +0000

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.

By: Ryan

Ryan — Fri, 02 Sep 2011 17:29:13 +0000

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.

By: MSpears

MSpears — Thu, 25 Aug 2011 14:49:13 +0000

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

By: Dean

Dean — Sun, 29 May 2011 09:50:48 +0000

“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?

By: felixnoir

felixnoir — Sat, 14 May 2011 22:50:03 +0000

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.

By: Zeph

Zeph — Tue, 28 Dec 2010 02:46:28 +0000

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.

By: Leon Stark

Leon Stark — Sat, 26 Dec 2009 04:05:08 +0000

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!)

By: Will

Will — Sat, 24 Oct 2009 10:00:15 +0000

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.