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Ask HN: Simple experiments to demonstrate the “greenhouse effect”

2 points by perpetualcrayon ↗ HN
My thinking on the subject of global warming recently has been like this:

It seems there is too much "special interest" skepticism in the way on both sides of the argument (understatement of the century?) to think any individual is going to feel they can make any progress by simply arguing the points / counter-points of the argument. It just makes people angry and is almost always counter-productive.

If one wanted to demonstrate in a cheap, relatively quick, imperfect but sufficient fashion that the "greenhouse effect" is a real thing, how would they go about doing that?

I'm thinking if elementary, middle, or high schools (after school programs?) could reproduce this simple experiment for small classes it could be a catalyst for changing the opinions of the masses on climate change.

PS. My hope is this comment thread can remain civil. ;)

5 comments

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pkt_nspktr
Here's my gedanken experiment (caveat: I'm not an environmental scientist or engineer!): suppose you have a large box (closed system) with a large number of light bulb sockets and an infinite power source. Let a light bulb represent the amount of energy required by a person (i.e. home electricity, gasoline for travel, food for consumption, etc.). As the number of light bulbs increase within the box, the temperature rises. Regardless of other factors (e.g., CO2 emissions, energy sources) the transformation of fuel to energy, and energy to work, is not 100% and so there will always be waste heat produced.

One may use more energy efficient bulbs to maintain (or slightly decrease) the temperature within the box while increasing the number of bulbs. But savings from energy efficiency will be quickly spent as we add additional bulbs to the box.

I'll let the reader (experimenter?) draw her own conclusions about this thought exercise.

tlb
The effect of all our waste heat on earth's climate is insignificant -- thousandths of a degree. The greenhouse effect works in a completely different way, by CO2 reflecting infrared radiation that would otherwise transfer heat from the surface into space.

It's dangerous to promote incorrect ideas about how global warming works. For example, if global warming was just a problem of waste heat, we could shut everything off and things would be back to normal in a few days. But because it's caused by CO2 accumulating in the atmosphere, once we release CO2 it takes a long time (hundreds of years) for it to be re-absorbed by forests. People who saw these light-bulbs in a box might think that a quick solution is possible if warming gets out of hand.

grizzles
> If global warming was just a problem of waste heat, we could shut everything off and things would be back to normal in a few days.

Regardless of cause, the law of conservation of energy says otherwise. Also this isn't the type of law that congress can change.

titojankowski
Climate change must be felt to be understood.

Depends what you're trying to demonstrate. I think the greenhouse effect is cool. Carbon dioxide is useful, it's just not in the right place.

How might we build a bunch of rooms with different amounts of carbon dioxide in them. And big lamps. In the rooms with low carbon dioxide, it's cool. With rooms with lots of carbon dioxide, it getd hotter and hotter.

Even a simple physicics simulator app would be cool, different ppm of carbon dioxide, and showing the change/temperature stability. I remember fooling around with a physics simulator as a kid, springs and boxes, then you hit go and they all move with gravity. Power it with data from the open climate API at http://carbondoomsday.com

Keep the ideas coming!

mapster
i imagine you need to convey a few important things: (1) effect of CO2 on atmosphere per what tlb said below and (2) magnitude of CO2 emissions (like telling people 1 part per billion is a eyedrop of water into a swimming pool, etc.)