Table of contents for Greenhouse Experiment #3

  1. Global Warming Effect Experiment #3
  2. Simple multi-layer greenhouse

What affects global warming? We have been developing experiments to examine what affects greenhouse warming. To counter intuitive certitude, I have asked people to guess the results of simple experiments before they are done. Finally, we’ll evaluate the relevance to stratospheric and tropospheric forcing if at all.

This latest greenhouse experimental setup builds on the previous set. Here the arrangement is planar to the sun, in order to reduce some geometrical considerations. I have mounted it in EPS foam to insulate. There is a 6in black ceramic bathroom tile for a black body. Thin glass sheets (from cheap picture frames) may be arranged on top of an EPS frame about 1in in height. I also have a number of laboratory thermometers to record temperature more accurately. Here is a picture below.

The data below resulted from two sets of experiments. All temperatures are in degrees Celsius (C).

#3.1. conducted in the morning, I added up to five sheets of glass (layers), in contact with each other.
#3.2. mid morning, I recorded the temperatures of 0, 1 and 2 alternating air and glass levels. Layer 0 is the temperature of the black body with no glass sheet on top.

Bb: Temperature of the black tile
Go: Temperature of the outside surface of the glass
Ab: Temperature of the ambient air
G1: Temperature of the first glass layer (in a 2 layer setup)
OR: Over range reading


Layers Time Bb Go Ab
0 8:23 57.8
0 8:45 87.3 50.1 30.9
1 9:30 105.8 53.9 31
2 9:50 104.1 54.3 32.9
3 9:55 102.5 53.9 33.5
4 10:00 100.3 50.9 33
5 10:05 98.3 51.3 33


Levels Time Bb Go Ab
2 10:25 112 53 31
2 11:00 119.9 (OR) 58 32
2 11:10 112 93 (G1) 33
2 11:20 111 94 (G1) 33
1 11:30 109.8 60.7 33
1 11:45 106.3 57.1 33
0 12:00 75 33
0 12:15 69.8 34


Levels Time Bb Go Ab
1 12:30 90.3 53.5 34
1 12:45 95.1 52.5 34

The final set of readings after midday show a sharp decline in temperatures. This coincides with the appearance of high cloud that probably reduced incoming isolation.

The apparatus was oriented towards the sun in #3.1, and horizontal in #3.2.

The latitude was almost exactly on the Tropic of Capricorn, and the experiment conducted on Friday, Dec 4th, 2008.

The temperature of 119.9 is the peak temperature recorded before an out of range result was recorded. This was high enough to start to melt the EPS foam, as shown below. This surprises me for non-concentrated solar source, but was anticipated by Arthur Smith in a comment here.

I will develop greenhouse models using the data in subsequent posts this week. It strikes me there are a couple of possible greenhouse effect diagrams that could be drawn, and ways one might approach the issue of limits to the greenhouse effect.

I’ll probably put up a question asking people to guess the maximum temperature of the tile with five levels of alternating air and glass.

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