Here are the results of my simple multi-layer greenhouse experiment, conducted in December when the weather was hot and stable, not mild and rainy as it is now. The experimental setup is shown below, with two laboratory thermometers, and a mercury one to check. One sensor was attached to a 6in black tile sitting on the EPS box, the other on the glass surface. On top were up to 5 alternating layers of EPS and picture glass, as shown below.

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The temperatures are in C, and were measured by recording the maximum temperature over the period. As far as possible, I tried to obtain measurements on a clear calm day. The location is on the tropic of Capricorn in December, so the sun was virtually overhead.

Time	Layers	Tile	Glass

12:00	5	116	50
12:30	5	110	49
12:45	3	110	49
12:50	2	106.9	52.2
1:00	1	110.1	60.1
1:10	4	104.6	46.6
1:25	5	102.9	46.5

Below is a graph of the data above. Its fairly clear that the number of layers has very little effect on the temperature of the black tile. The temperature of the external glass layer does decrease however, with more layers. This I would think is due to the increased heat losses from the sides of the stack of alternating glass and EPS blocks.

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Once again, conducting this with precision outside is not possible without better equipment. As I reported with an earlier post, the temperature of the tile was beginning to melt the EPS foam.

The same result, of little change in the temperature of the tile with additional layers, was reported in a post by JQ Public:

My son and I repeated the experiment as mentioned and we the same results. We then used two glass jars, one as a control and one with water vapor and got the same results. We tried the two jar experiment again, but his time we stayed indoors and used a heat lamp and got the same results. In our fourth experiment we use one jar as a control and added vinegar and baking soda to the second jar to produce CO2. After and hour into the experiment we added even more vinegar and backing soda to create even more CO2 and yet again the temperature did not increase. The mean control jar temperature was 34.87 while the experimental jar was 35.43. The mean humidity for the control was <20% (we could not measure below 20%) and the mean humidity of the experimental jar was 42.73%.