The Earth's radiation budget and the Greenhouse Effect

Figure 1: Set-up for
Experiment 1:
L: lamp; T: thermometer 
A: water; C: carbon dioxide 
B: black cardboard   
I: heat insulation (cork plugs)
© 2004 Seesing, Tausch; Universität-Duisburg-Essen.

Figure 2: The Greenhouse Effect:
a large  part of the sunlight (I) reaching the earth (E) is absorbed, transformed into heat (Q) and the warmer  earth re-emits longwave infra-red heat radiation. Greenhouse gases (g) from the atmosphere (A) absorb this re-emitted heat almost entirely and send it partially back to Earth. These gases keep the heat in the lower atmosphere, like in a greenhouse.    (S: space)
© 2004 Seesing, Tausch; Universität-Duisburg-Essen, Duisburg.

Set up the experiment as shown in Figure 1. The experiment consists of a 300 W (tungsten) lamp, a glass container filled with water (1 cm high), a second glass container with black cardboard at the bottom and a temperature sensor in the air space in the lower glass container. 
Switch on the lamp, record the temperature every 30 seconds for 5 minutes and plot it on a graph.

T1

Carry out the experiment with a) air and b) carbon dioxide in the lower glass container.

T2

Repeat both experiments after replacing the black cardboard with aluminium foil.

temperature

background: black cardboard (A1)

background: aluminium foil (A2)

time [sec]

air

carbon dioxide

air

carbon dioxide

0

30

60

90

120

150

180

210

240

270

300

T3

Write down which part of the experiment E1 simulates which part of the environment by comparing Figures 1 and 2.

T4

Experiment E1 is a model experiment simulating the greenhouse effect. Why is it important to put cold water between the lamp and the gas space in the lower glass container? Tick the correct answer.

In the model experiment, the greenhouse effect is particularly obvious if there is black cardboard on the bottom of the gas space. You can also get satisfactory results using coloured cardboard, but not using aluminium foil. Why?

T7

Greenhouse gases in the lower atmosphere mean that the air next to the Earth's surface is, on average, 33 ^oC warmer than it would be without these gases.  20.6 ^oC of this temperature difference is due to the presence of water vapour, 7.2 ^oC is due to CO₂ and 2.4 ^oC is due to the presence of tropospheric ozone (O₃).  The air close to the ground contains 0.037% by volume of CO₂, but only about 40 ppb O₃. How many °C would the contribution of ozone be to the greenhouse effect if its contribution was proportional to its amount in the air?  Write down your calculation and result in the space below:

T8

In reality the contribution of ozone to the greenhouse effect is much higher than that calculated in T7. Why is this?