34
The Greenhouse Effect
Subject: Biology/Environmental studies
Sensor: HiTemp temperature sensor
Aim:
To study the heating effect of Carbon Dioxide in relation to the earths atmosphere.
Overview:
Most students will have heard of the ‘greenhouse effect’. This investigation sets out to find out if high levels of Carbon Dioxide gas could cause a
‘warming up’ of the atmosphere. It makes use of readily available house hold chemicals and items such as small plastic bottles. By dropping an
Alka-seltzer
®
into one of the bottles, Carbon Dioxide will be produced inside the bottle and will simulate an increase in CO
2
levels within the bottles
‘atmosphere’. The other bottle will contain simply air and will remain as the constant in the experiment.
Equipment required:
LogIT Black Box
Temperature sensor (An additional sensor is preferable)
2 small bottles or flasks (the small drinks bottles are ideal)
Cotton wool
Alka-seltzer
®
or similar to produce the CO
2
gas
Lamp (100 watt bulb) to act as the sun
Hazards:
Students should be supervised at all times
Ensure the datalogger and lamp cannot come into contact with water or damp.
Always check your local regulations or the school advisory service such as CLEAPSS or SSERC for
guidance on the use of any hazardous material or source. Alka-seltzer
®
or similar can contain asprin.
Setup:
1. Pour the same amount of water into each bottle. We used 50ml in each bottle for this example.
2. Plug the Temperature sensors into Black Box and place in the top of the bottles. Make sure they are
near the top and not touching the sides and if using one sensor, make the position the same for both experiments.
3. Connect Black Box to the computer using the USB cable.
4. Seal one bottle using the cotton wool being careful to leave the temperature probe in place at the top of the bottle.
5. Have an Alka-seltzer
®
tablet ready for one of the bottles.
Note: The photo shows the Black Box and the two flasks during the experiment with the cotton wool sealing each of the flasks. The
use of the cotton wool offers a good insulated seal against heat loss and also allows any pressure created by the tablet to be safely vented.