KDS-1037
-
1
-
High Concentration
CO
2
Gas Sensor
Figure 1. High Concentration CO
2
Gas Sesor
Description
The ScienceCube CO
2
gas sensor is used to monitor gas concentration carbon dioxide in variety of
biology and chemistry experiments. It measures in range of 0 to 10 volume % (100,000 ppm) by
recording the amount of infrared radiation absorbed by carbon dioxide molecules.
The sensor uses a hot metal filament as an infrared source (IR), which is located at one end of the
sensor tube. At the other end of the sensor tube is an infrared sensor that measures how much
radiation gets through the sample without being absorbed by the carbon dioxide molecules. The
detector measures infrared radiation absorbed in the narrow band centered at 4.26
㎛
. The greater
concentration of the absorbing gas in the sampling tube, the less radiation will make it from the source
through the sensor tube to the IR detector.
The temperature increase in the infrared sensor produces a voltage that is amplified and read by an
interface.
CO
2
gas moves in and out of the sensor tube by diffusion through the six vent holes in the sensor
tube. When the sensor is collecting data, the IR source blinking on and off – it takes a new reading
about once every 3 second.
Suggested experiments
Measuring
CO
2
levels (respiration) from small animals and insects.
Monitoring
CO
2
changes in a plant terrarium during photorespiration and photosynthesis in
light/dark (combination with the light sensor).
Measuring
CO
2
levels during cellular respiration of peas or beans.
Monitoring production of CO
2
during chemical reactions
Na
2
CO
3
+ HCl
CO
2
+ H
2
O + NaCl
Monitoring CO2 consumption during chemical reactions:
2NaOH + CO
2
Na
2
CO
3
+ H
2
O
Important
: The sensor tube can never be placed into any liquids. The sensor is
intended only for measuring gaseous, not aqueous, CO
2
concentration.
