There is growing consensus amongst scientists that the world is going through a period of rapid climatic change, driven at least partly as a result of anthropogenic production of greenhouse gases such as CO 2 (Maslin M 2004).

This is now something that can be achieved, at a realistic cost, in the school classroom, due to the production of a gaseous CO 2 sensor by the USA based company Vernier (distributed in UK by Instruments Direct Ltd). This paper concerns the opposite – making an otherwise invisible gas, carbon dioxide, visible (at least in a quantitative sense). Most people have fantasized about what it would be like to be invisible to others.

A simple equation for converting rates of change of gaseous CO 2 concentration change into energy or glucose equivalents is suggested. Suggestions are made for taking measurements in the field, as well as demonstrations and project work in the school laboratory. This paper introduces the use of a gaseous CO 2 sensor and data logging equipment, for a variety of purposes in the school laboratory, including measurements of respiratory and photosynthetic rates of animals, plants and microbes. School Science Review (the ASE’s journal for science education 11 – 19), ASE, March 2006, 87 (320) By positioning the measuring hose correctly, you can also make a correct measurement at different heights to chart all risks.Reprinted with permission from the author Roger Delpech and the publication School Science Review. This allows you to make an appropriate risk analysis and make the right strategy and PPE choices based on the measurement results. This means that you can take a measurement from a safe distance so you have an idea of which gases will be present in which concentration before you are exposed to this environment. A sampling hose may be connected to extend the reach. This means that the device is constantly drawing in gases. Pumped instruments are equipped with a built-in sampling pump. Since there is no forced flow of the gas to be measured, this device is not suitable for taking measurements remotely, but they do accurately identify what’s present in a given location. This also means that a diffusion gas detection device is only able to measure the concentration of gases at the location where the device is located. Diffusion means proportional spread of molecules over the available space (from high concentration to low concentration). The sensor is exposed to the ambient air and will measure the gas by means of the diffusion principle.

For more accurate detection, calibration around the concentration of interest is recommended.Ī diffusion gas detection device works, as the name suggests, on the diffusion principle. Quoted accuracy achievable up to 2,000 ppm. All specifications shown are at the calibration point and under the same environmental conditions. *** Specifications are based on calibration of isobutylene at 20 ° C and 1000 mBar. ** Maximum reading is obtained with some analytes such as ethanol. Li-ion: life up to 24 hours, charge time 6.5 hoursĪlkaline: 3 x AA, typically 8.5 hours lifeĢ point and 3 point calibration (via calibration kit accessory)įlashing LEDs Amber (low alarm) Red (high alarm)ġ0.6 eV: -20 to 60 ☌, -4 to 140 ☏ (non Intrinsically Safe)ġ0.6 eV: 15 to +45 ☌ / +5 to 113 ☏ (Intrinsically Safe environment)ġ1.7 eV: 15 to +45 ☌ / +5 to 113 ☏ (Intrinsically Safe environment)ĮMC tested to EN61326-1:2006, EN50270:2006 & CFR 47:2008 Class A Tamb = – 15 ☌ ≤Ta ≤ +45 ☌ (with alkaline battery pack)ģ193491 conforms to UL Std. Tamb = – 15 ☌ ≤Ta ≤ +45 ☌ (with lithium ion battery pack) 10.6 eV: ± 5 % display reading ± 1 digit***

30 ppm in logger pro picture