alekssinel Posted July 13, 2021 Report Share Posted July 13, 2021 (edited) Hey Everyone I'm doing my Biology IA over the summer, and i was wondering if there is a standard uncertainty value for absorbance (when using a colorimeter)? Absorbance doesn't really have units (only 'absorbance units') so i'm unsure. Our colorimeter didn't specify if there was an uncertainty, and all the info online about it (Vernier) doesn't say anything. I can't message my teacher about it because she left and we're getting a new one next year :/ So, if anyone did a colorimetry IA or prac, is there an uncertainty for absorbance? Thanks!! Edited July 13, 2021 by alekssinel Reply Link to post Share on other sites More sharing options...
bigcauliflower Posted July 16, 2021 Report Share Posted July 16, 2021 On 7/13/2021 at 4:46 PM, alekssinel said: Hey Everyone I'm doing my Biology IA over the summer, and i was wondering if there is a standard uncertainty value for absorbance (when using a colorimeter)? Absorbance doesn't really have units (only 'absorbance units') so i'm unsure. Our colorimeter didn't specify if there was an uncertainty, and all the info online about it (Vernier) doesn't say anything. I can't message my teacher about it because she left and we're getting a new one next year 😕 So, if anyone did a colorimetry IA or prac, is there an uncertainty for absorbance? Thanks!! Apparatus like those usually express values in percentage %, it is very common to have an uncertainty anywhere from 0.5% to 5%. It is usually stated in the user manual or else please message me of the brand which you are using. Reply Link to post Share on other sites More sharing options...
alekssinel Posted July 19, 2021 Author Report Share Posted July 19, 2021 On 7/17/2021 at 12:31 AM, bigcauliflower said: Apparatus like those usually express values in percentage %, it is very common to have an uncertainty anywhere from 0.5% to 5%. It is usually stated in the user manual or else please message me of the brand which you are using. Thank you for replying. Unfortunately the user manuals online do not state the uncertainty for this colorimeter, or any, in fact. I had used the Synaptic Sensors, LLC colorimeter (http://www.synapticsensors.com/colorimeter-for-labnavigators-plug-play/). It does say that the resolution is 0.035 %T, so i was thinking maybe that is somehow significant? Not entirely sure. And regardless, i would need absorbance uncertainty, and not transmittance. Reply Link to post Share on other sites More sharing options...
bigcauliflower Posted July 19, 2021 Report Share Posted July 19, 2021 2 hours ago, alekssinel said: Thank you for replying. Unfortunately the user manuals online do not state the uncertainty for this colorimeter, or any, in fact. I had used the Synaptic Sensors, LLC colorimeter (http://www.synapticsensors.com/colorimeter-for-labnavigators-plug-play/). It does say that the resolution is 0.035 %T, so i was thinking maybe that is somehow significant? Not entirely sure. And regardless, i would need absorbance uncertainty, and not transmittance. if it does not specifically say, then what you do is divide the smallest expressed value by 2. For example, a measurement cylinder which uses the measurement unit of 1 ml (seen by the difference between two values) would be divided by 2 = 0.05ml. But I saw that yours say that the smallest value is 0.05, so I would use the value of 0.025. Reply Link to post Share on other sites More sharing options...
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