# Glucose concentration vs absorbance watch

1. Im new to all of this and I have been set to draw a graph. I have the concentration of glucose and I also have the absorbance data. I just do not know where to start and what data to put on the x or y axis. I don't even know if there are calculations involved. Can someone explain it to me or help me?
2. Concentration on the x axis (because you KNEW the concentration - right?), absorbance on the y axis. Usually as a percentage. The absorbance should increase with concentration.
3. what do you mean by as a percentage Do i need to do any equations? Sorry I'm so confused and stressed out
4. No you don't need to do an equation as far as I am aware - what did you do in class? Were you told to do an equation? Do you even know the point of the experiment?
5. (Original post by Strawberry Blue)
Im new to all of this and I have been set to draw a graph. I have the concentration of glucose and I also have the absorbance data. I just do not know where to start and what data to put on the x or y axis. I don't even know if there are calculations involved. Can someone explain it to me or help me?
Here's one I made earlier. By earlier I mean about 3 years ago, and badly. This is just to give you an idea of how it should look.

Attachment 191146

It's not complete - you need to label the axes. Glucose concentration on the X axis and absorbance up the side on the Y. (You always put the variable that you know/are controlling along the bottom). Plot all your points in two columns on Microsoft Excel - you should use a tutorial if you don't know how to do this. I generally just play about with it for a while until it works. I hate Excel. Anyway I've also put on a "trendline" - a line of best fit. You can just right click your existing graph and select the option to do that. The numbers in the top right hand corner is the equation of the best fit line. You may or may not need that. Generally you would use that to find out an unknown - like if you knew the absorbance of your unknown sample and you wanted to find out what the concentration of it was. The "R-squared value" below it shows how close your actual line was to the trendline. The closer to 1 the better. A score of 1 would mean your actual line you generated from your results was identical to the trendline, i.e. perfectly linear. Ask you can see, mine was pretty bad.
6. (Original post by LinzyLoo)
Here's one I made earlier. By earlier I mean about 3 years ago, and badly. This is just to give you an idea of how it should look.

Attachment 191146

It's not complete - you need to label the axes. Glucose concentration on the X axis and absorbance up the side on the Y. (You always put the variable that you know/are controlling along the bottom). Plot all your points in two columns on Microsoft Excel - you should use a tutorial if you don't know how to do this. I generally just play about with it for a while until it works. I hate Excel. Anyway I've also put on a "trendline" - a line of best fit. You can just right click your existing graph and select the option to do that. The numbers in the top right hand corner is the equation of the best fit line. You may or may not need that. Generally you would use that to find out an unknown - like if you knew the absorbance of your unknown sample and you wanted to find out what the concentration of it was. The "R-squared value" below it shows how close your actual line was to the trendline. The closer to 1 the better. A score of 1 would mean your actual line you generated from your results was identical to the trendline, i.e. perfectly linear. Ask you can see, mine was pretty bad.

Thank you so much for explaining it but I can't open the attachment! Is there any way you can send it me so I can open it? Im so grateful for your help!
7. (Original post by Strawberry Blue)
Thank you so much for explaining it but I can't open the attachment! Is there any way you can send it me so I can open it? Im so grateful for your help!
Yeah sure I'll PM you it

Edit: Negged for helping someone?!

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