Science Buddies: "Ask an Expert"

Hi, so I am using this project idea and making it my own. On the material list it says 8 plus three next to the Glucose strips. What does that mean? https://www.sciencebuddies.org/science- ... #materials

Hi Samira1231 and welcome to Science Buddies!

To your question: you set up 8 glucose strips to develop a standard range of outcomes (i.e., color scales). In addition, for each experimental food or drink item you run, you run three additional strips, to get replicate samples (i.e., three replicates!).
You can see this by looking at the experimental protocol in greater detail.

So for example, if you ran 7 different foods/drinks you would have: 8 + 3x7 = 8 + 21 = 29 strips needed. But in fact, you may want to just have extra strips beyond that in case something gets messed up or you want to run additional tests you may not have initially thought of, etc.

Hope it helps, and feel free to send more questions as you develop your experiment.

BenG

What do you mean by set up 8 strips? My plan was to have 5 trials were I get like for example Apple juice and I use the glucose strip to find out the glucose concentration. Do I use one glucose strip or eight? I didn't understand that part? Thank you!

The eight strips are reference strips for the eight standard solutions, that are used as your controls (4%, 2%, 1%, 0.5%, 0.25%, 0.125%, and 0.0625% dilution series and a 0% negative control). This is described in the procedure page of the experiment:
https://www.sciencebuddies.org/science- ... #procedure

In your example, you would use one strip for each apple juice sample (i.e., 5 strips), but you also need eight additional strips to dip in each of the eight control solutions. Thus a total of 5 + 8 = 13 strips. The reason for this is that each of the eight additional strips is dipped into a control glucose solution with a known amount of glucose. Then you look at the color result for those. then you compare the results from your five trials to the eight ~known~ control strips, to estimate the glucose concentration.

Read through the procedure page a few times and try to understand everything - I think it will help.

BenG

Oh okay that makes sense now! Thank you!