Anonymous asked in Science & MathematicsBiology · 2 months ago

why is my teacher asking me take out 10ul of solution from my solution bottle for serial dilutions and not from my sample?

So I know why shes doing that. Its because the sample of mine is too concentrated however it doesnt make sense as thats not what I want to find out.

My experiment was that I will have e.coli bacteria in a spray bottle to spray onto a tile surface and too see how many bacteria were transferred. I then swabbed it onto a plate. My teacher told me as the plate had too many colonies id need to dilute it . So she said that I will go into the original spray bottle and scoop out 10ul using an inoculating loop. I am confused why. Am I not suppose to take out a scoop from my plate as thats what I want to dilute? is she assuming that when I sprayed my solution from the bottle, around 10ul was sprayed out onto the tile surface hence taking out 10ul from my solution bottle??

I want to know how much bacteria was sprayed out onto the tile surface and not how much was in the orginal solution?

Please could you provide an email address so I can contact and reply to your answers 

1 Answer

  • Jim
    Lv 7
    2 months ago

    They want you to use a 'known' amount from a 'known' solution...

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