Science Buddies: "Ask an Expert"

Hi, I had an online bacteria growth lab from summer class, however I don't know how to deal with it. I tend to compare bottled water or tap water has more bacteria? I don't know how to write the hypothesis, procedure and also variables for this. Please, help me!

What is the most effective in killing Staphylococcus Aurenus?

Household Bleach, Anti-Bacteria Soap or Household disinfectants? and Why?

Moderator Note: I've merged your 2 posts so the experts can see that they are related. Thank you.

Hi there,

There's a lot to be done, so let's take this step by step! First, in case you haven't seen it, I'll link our Project Guide here, which has a bunch of resources that should help you get oriented on how to tackle hypotheses and procedures: https://www.sciencebuddies.org/science- ... ience-fair

It sounds like you already have a research question: "What is the most effective in killing Staphylococcus Aureus?"

From here, you'll want to do a little background research and form a hypothesis about which of the three you listed will actually be most effective. You could start by finding how each of the disinfectant items work. (This is also your independent variable: you are varying which disinfectant to use.)

For procedures, you'll want to think about how you're going to measure "most effective." Consider what materials you have access to when thinking about procedure. Background research can help here, too: how have other scientists measured effectiveness of anti-bacterial disinfectants? (One common method is disk diffusion: https://en.wikipedia.org/wiki/Disk_diffusion_test)

The final procedure determines your dependent variable—what you will physically "measure" to collect as data.

Hope that helps. As I said, start developing this project one step at a time, and come back with more questions.