Science fair question regarding bacteria

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Momieto3
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Joined: Sun Dec 04, 2016 2:54 pm
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Science fair question regarding bacteria

Post by Momieto3 »

Hello

My science fair project is on different soaps and hand sanitizer and their affect on bacteria. I need help to determine what I should be seeing and if it worked or not. Are the colonies pretty obvious to the naked eye or can they only be seen under a microscope. I have looked up pictures online but don't know the if pictures are microscopic views. I also only had my dishes in about a 70 degree room which makes me wonder if it wasn't warm enough. Can you please tell me what i should be seeing?

Thank you
Morgan
donnahardy2
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Re: Science fair question regarding bacteria

Post by donnahardy2 »

Hi Morgan,

It sounds like you are working on a great project. The bacteria growing on the agar plates will be visible after the colonies form; you won't need a microscope. If you are incubating at 70 degrees F, it will take about two days for colonies to appear. Bacteria can grow at room temperature, but it just takes a little longer for them to appear. If there are no colonies after 3 days, then something is wrong.

Did you run a positive control with bacteria that you know would grow? What products are you using? If you are using hand sanitizers that contain ethanol, these may kill all of the bacteria.

Here is a link that contains information on microbiology techniques and includes a description of bacterial colonies. The information should be useful for your project.

https://www.sciencebuddies.org/science- ... nces.shtml

Please post again if you need more help. If you have no bacteria growth at all, then you need to figure out what happened before you try again. Or, if you are out of time and your project is due, you will need to explain your results.

Donna Hardy
Momieto3
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Joined: Sun Dec 04, 2016 2:54 pm
Occupation: Parent

Re: Science fair question regarding bacteria

Post by Momieto3 »

Doona,
Thank you so much for your quick reply. The link is very helpful. I did use a control, 2 soaps, 1 antibacterial soap, and 3 different hand sanitizers. And also one with just plain blotter paper. All the Bacteria is clear to yellow color/transparent. It's really hard to distinguish if it is a bacteria colony or just the agar. I have noted everything I can see and I am going to do the same experiment again just to see if I get the same results or if something went wrong. I appreciate your help! Thank you.
Morgan
Momieto3
Posts: 4
Joined: Sun Dec 04, 2016 2:54 pm
Occupation: Parent

Re: Science fair question regarding bacteria

Post by Momieto3 »

Hello

I am writing again with another question about my science fair project. I am testing different soaps, hand sanitizer and antibacterial soap to see which is better. My experiment is using blotter paper. After noting all changes up to 7 days of my project, I want to make sure I am understanding the results correctly. Most of the Petri dishes look a lot alike but there are a couple that are slightly different. The difference is around the blotter appear there seems to be none or very little colonies around the paper compared to the others. Is this the area I should be focusing on? Around the blotter paper? Or should I be focusing on the entire kerri dish where I steamed the agar?
Momieto3
Posts: 4
Joined: Sun Dec 04, 2016 2:54 pm
Occupation: Parent

Re: Science fair question regarding bacteria

Post by Momieto3 »

Hello

I am doing science fair project to test effectiveness of different soaps, antibacterial and hand sanitizers. I used blotter paper and agar with petri dishes. I did the experiment twice just to make sure I didn't do anything wrong. But now I am ready to make a chart/graph with my results. I want to make sure I understand the results correctly. The area that I should be focusing on is around the edges of the blotter paper, is that right? The blotter paper is what had the soap or sanitizer on it, so that is where I would see a difference if there is one. Can you tell me if that is right.

Thank you for your help again
Morgan
ajcourtney
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Re: Science fair question regarding bacteria

Post by ajcourtney »

Hello there!

Check out this link about the zone of inhibition. I hope this helps!
http://microchemlab.com/test/zone-inhib ... l-activity
-AJ
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