One place where bacteria can be found is on your teeth. This is why it’s so important to brush well. Don’t believe me? Then this experiment is for you. You’ll need to gather your materials and make sure you have a toothbrush and microscope nearby.
This is important because prokaryotes are incredibly common and have a huge impact on our lives. You may already know some of the ways bacteria can be harmful to you, and this is certainly important information. Scientists have used knowledge of prokaryotes to create medications, vaccines, and healthy living habits that have led to a healthier life for billions of people.
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No, it should be fine either way.
I just went ahead and refrigerated it since it had beef broth. We can just heat it a bit to liquify and pour into the petrie dish. Sorry for the many questions and stream of thought.
Sandy
We made a homemade agar solution with the beef broth and gelatin. question: as this is over a five day timespan, do I refrigerate the beef broth solution or leave it out at room temp? I was not sure if the thickened gelatin solution would affect the bacteria results.
yeah I cant touch bleach it burns my skin super badly. this is a cool but gross exsperiment
😉
Thats gross :~)
Before getting to agar (like from here: http://www.hometrainingtools.com/agar-petri-dishes/c/193/), I have to say, “Wow!” What an awesome and creative application of the scientific method. Please share your data! As far as agar goes, you can use some alternatives to make your own. Basically, bacteria need food and something to grow in. You can use beef broth as the food and gelatin as the stuff to grow in. So, make some clear gelatin, but use beef broth in place of water. Also, don’t add any sugar. Your homemade agar will be thinner that what you’re used to working with, but it will work and will certainly save you money. Happy experimenting!
We have used 5 different toothpastes over the past 5 days and strange things are happening. We divided each dish in half and swabbed before brushing to put in one half of the dish and swabbed after brushing to put in the other half of the dish. 48 hours after each collection, ALL of the dishes are clean from colonies before and ALL of the dishes are growing numerous colonies on the after side. I’m photographing them daily to compare the days accurately, and the numbers are about the same, but the colonies are a little different. We couldn’t understand why colonies weren’t growing before we brushed our teeth but were after out teeth were supposed to be cleaner!
We called a friend of ours who is a periodontist, and he gave us a wonderful mini-lecture on how bacteria protects itself with a biofilm. After some discussion we also believe that our toothbrush might be introducing the bacteria. We are going to test several things. Is the toothpaste breaking down the biofilm and that is why so much bacteria is being released? We are going to use our current brush and swab before brushing, and swab after brushing without toothpaste. We are also going to pick a toothpaste we’ve already tested and swab before brushing, after brushing with a NEW toothbrush, and again after using Listerine. We are also going to wet our current toothbrush, let it set a minute, and spray the water into a petri dish by dragging our finger across the bristles. And for giggles, we are going to soak our toothbrush in Listerine, rinse it, and test it again in another dish.
Is there a recipe for agar that you recommend? I’m buying it from a science supply store, but it would be so much cheaper to make it myself. It’s the shipping costs that make it expensive!
The best thing to do is to pour a small amount of household bleach into the petri dish while holding the dish over the sink. It is a good idea to wear gloves and goggles while handling bleach, as splashing can lead to burns. The bleach will kill the bacteria. It is then safe to thoroughly wash the dish in warm water and use it again.
We are in the process of growing colonies in petrie dishes for this project. How do we properly dispose of this when we are done? We would like to keep the petrie dishes to use them again.