What you'll need:
- Petrie dish of agar
- Cotton buds
- Some old newspaper (to wrap petrie dish when disposing)
Instructions:
- Prepare your petrie dish of agar.
- Using your cotton bud, swab a certain area of your house (i.e. collect a sample by rubbing the cotton bud on a surface of your choice).
- Rub the swab over the agar with a few gentle strokes before putting the lid back on and sealing the petrie dish.
- Allow the dish to sit in a warm area for 2 or 3 days.
- Check the growth of the bacteria each day by making an observational drawing and describing the changes.
- Try repeating the process with a new petrie dish and swab from under your finger nails or between your toes.
- Dispose of the bacteria by wrapping up the petrie dish in old newspaper and placing in the rubbish (don't open the lid).
What's happening?
The agar plate and warm conditions provide the ideal place for bacteria to grow. The microorganisms on the plate will grow into individual colonies, each a clone of the original. The bacteria you obtained with the cotton bud grows steadily, becoming visible with the naked eye in a relatively short time. Different samples produce different results, what happened when you took a swab sample from your own body?
You will find bacteria throughout the Earth, it grows in soil, radioactive waste, water, on plants and even animals too (humans included). Thankfully for us, our immune system usually does a great job of making bacteria harmless.
