What You Need:
- Petri dish full of agar (available at a chemist)
- Cotton buds
- Some old newspaper
- Prepare your petri dish of agar. Agar is a gelatinous substance made up of sugar molecules.
- Using your cotton bud, swab a certain area of your house to collect a sample of bacteria.
- Rub the swab over the agar with a few gentle strokes before putting the lid of the petri dish back on and sealing the petri 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 petri dish and swab from under your fingernails or between your toes.
- Dispose of the bacteria by wrapping up the petri dish in old newspaper and placing it in the dustbin (don't open the lid).
The agar and warm conditions provide the ideal place for bacteria to grow. The microorganisms in the dish 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. Bacteria grows throughout the Earth - it grows in soil, radioactive waste, water, on plants and even on animals (humans included). Thankfully for us, our immune system usually does a great job of making bacteria harmless. Bacteria are a fascinating type of microorganism that play a huge role in our lives whether we like it or not. Try growing your own sample of bacteria while monitoring how it reproduces in a short span of time. Compare your original sample with others and get proof that bacteria truly are everywhere!