Experiment for kids – Grow harmless microbes


In this experiment for kids, we will see how to grow a small culture of harmless microbes in the kitchen. Pasteur discovered the existence of microbes in 1859. This discovery hailed the beginning of modern biology and effective remedies. Microbes are tiny microscopic organisms that are invisible to the naked eye. Some are beneficial and others are harmful.

Equipment for the experiment for kids:

  • 4 small plates
  • Cling film
  • Half a litre of rice cooking water
  • Salt
  • Gelatine
  • Half a cube of beef bouillon
  1. The first step is to prepare the environment in which the microbes will develop. Mix together half a litre of rice cooking water, the half bouillon cube, a pinch of salt and the gelatine.
  2. Divide the mixture onto the four plates and cover immediately with cling film. Leave to cool.
  3. Distribute 3 of the plates into different rooms of the house. This step is so that we can capture microbes that are in the surrounding air. Lift the film and allow the microbes to settle for 15 minutes. Leave the fourth plate with the film covering it. This will allow you to compare the results.
  4. Re-cover the plates with the film. Place in a warm place, for example, next to a radiator.
  5. Approximately 72 hours later, you will be able to see dark spots. These are the microbes that have developed. The plate that was kept covered is clear.

Explanation of this experiment for kids:

Like all living things, microbes need an environment to develop, that is to say, a comfortable temperature and nutrients. Yes, microbes feed.

If microbes are microscopic, why are they visible on the plates? Simply because we are not observing one microbe, but a whole colony. This high concentration of individual microbes makes them visible to the naked eye.

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