STORY LINKS: Oregano Against Fungi

Acidic vs. Alkaline Environments

An experiment with an egg in vinegar explains the effect of an acidic environment on materials. The activity introduces pupils to a biomimicry innovation that tackles the problem of food security and crop losses due to fungal diseases.

Age Group: 9-12 years

Duration: Experiment set-up 20 minutes, observation and evaluation of the experiment 15 minutes

Biomimicry Connection:

A biotechnology company has invented a new bio-fungicide in capsules that is easy to apply, and effective against fungal diseases. This nature inspired solution to minimize food waste was awarded the Ray of Hope Award that identifies the top nature-inspired startups in the world.

Activity Details:

Tools and Materials

  • Eggs
  • Vinegar
  • pH meter, pH indicator papers, pH scale
  • Jars
  • Acid and alkaline solution

Description

  1. Start by explaining the difference between acidic and alkaline environments. Ask pupils if they can name examples of something which is acidic or alkaline. How can they tell? Prepares one acidic (lemon, vinegar) and one alkaline (soap, soda) solution mixed with clean water in front of the pupils. Then demonstrates to how to measure pH using pH papers and a pH scale.
  2. Explain that different substances behave differently in acidic, neutral or alkaline environments. We will demonstrate this using eggs. 
  3. Put 3 identical eggs in three jars with three different solutions - a) vinegar; b) alkaline solution (dissolved soda for example); c) plain water. Ask pupils to guess what will happen to each egg by the next day.
  4. The next day, observe what has happened to each egg. Explain that vinegar is actually a dilute acid that has dissolved the basic building material of the egg shell - calcium carbonate.
  5. Asks pupils to look for examples of how this property of substances soluble in a certain (acidic or basic) environment can be used. For example, an egg immersed in vinegar for 24 hours will turn to rubbery and the shell dissolve, similar to limescale or lime plaster (effect of acid rain on buildings with lime plaster or on lime sculptures).
  6. Watch this video which explains how scientists have created a biofungicide contained in a capsule, that is only released when pH changes indicate the presence of moulds.