Experiment: The Color Sensor – How a Biosensor Detects Substances

21.02.2025

Materials:

• Red cabbage or turmeric (as a natural indicator)
• Vinegar (acid)
• Baking soda or baking powder (base)
• Water
• Two glasses
• Tea filter or coffee filter

Instructions:

1. Prepare the indicator solution:
• Chop a few leaves of red cabbage and pour hot water over them. Wait 10–15 minutes until the water turns dark blue or purple.
• Alternatively, mix some turmeric powder with water.
• Filter the solution so that only the liquid remains.
2. Prepare the “biosensor”:
• Divide the indicator liquid into two glasses.
• Add vinegar to the first glass and baking soda solution to the second.
3. Observe:
• The red cabbage juice turns red with vinegar and green or blue with baking soda.
• The turmeric solution stays yellow with vinegar but turns orange or reddish with baking soda.

Explanation:
Real DNA biosensors detect specific substances and send a signal. Here, the color change shows that the chemical environment has changed – just like a biosensor that reacts to a specific substance!

With this experiment, you can understand how sensors work in biotechnology!