Activities | Chemistry and Biotechnology
Coloured foam
Materials:
- Baking soda
- Vinegar
- 2 disposable cups
- Powder soap or detergent
- Water
- 4-colour food colourings
Preparation:
1. In one of the cups, dissolve the baking soda in water. It is not necessary to add too much water, only 1/4 of the cup so that the baking soda dissolves.
2. Add your favourite food colouring. Use a different cup for each colouring.
3. In another cup put the vinegar and add the detergent carefully so as not to form too much foam.
- Next, in a larger bowl, mix the contents of the two cups and watch the foam grow!
Explanation:
A particle in the vinegar acid (acetic acid proton) reacts with the baking soda (more specifically with the hydrogen carbonate ion). This reaction releases a gas (carbon dioxide) which, when mixed with the detergent, produces the foam that overflows the containers.
The main objective of this experiment is to show that effervescence is a reaction during which a gas is released and this gas produces coloured foam when in contact with the powder soap.
Activity instructors: Isabel Silva, Sofia Duarte (Lab.EQ - Chemical Engineering Lab)
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