Übung

Siemens Stiftung

Detection of acids and bases using red cabbage juice

Matching exercise:
What substance can be added to change the color of red cabbage juice? What color does it turn, and what pH range does this color indicate?

Five everyday products are to be classified with respect to their properties as acidic (a), basic (b), or neutral (n). For this exercise, photos of the products as well as the associated indicator solutions (red cabbage juice) are to be matched to the corresponding position of the pH range.
The photos that have been matched can be dragged back or moved among the placeholders. The solution can be shown at any time during the exercise. The current status is preserved, which allows the exercise to be continued when the solution is hidden again. The matches can be evaluated by clicking the respective "Check? button. Any incorrect matches will be reset and can be matched again.

Information and ideas:
The students can test additional everyday products for their pH value using red cabbage juice as an indicator. For example, what makes red cabbage juice turn yellow, and what pH value does this color indicate?

Übung

Siemens Stiftung

Acids and bases in foods

Interactive exercise:
Which products are acidic, basic, or neutral or have an acidic, basic, or neutral reaction?

Twelve everyday products are to be classified with respect to their properties as acidic (a), basic (b), or neutral (n). The corresponding letters can be dragged to the right positions. The exercise can also be completed by hand on the interactive whiteboard.

Information and ideas:
The students can collect and classify other everyday products. For which of the three categories - acid, base, neutral - is it most difficult to find examples?