Question:
What are different types of stirrers used for and how can you visualize the flow or mixing?
You need:
- a hand drill or preferably a drill press
- 3D-printed stirrers
- a mixing vessel
- alginate or bubble tea pearls
- sugar
- brown rock candy
- red food coloring (preferably as a solid paste, e.g., icing pen)
- oil, preferably pumpkin seed oil (it’s very dark, making it particularly visible)
- water
You can print the stirrers with a 3D printer. For this, you will need our print files, which we have uploaded to the 3D printing platform printables.
Conducting the experiments:
Clamp the stirrers one by one into the drill and investigate the mixing behavior or mixing time for different stirring tasks. The stirring tasks we show in the following videos are:
- Suspending (distributing solid in liquid phase)
- Experiment 1a: Bubble tea pearls in water
- Experiment 1b: Bubble tea pearls in sugar solution (dissolve enough sugar until they float)
- Experiment 1c: Brown rock candy in sugar solution
- Homogenizing (dissolving two miscible phases into each other)
- Experiment 2: Food coloring in water
- Emulsifying (distributing two immiscible liquids into each other)
- Experiment 3: Oil in water
If you cannot conduct the experiments yourself, watch the videos in the explanation here on the website.