VORTEX MIXING SCIENCE MODULE
PURPOSE
To show students vortex and mixing dynamics. For some reason kids from 5th grade to 9th grade are fascinated by vortexes.
MATERIALS
• Large beaker of water (at least 2 L)
• Magnetic stir plate with magnetic stirrer
• Blue or green food coloring
SETUP
Put water in beaker. Put stir bar directly on stir plate and explain there is another magnet underneath that is spinning and causes the stir bar to also spin. Scientists use stir plates to keep mixtures stirred for their reactions.
Place stir bar in beaker with water and slowly start stirrer. When system is stable speed up to maximum, ask students what they see. They will probably call it a tornado. Explain that like a tornado this is actually called a vortex. A vortex forms whenever there is a rapidly rotating fluid. Note the ropey appearance of the vortex.
Can the students think of any other vortexes they have seen? Possible answers could be tornados, hurricanes, river whirlpools, sink and bathtub drains, toilet flushing etc. Blender mixing is also an example.
When the vortex is stable carefully put a few drops of dark food coloring into the bottom of the vortex. Watch the dark area as it suddenly disperses throughout the beaker showing good mixing.
DISCUSSION
For a chemical reaction to take place good mixing has to happen first. Simplot uses large mixing tanks (million gallon) in its processes.
