ZigZag Density Tumbler @Teachersource

Uploaded March 2017 | Updated September 2026, 2 weeks ago

This elegant desk "toy" offers a hypnotizing demonstration of surface tension, density and insolubility. Turn the clear tumbler over and watch as two different colors of droplets float down in relaxing zigzag patterns. Great as a discussion or inquiry starter. How many liquids does the tumbler contain? What can you infer about the density of each liquid? What causes the difference in the size or speed of the droplets? How does static electricity affect the liquids? It's a soothing demonstration of potential and kinetic energy in action. Available at teachersource.com/product/zigzag-density-tumbler/density

$Disappearing Beaker This clear beaker has no markings and bends light to the same degree as cooking oil. The borosilicate glass and the oil have roughly the same index of refraction. When this beaker is immersed into a container of oil, the beaker becomes invisible. Package includes the beaker and instructions. You supply the outer container which can be any clear, colorless container with at least a 4 inch opening. Drop pieces of broken borosilicate glass into a large container of oil and watch the pieces disappear. Then, using tongs, reach in and remove a previously hidden, unbroken beaker. Ask students to explain. Available at https://www.teachersource.com/product/the-disappearing-beaker/light-illusions$

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