Poly Density Bottle @Teachersource

Uploaded April 2011 | Updated September 2026, 2 weeks ago

When the 1L bottle is shaken, blue and white beads mix as expected. However, when allowed to settle, the beads separate, white at the top and blue at the bottom. Then, the two separated colored beads slowly come together in the center of the liquid. Available from Educational Innovations, Inc. at teachersource.com/product/poly-density-kit/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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