This is setup at the beginning of class. Students are asked to make an observation, without saying anything.They then share their observations. Then I ask for inferences. This conversation leads to a discussion about force fields and the magnets. After they are set up. GENTLY have a student wiggle one magnet and the others wiggle too.
The textured surface is a non-slip rubber mat. It is usually put under throw rugs to keep them from slipping. The donut magnet is a ceramic permanent magnet, "Ceramic Ring, Pkg/2 3 7/8 inches diameter x 5/16 inches " from http://www.scientificsonline.com/ceramic-permanent-magnets.html it is $7.00 + shipping (April, 2012, prices.) The four smaller ceramic magnets are from Lowes or Radioshack. They are about 3/8” x 7/8” x 1.5” in size and cost about “$2.00 each, (April, 2012, prices.)