Travelling Waves (B+25)

  B+25+0 Transverse wave model, hand-cranked.
  B+25+1 Transverse 3-dimensional wave model, hand-cranked.
  B+25+5 Longitudinal wave model, hand-cranked.
  B+25+10 Rubber rope stretched across front of room.
  B+25+15 Brass spring on white plastic sheet.
  B+25+20 Suspended slinky on threads for compression wave.
  B+25+25 Mechanical water wave model, hand-cranked.
  B+25+27Hand held long torsional wave device
  B+25+30 Torsional wave device, large or small.