What is an apparatus consisting of a frame containing a number of parallel wires on which there are rows of beads which can be moved left and right?
Is in an abacus
What is the standard length of the bars in the uneven parallel bars or asymmetric bars, an artistic gymnastics apparatus used only by female gymnasts?
What medical apparatus is a large metal cylinder with a compressor that enables the internal air pressure to be changed rhythmically around 12 times per minute?
What is the name of a device, consisting essentially of two wires of different metals, whereby heat energy may be changed to electrical energy?