Show A soapsuds surprise here Is an experiment with soapsuds in which there Is no bloing blow ins of 0 bubbles fasten two knitting needles needle or other small rods together mith alth threads of equal length so as to form a rectangular frame A third thread attached to the upper rod enables enable 3 you to hold bold up the frame without touching it it plunge the frame into strong soapsuds and lift it out slowly by this third thread you find the frame filled by a transparent liquid film like a pane of glass break this film dim and attach to the vertical threads about one third of their length fro from in the bottom the ends of another thread which Is no longer than the knitting Ini ting needle so mat it bans bangs do in a curve and to the middle of this thread fasten still another thread by one oneena on elend end leaving the other end han arg don do now di dip the lie frame again in the a soapsuds and lift it out the last t two lastic veo threads mill bill appear as irregular Ir regula lines n s embedded in tile the film of liquid ur break oak the iho lower part of the film and ou oil will mill see the upper part contract drawing the loose thread up with it lito the form of a circular arch now talie take hot hold of the tree free langing lanel ng thread below tile the lower rod and pull downward the single arch becomes a double arch but its ormer former shape as soon boon as ai ou release the bauling thread these experiments which might bo be frame for fop the films varied in many ways show allow that the th liquid film Is like ilka a stretched elastic clastic membrane or sheet of 0 india rubber it always makes itself as small as possible as the last experiment pro proves ea and if stretched out by force it contracts again as soon as the force ceases to act it affords therefore an interesting example of the surface tension possessed by liquids the film lias has two parallel surfaces and their tensions act together |