JAMB - Physics (1991 - No. 12)
In which of the following is surface tension important?
the floating of a ship in water
the floating of a dry needle in water
the floating of a baloon in air
the diffusion of sugar solution across a membrane
Explicação
A carefully placed small needle can be made to float on the surface of water even though it is several times as dense as water. If the surface is agitated to break up the surface tension, then needle will quickly sink.