schoolscienceproject.blogspot.in
Weather
frog
A tree frog made
of paper will climb up and down a ladder like a real weather frog and predict
the weather. Bend a 2f-inch-long strip of metal into a U-shape and bore through
it so that a sewing needle can be turned easily when inserted through the
holes. The needle is made able to grip by heating, and the frog, made from
green paper, is fixed on to it by a thin wire. Stick the metal strip firmly on
to the middle of the wall of a four-inch-high jar, and at the side a cardboard
ladder. Wind a thread round the needle, with a small counterweight at the end.
Stick a paper disk on a piece of plastic foil, and draw the other end of the
thread through the middle. The foil is stretched over the mouth of the jar so
as to be smooth and airtight, the thread is tightly knotted, and the hole
sealed. When the air pressure is high (fine weather) the plastic foil is
pressed inwards and the frog climbs up. When the pressure is low (bad weather)
the pressure on the foil is less and the frog climbs back down.
does it work
ReplyDeletehow do you make it?
ReplyDelete