There was this biologist who was doing some experiments with frogs. He
was measuring just how far frogs could jump. So he puts a frog on a line and says "Jump frog, jump!". The frog jumps 2 feet. He writes in his lab book: 'Frog with 4 legs - jumps 2 feet'.
Next he chops off one of the legs and repeats the experiment. "Jump frog jump!" he says. The frog manages to jump 1.5 feet. So he writes in his lab book: 'Frog with 3 legs - jumps 1.5 feet'.
He chops off another and the frog only jumps 1 foot. He writes in his
book: 'Frog with 2 legs jumps 1 foot'.
He continues and removes yet another leg. " Jump frog jump!" and the
frog somehow jumps a half of a foot. So he writes in his lab book again:
'Frog with one leg - jumps 0.5 feet'.
Finally he chops off the last leg. He puts the frog on the line and
tells it to jump. "Jump frog, jump!". The frog doesn't move. "Jump
frog, jump!!!". Again the frog stays on the line. "Come on frog,
jump!". But to no avail.
The biologist finally writes in his book: 'Frog with no legs - goes deaf'
This is a very old frog joke. I found this version here: http://www.xs4all.nl/%7Ejcdverha/scijokes/4.html#old.scientists_5