A hydrogen atom lost its electron and went to the police station to file a missing electron report. He was questioned by the police: "Haven't you just misplaced it somewhere? Are you sure that your electron is really lost?"
"I'm positive." replied the atom.
The teacher of the earth science class was lecturing on map reading.
After explaining about latitude, longitude, degrees and minutes the teacher asked, "Suppose I asked you to meet me for lunch at 23 degrees, 4 minutes north latitude and 45 degrees, 15 minutes east longitude?"
After a confused silence, a voice volunteered, "I guess you'd be eating alone."
Don't LOOK at anything in a physics lab.
Don't TASTE anything in a chemistry lab.
Don't SMELL anything in a biology lab.
Don't TOUCH anything in a medical lab.
and, most importantly:
Don't LISTEN to anything in a philosophy department.
You enter the laboratory and see an experiment. How will you know which class is it?
If it's green and wiggles, it's biology.
If it stinks, it's chemistry.
If it doesn't work, it's physics.
What do you call a positively charged pussy-cat?