“You do not really understand something unless you can explain it to your grandmother.”

“If you can't explain it to a six year old, you don't understand it yourself.”

“Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.”

“Never memorize something that you can look up.”

“Many of the things you can count, don't count. Many of the things you can't count, really count.”

“Do you really believe that the moon isn’t there when nobody looks?”

“Gravitation cannot be held responsible for people falling in love. How on earth can you explain in terms of chemistry and physics so important a biological phenomenon as first love? Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.”