[MrForbes]

Start out the season by learning how to calculate the weight of parts, such as aluminum and steel and plastics and whatnot.

Aluminum weighs 0.10 pound per cubic inch.

Steel weighs 0.28 pounds per cubic inch.

Plastics mostly weigh about 0.05 pounds per cubic inch.

Weight the other parts like motors and transmissions and chains and stuff on a small scale...are there any in your science rooms? or the mail room?

Make a weight budget, starting with the chassis and electronics and pneumatics, the stuff that HAS to be on the robot. Then figure out how much weight you have left over for the rest of it, and if your design weighs too much, then you need to change your design before you start building it!