“What is mass?” I asked.

 

“Something that takes up space,” is the reply students often give.

 

“Well, consider a block of wood and a block of steel the same size. The steel has more mass. Therefore, your reply that mass is something that takes up space is wrong. Well, what is mass?”

 

I then tell them that when asked what is something in science, we must reply saying what do we do to measure it.

 

“How do we measure mass?”

 

“I do not know.”

 

“How do we measure your mass?” Note that the stress is on the person.

 

“By standing on a scale.”

 

“Good. Now you know that mass is something that we measure with a scale.”

 

There are some technical points that you can mention to advanced students.

 

SEE THE BOOK FOR MORE DETAILS.