Ask A Scientist Chemistry Archive

Question:
My name is Joey and I am using my brother's IDF. I am in 4th grade and
my science teacher just taught us about density. I don't understand
it. I have a test this Friday and I was wondering if anyone can explain it
to me. Don't use lots of fancy scientific words because I don't
understand them. I don't think anyone can understand this except my 
teacher. If you could help me out I would appreciate it. Thank you.
                                          Joey

Answer:
Sorry, Joey, I have no idea why this question has gone unanswered
for so long.  It's really pretty easy: density of an object is
the object's mass divided by the object's volume.  You can measure
an object's density by weighing it and then measure its volume
by measuring how much water is displaced when you put the object
in a calibrated flask.  This all assumes the object is solid.
Any substance has a density, too, even liquids an and gases.  
Measuring their densities usually requires special equipment.
 
--- jade