Question

How do you find density by water displacement?

Answer 1

ok first things first what is density?
lets see equation for density:
rho = m / V
so we see it is mass that ocupies certain volume right?
mass is easy to get, just take a scale and weigh it and you got mass, volume is another sotrry
it is easy to calculate volume if you have regular shape at hand ie cube but what if you take a rock from forrest and want to know its density?
you weigh it and then put trough water displacement ie you take a graduated cylinder and pour in water to certain mark, lets say 50 ml and then you put in there that rock and volume will rize and lets say it rizes to 55 ml, that means that this rock we put in displaced volume of water equal to 5 ml ie volume of rock is 5 ml
and then just divide those two numbers and there is your density...
got it?

Answer 2

What two numbers are you dividing? 55/5 ?

Answer 3

no, acording to density equation you need to divide mass with volume so lets say that rock weighs 20 g and it displaced 5 ml of water so density would be
rho = m / V = 20g/5ml = 4 g/ml or 4 g/cm3
get it?

Answer 4

So, it's whatever the rock weighs divided by the displacement?

Answer 5

yes

Answer 6

OHHH okay haha thank you so so much! Is it okay if I ask you one more question?

Answer 7

i think rules state that you need to open another question but ask, ill try to help

Answer 8

haha. My question is that if i had 705kg/cu.m , what would that be in grams/cubic cm? And can you explain how to get it?

Answer 9

just so you can picture it more clearly take measuring tape at home and measure 1 m * 1 m cube on the flor and then measure 1 m in the air, now that cube if filled with water would weigh about 1 t or if you want 1000 kg!!! now take 1 tea spoon of water that is cca. 5 ml of water and that weighs 5 g because density of water is 1 g/cm3 or 1 kg per dm3 or 1000 kg per m3

Answer 10

sorry i made a misstake when i wrote that before...
1 g/cm3 = 1 kg/dm3
so if you need 705kg/m3 in g/cm3 you first need to ask yourself how much grams is in one kg and how much cm3 in m3

Answer 11

1 kg is equal to 1000 g and 1 m3 is equal to 10^6 cm3 that is 1000000 cm3

Answer 12

now to calculate 750 kg/m3 * 1000/10^6 = 750 *0,001 = 0,75 g/cm3