density

Question 1

what is density

Answer 1

mass per unit volume

Question 2

formula for density

Answer 2

p=m/v
density (kg/m^3) = mass (kg)/volume (m^3)

Question 3

Describe how to find the density of a solid, regularly shaped object

Answer 3

gather equipment
[] mass balance
[] ruler
[] object (metal cube)

-place the object on the mass balance and record its mass

[] if displayed in grams, convert to kilograms

-measure the object’s side lengths with a ruler and convert to metres before multiplying together to find the object’s volume.

-divide the mass by the volume to find the object’s density in kg/m^3

Question 4

Describe how to find the density of a solid, irregularly shaped object

Answer 4

2 methods

• method 1
  [] gather equipment (eureka can, water, measuring cylinder, object, mass balance)

[] measure and record the object’s mass using the mass balance and convert to kilograms if necessary

[] fill the eureka can with water until just under the spout’s opening, and place the measuring cylinder underneath the spout of the eureka can (if needed, put the can on a flat surface to raise it so that its spout is just above the measuring cylinder’s opening)

[] gently place the object in the eureka can, being careful not to splash any water out of the can

[] wait for water to stop flowing into the measuring cylinder

[] read and record the volume of water displaced and collected (this is equal to the object’s volume)

[] use the equation mass/volume = density to calculate the object’s density

method 2
[] same thing but without the eureka can - just record the original volume of water in the measuring cylinder (fill about halfway)

• then record the end reading when object is placed in and take away the final reading from the initial to get the object’s volume
  NOTE: when reading from a measuring cylinder, use the MENISCUS at eye level

Question 5

Describe how to find the density of a liquid

Answer 5

-using a mass balance, measure and record the mass of the empty measuring cylinder

-measure certain volume of liquid using the same measuring cylinder

[] record the volume measured out and convert to m^3 if needed

-measure the mass of the liquid and the measuring cylinder together using the mass balance again

-take away the empty cylinder’s mass from the total mass, then convert mass to kilograms if needed

-use density = mass(kg)/volume(m^3) to find the liquid’s density

Question 6

how to find mass

Answer 6

m=p x v

Question 7

how to find volume

Answer 7

v=m/p