By Sim WenHong 1P3 (23)

What is density?What is density? Density isDensity is

1. 1. a matter that has physical propertiesa matter that has physical properties

2. how packed a material is2. how packed a material is

Density = mass or weight/

IMPORTANT!!!

Basic calculation of density

Density =

         

mass__ volume 

Example question

If a aluminium is 1.35 kg and its volume is 500ml, calculate the density of the aluminium block in g/ml.

Density = mass__ volume

1.35kg = 1350g

Therefore,

Density of aluminium block is

1350g = 2.70g/ml !!! 500ml

Things to remember:

1.Write the formula

2.Convert the units ( if needed)

3. Give your answer in mass units/volume units

Oh I heard you! You were saying

Now, for the more difficult ones….

Example question ( higher level)Example question ( higher level)

A student has measured the mass of a rock as 42.00 g. To determine the volume, the student places the rock into 21.0 ml of water. The rock causes the level of water to rise by 6 ml. What is the density of the rock sample ?

Its 7 g/ml !!!!

Volume of rock = the amount of water risen

= 6ml Density = mass__ volume

Density of the rock = 42.00g 6ml

= 7g/ml !!!

To calculate volume for cylinder

π r2 h

Now for the really difficult questions…

A cylindrical vat filled with root beer with a total mass of 42578 kg. The vat has a diameter of 28.3 cm and is 6 m tall. State the density in kg/m3 of the combined vat and root beer.

Still remember how to calculate a cylinder’s volume?

The answer is 112938.99 kg/m3 !!!!!

Radius of cylinder is 28.3/2

= 14.15cm

= 0.1415m (estimated)

Height of the cylinder = 6m

Volume of cylinder = π r2 h

= π × 0.1415 × 0.1415 × 6

=0.377 m3(estimated)

Density = mass__ volume =42578kg 0.377m3 =112938.99 kg/m3 (estimated)

 

Lets share some interesting facts with you…

Everyone knows that ice floats on water, but do you know why and how it is abnormal?

Things float when it has less dense than its surrounding liquid or air.

An example would be that oil floats on water .

The density of oil is 0.92 g/cm3 while

The density of pure water is 1.00 g/cm3.

And since oil floats on water, we can prove that an item with less dense floats!

Why things float?

The abnormalities of ice

Did you know that it is abnormal for ice to float on water?

It is abnormal as it is usually the case that a solid of its compound would sink in its own liquid.

Credits

http://www.riverinstitute.ca

http://www.ajdesigner.com/

http://www.elmhurst.edu

And to search engine

www.google.com

And pictures from clip art