1. What is density? The mass per unit volume of a substance

2. Some things to know When we say that one object is heavier than another – I.e. A rock is heavier than a floating cork Actually it is denser Units: kg/m 3 or g/cm 3 Formula: D = m/V

3. Real-World Applications Cleaning up oil spills Making hot-air balloons rise Selecting motor oil for cars Making beverages

4. How to determine density A block of fir wood measures 10cm by 8cm by 3cm. It has a mass of 144g. Calculate the density of the wood. 1 st determine the volume of the wood. A regular shaped object can be determined using V=l*w*h. 10cm*8cm*3cm = 240cm 3 2 nd us the density formula D=m/V. 144g/240cm 3. D=0.6g/cm 3

5. Determining the volume or mass An unknown liquid has a mass of 150g. Its density is known to be 0.95g/cm 3. – V=m/D, 150g/0.95g/cm 3, V=142.5cm 3 An unknown liquid has a volume of 1250 cm 3. Its density is known to be 1.25g/cm 3. – M=DV, 1.25g/cm 3 * 1250cm 3, m=1562.5g

6. Practice Answers Problem 1 – D = m/V – 33750/(60*30*5) – D = 3.75g/cm 3 Problem 2 – V=m/D – 3883/1.03 – V=3769.9cm 3 Problem 3 – m=DV – 4000*1.23 – M=5040g