1. Internal 3 Credits DO NOW: Turn to page 175 and do the puzzle on the bottom right – Three faces of a cuboid.

2.  What is it?  The density of an object is its mass (how heavy it is) for a standard (or given) volume.  Units for density?  kg/m 3 or gm/cm 3

3.  Three identical buckets. Cork, Water and Gold.  Do the buckets have the same volume?  Arrange from lightest to heaviest.  Which has highest density?

4.  Mass = Volume x Density  M = V x D  V = M / D  D = M / V M VD

5. Gamma Mathematics Workbook © Pearson Education New Zealand 2007 = 2.3 x Calculate the weight of a block of concrete that measures 15 cm by 12 cm by 10 cm. The density of concrete is about 2.3 g/cm3. 10 cm 15 cm 12 cm Volume = = 1800 cm3 12 x 10 Weight = = 4140 g = 4.14 kg 15 x Density x Volume 1800

6. Gamma Mathematics Workbook © Pearson Education New Zealand 2007 A 10 kg block of gold has a volume of 518 cm3. Calculate the density of gold in g/cm3. = 19.3 g/cm3 Substitute, remembering to turn kg into g.

7.  Do the following practice exercises on page 176 and 177.  2, 3, 5, and 6.

8.  Uses 4 digits to give any time between midnight and midnight of the following day.  Goes from 0000 (midnight on day 1) to 2400 (midnight the following day).  First 2 numbers are the hours after midnight and the second 2 numbers are the minutes.  2400 hours is also 0000 hours, as it is the start of the next day. Convention is that 0000 is used to define the start and 2400 the end of the day.

9.  0800 (read as oh-800) is 8:00 am  2315 (read 23-15) is 11:15 pm  Try the following exercises on page 178:  1, 2, 5, 6, 7, 13 d - i