1. Density, Time and Temperature

2. Density Density is the ratio of the mass of an object to its volume

3. This equation can be written in different ways to solve for density, mass or volume.
D = m/V
m = D x V
V = m/D

4. Common units that we use when measuring density:
g/cm3 kg/m3 g/mL kg/L

5. If something has a large mass compared to its volume, it has a high density. This is like a set of weights which can be small but heavy.

6. But if an object has a small mass compared to its volume it has a lower density. This is like a piece of wood which can seem light for its size.

7. Different types of plastic, metal, wood, and other materials have different densities. The density of a material is based on the atoms or molecules the substance is made from.

8. Copper is more dense With small massive atoms that are packed closely together
Plastic is less dense Connected together in long chains and not packed as tightly as the atoms in copper

9. Density in sinking and floating
An object or liquid will float if it is less dense than the liquid it is in.
Density of water = 1 g/cm3

10. If 96.5 g of gold has a volume of 5 cm3, what is the density of gold?
D = m/V
D = 96.5 g / 5 cm3
D = 19.3 g/cm3

11. If the density of a diamond is 3
If the density of a diamond is 3.5 g/cm3, what would be the mass of a diamond whose volume is 0.5 cm3 ?
M = d x V
M = 3.5 g/cm3 x 0.5 cm3
M = 1.8 g

12. If a 96. 5 g piece of aluminum has a density of 2
If a 96.5 g piece of aluminum has a density of 2.7 g/cm3, what is its volume ?
V = m ÷ d
V = 96.5 g ÷ 2.7 g/cm3
V = 35.7 cm3

13. Units used to measure time:
Measuring Time
The SI base unit for time is seconds (s)
Units used to measure time:
Seconds (s), minutes (min), hours (hr), days, weeks, months, years
Tools or instruments used to measure time:
Clock, watch, stopwatch, hour glass, iphone

14. How many hours are there in 3 months?
3 week x 7 day/week x
24 hr/day = 504 hr

15. Measuring Temperature
Metric units for measuring temperature: Celsius (°C) and Kelvin (K) Instrument used to measure temperature: Thermometer

16. K = °C
°C = K – 273.5
°C = 5/9 (°F – 32)
°F = (1.8 x °C) + 32