1. Measurements September 20 th -23 rd

2. Types of Measurements Mass- triple beam balance Length- ruler/meter stick Volume- volumetric flask/ ruler Temperature- thermometerc Time- stopwatch Density- triple beam balance and ruler/flask

3. Types of Units All measurements are measured using metric system… Units fall into two categories: – Base- units produced by solely one measurement Mass Temperature time – Derived- units produced by the combination of more than measurement Volume- (length X width X height) Density – (mass/volume)

4. A few reminders for taking measurements… Always estimate one digit The number of digits written will be the number of sig figs the measurement has Always include the appropriate units based on the measurement taken. Convert the units if needed…

5. Basic Conversions Once measurements have been taken sometimes they must be converted from one to another. Ladder of Conversions allows us to go from one unit to another.

6. Conversion ladder

7. Practice using the ladder Using the ladder complete the following conversions: 506 mm = ___ dm 7.4 kg = ____ mg.34 L = ____ cL

8. Dimensional Analysis A step by step process that allows you to complete basic conversions Requires use of a conversion factor: – A conversion factor is a fraction that allows you to either multiply by a factor of 10 or divide by a factor a 10. – Conversion factor allows all units to cancel so you are left with the units you are trying to reach.

9. Using Dimensional Analysis Example: 4.5 L = ____ mL Steps: 1)Write out the number you start with including units. 2)Leave space, put an equal sign and write the units you are going to. 3)Insert conversion factors 4. 5 L X = ____mL Conversion factors for L and mL 100ml or ___1L__ 1 L 1000mL

10. A few practice: 1)25 g = ___kg 2) 32 cm = ___mm 3) 2.3 g/mL = ___ g/L

11. Regular Solid Cube: Length 3 Rectangular Prism: Length x width x height Cylinder: π r 2 h

12. Irregular Solid Mass/volume Volume = volume displacement Pour water into a graduated cylinder or beaker, add substance and measure how much the water changes.

13. Determining Density of a liquid

14. Density Practice: What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm 3 ? A cup of gold colored metal beads was measured to have a mass 425 grams. By water displacement, the volume of the beads was calculated to be 48.0 cm 3. Given the following densities, identify the metal. Gold: 19.3 g/mL Copper: 8.86 g/mL Bronze: 9.87 g/mL

15. Honors density problem: A little aluminum boat (mass of 14.50 g) has a volume of 450.00 cm 3. The boat is place in a small pool of water and carefully filled with pennies. If each penny has a mass of 2.50 g, how many pennies can be added to the boat before it sinks?

16. Homework Chapter Review- Tests – Monday September 28th- A – Tuesday September 29 th - B Density Pre-lab: Lab conducted September 28 th and 29 th