1. Drill Quiz (No Talking) 5 min
Significant figures reflect an experimenter’s….his/her measurement.
What is the process called when a liquid is boiled to produce a vapor that is then condensed again to a liquid?

2. Objective:
SWBAT: Determine the density of an object in order to calculate percent error.

3. SAT Enrichment Exercise:
A student collected the following data in the lab
What is the density of the mineral?
a g/cm3
b cm3/g
c g/cm3
d cm3/g
e g/cm3
Data Table
Mass of mineral
46.84 Grams
Volume of water
19.50 mL
Volume of water and mineral
41.80 mL

4. Density
What are the units?

5. Coke Vs. Diet Coke Density Demo Which one will float?
Which one will sink?

6. Riddle
An old riddle asks, “Which is heavier, a pound of feathers or a pound of lead?” The answer is obvious, of course, since a pound of feathers and a pound of lead both weigh the same, one pound. However, there is clearly something different about a small piece of lead and a large bag of feathers, even though they weigh the same. What is this difference?

7. Density Determination
Pre-Lab
Are there any questions about the pre-lab???
What are the units used for density? How are they interchangeable?
density units g/mL and g/cm3 (1mL = 1cm3).

8. Density Determination
What is the formula for percent error?
% Error = Measured Value – Accepted Value x 100
Accepted Value
What is the difference between measured value and accepted value.
Measured is your value and accepted is the true or actual value

9. Don’t forget your lab aprons and safety goggles.
Let’s get to work!
You have 40 min to complete the lab.
Don’t forget your lab aprons and safety goggles.

10. Time is up!!!
Come back to your seats and seat with your lab partner to complete your analysis questions.

11. Analysis Questions
Complete Analysis Questions. You will have 23 min.

12. Analysis Question #3 Right I. Solid = .639g/cm3 Left
II. Liquid = .997 g/mL
III. Metal = 3.04 g/mL
IV. Metal = 2.26 g/cm3
Left
Solid = .449 g/cm3
Liquid = .996 g/mL
Metal = 3.06 g/mL
Metal = 2.25 g/cm3

13. Summary How successful was your lab investigation?
What criteria did you use to assess your error?

14. Summary
Why was it important to have accurate measurements for this lab?
Was the objective accomplished? Explain how we completed the objective.

15. Summary What were some sources of error for each section?
Rectangular Solid
Liquid Displacement
Metal cylinder by water displacement
Metal cylinder by formula method

16. Extension Complete the Exit-Ticket: Homework:
Place in the bin when finished.
Homework:
Complete Analysis questions to lab if you did not finish during class.
Complete Benchmark Review packet
Study for Test next class period.
All Make-up Work is due Next Class!

17. Problem #1
The students were given the task of finding the density of a brownie. Johnny decided to eat ½ of his brownie. How would Johnny’s results compare with the rest of the class? Explain.

18. Problem 1 Answer
Johnny’s answer would be the same as his classmates because density does not depend upon the amount or size of a substance but on the composition of the substance.

19. Problem #2
Describe in detail how you would determine the density of a potato that is too large to fit into a graduated cylinder.

20. Problem 2 Answer
a. Use the balance to mass the potato. Fill a container that can hold the potato with water. Slowly place the potato in the container catching all of the run-off in a second container. Find the volume of the run-off using a graduated cylinder. Calculate the density.
b. Cut the potato so that it will easily fit into a graduated cylinder. Use the balance to mass the piece of potato. Place some water into the graduated cylinder. Record this as the starting volume. Slowly slide the piece of potato into the cylinder. Record the new water level. Calculate the volume by finding the difference between the two water levels. Calculate the density.