Friday, Sept. 6 th : “A” Day Monday, Sept. 9 th : “B” Day Agenda Density Activity Homework Questions/Collect (Pg. 19: 1-11) Section 1.2 Quiz: “Describing Matter” Lab Write-Up/Discussion: “Counterfeit Pennies” Reading/Writing Assignment We will be in the lab next class period – be sure to dress appropriately!
What is happening here? Observe the two cans of pop in the tank. You can come up for a closer look if you want… Take a few minutes to write a paragraph that scientifically explains what you think is happening.
Section 1.2 Quiz “Describing Matter” You may work with your 3:00 partner on the quiz. You will need a calculator. You MAY use your guided notes and your book. When you’re finished, turn it in and pick up your lab folder…
Counterfeit Penny Lab Mr. Vance received this memo at the High School and forwarded it to the Chemistry Department…..
S E C R E T S E R V I C E Secret Service Directive #1456Date: August 1, 2013 To: Department of Chemistry Morrison High School Subject: Counterfeit coinage Over the years, we have eliminated most counterfeiting operations in the United States. The Secret Service has confiscated illegal equipment, and the paper currency was changed to make counterfeiting more difficult However, counterfeiting of coins has increased because coins are easy to reproduce but hard to trace. Counterfeit pennies made in the 1970’s and 1980’s were produced by substituting less expensive materials. Such substitutions can be detected by measuring densities. Samples are enclosed for you to analyze. Your task is to identify the year that the counterfeit coins entered the marketplace. Include a hypothesis of which metal was used in the coins. We look forward to your quick investigation and response.
Lab: “Counterfeit Pennies” Update the table of contents in your lab folder with this lab. “Counterfeit Pennies” should be lab #2 in your lab folder. (#1 was “Lab Techniques” )
Lab: “Counterfeit Pennies” This lab is not a “cookie cutter” lab and doesn’t list the purpose, materials, or even the procedure. With your 3:00 partner, think of an experiment you could run to see if the pennies that you have are pure copper, or not… Hint: What did I do to see if the necklace that I “found” was pure silver?
Lab: “Counterfeit Pennies” Things to think about…. How many pennies should you use? Why? Are there any pennies you shouldn’t use? Why?
Lab Write-Up: “Counterfeit Pennies” When you’ve come up with a plan, check it with me, and then begin your lab write-up: Title: Purpose: Hypothesis: Materials: Procedure: Reflection Statement:
Lab Write-Up: “Counterfeit Pennies” After your reflection statement, include a data table that looks like this: Data Table #1 YearTotal Mass of Pennies Used (g) Volume of Water to Start (mL) Total Volume of Water + Pennies (mL) Change in Volume of Water (mL) Density (g/mL)
Density Calculations You will use water displacement to find the density for each year you test. Remember, the density formula: Mass of pennies used (g) CHANGE in volume (mL)
Lab Write-Up: “Counterfeit Pennies” After conducting the lab, the whole class will compile their data to create another table: Data Table #2 YearDensity (g/mL) Note: you will need a lot more lines than shown here…
Lab Write-Up: “Counterfeit Pennies” As part of your analysis, you will construct a graph with year on the x-axis and density on the y-axis using the data table created by the whole class. Title of Graph Density (g/mL) Year From this graph, you should be able to determine the year that the pennies changed composition.
Lab Write-Up: “Counterfeit Pennies” Conclusion Questions (Complete Sentences!) 1.What measurements are necessary to determine density? 2.Based you your graph, in what year did the counterfeit coins appear? 3.Using Table A-5 in the back of your textbook (pg 829-830), hypothesize which metal was used in the counterfeit coins. 4.How would mass measurements be affected if the pennies were still wet from volume measurements? 5.What do you think is the biggest source of error in this experiment? How could you minimize these errors in future trials?
Reading/Writing Assignment “5 Tanning Myths” I recently found this article in the paper and thought it was interesting and worthwhile to share. Read the article “5 Tanning Myths” and write a reflection, using the rubric as a guide. Respond critically to the article and be sure to follow the rubric for full points.
Looking Ahead Remember, we will be in the lab next time. Be sure to dress appropriately!
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