3. Monday, March 3 rd : “A” Day Tuesday, March 4 th : “B” Day Agenda  Check lab write-ups  Pre-lab safety items/discussion  Lab: “Polymers and Toy Balls”  Completed lab will be due next class period

4. Lab: “Polymers and Toy Balls” Safety Guidelines  The latex is in the hood because the vapors are unpleasant! (stinky!)  The ethanol is in the hood because it is flammable!  Keep all of these bottles tightly closed when they are not in use.  Wear gloves when told to do so in the procedure.

5. Lab: “Polymers and Toy Balls” Lab Discussion  Be patient when rolling the ethanol-silicate polymer into a ball. If it crumbles, a few drops of water will rehydrate it so it can be reshaped into a ball.  Try to get the balls as round as possible. This will make it easier to determine their volume and how high they bounce.

6. Lab: “Polymers and Toy Balls” Lab Discussion  Remember, this is chemistry class. Use centimeters (cm) when recording the height the balls bounce and use grams (g) to record the mass. You will probably need more than 3 trials to get an accurate bounce height.  Record the bounce height (cm) in Table 1.  Record the mass (g) and diameter (cm) in Table 2. Make sure your data has the correct units!

7. Lab: “Polymers and Toy Balls” Lab Discussion  In the Analysis section: 1)The chemical formulas are:  Latex monomer: C 5 H 8  Ethanol-silicate polymer: SiC 4 H 10 O 3 Remember: ALL lab questions need to be answered using complete sentences!

8. Lab: “Polymers and Toy Balls” Lab Discussion 5) Do not use water displacement to measure the volume, the ethanol-silicate polymer will dissolve. Use the formula for the volume of a sphere: Volume = 4/3 ∏ r 3 6) Remember, density = mass volume Be sure to SHOW ALL WORK and include proper units!

9. Lab: “Polymers and Toy Balls” Lab Discussion  You may take the latex bouncy ball home at the end of the day.  There are baggies and labels on the back table.  Put your labeled bag on the cart and pick it up after homeroom…

10. Lab: “Polymers and Toy Balls”  Conduct “Polymers and Toy Balls” lab safely! Have