You need to answer only 8 of the following. You MUST circle the question's number in order for the question to be graded. (Or else, the instructor will grade the first 8 questions and not look at the final ones.)

1. How did we more easily visualize whether cold seawater would be above or below warm seawater? (Hint: just trying to layer one atop the other is rather difficult to observe any interface between them. What was done to make it easier to see?)
   
   We added colored dyes to the various layers.
   
   
2. How did the densities compare between the small lead cannon ball and the lead beebee that Galileo dropped simultaneously from the Tower of Pisa?
   
   Both are lead, and that is all that matters: both have the same density.
   
3. Which was denser, Buzz Aldrin's rockhammer or the duck's wing feather? the rockhammer

   Had Galileo dropped that hammer and feather from the Tower of Pisa, what would have been the result?
   
   rockhammer plummets first followed by the slowly falling feather
   But when Astronaut Aldrin completed Galileo's experiment on the surface of the moon, his result was different. Why?
   
   There was no air to cause "drag" (air resistance).
   
   

4. Mary Lou has a chicken egg and wants to know its overall density. The egg weighs 38.291 grams. Into a graduated cylinder containing 39.2 ml of water, she slips the egg carefully. The egg completely sinks and she reads the cylinder now at 79.8 ml.
   1. Using ML's data, what is the density of the egg?
      
      38.291/(79.8-39.2) = 0.943 [note: 3 significant figures!]
      
      
   2. Do you give ML praise for good work, or tell her that she did something wrong? Why?
      
      Point out that the egg sank in the water and thus its density MUST be greater than 1.00.
      
5. A fiber from a piece of wood was isopycnographically determined to have a density of 1.682. What is the fiber's density?
   
   
   Oops! I meant to ask what is the fiber's specific gravity. So this question was truly a gift: answer = 1.682 gm/cc
   
6. On the wall nearby, you will see that C (carbon) and Pb (lead; plumbium, as in plumber, a person who works with lead pipes and joints) are in the same column of the periodic table (meaning they share a number of chemical properties). B and Tl are similarly in one column. Which would you expect to be denser, and why?
   
   
   Going from the familiar to the unfamiliar: you know that Pb is denser than C, thus you should conclude that Tl is denser than B.
   
7. Order the following from least dense to the most dense (they are given in alphabetical order here):

   Aluminum (Al), Hydrogen (H), Lead (Pb), Platinum (Pt), Silver (Ag), Uranium (U).
   
   
   You got full credit for:
   H, Al, Ag....
   It turns out that at the heavier atomic numbers, the trend no longer continues.
   Answers to the following should reflect the appropriate number of significant figures.
   
   
   

8. Silver has a density of 10.5 g/cm ³. 
   Calculate the volume in cm ³of 3.265 g.
   
   
   1 cc/10.5 g = V / 3.265 g
   V = 3.265/10.5 = 0.310 cc
   10.5 is three significant figures; 0.310 is also three significant figures.
   
   
   
   
   
9. The temperature of the surface of the sun is 5.5 x 10 ³°C.
   Calculate this temperature in °F and in °K.
   
   
   Note that 5.5 is two significant figures!
   
   5.5 x 10 ³°C = 9.9 x 10 ³°F
   
   
   5.5 x 10 ³°C = 5.8 x 10 ³°K
   
10. Some soft drinks are sold in bottles with a volume of 1.5 L.
    Calculate this volume in mL, in cm ³ and in dm ³.
    
    
    Again note 1.5 is two significant figures!
    
    1.5 L = 1.5 x 10 ³ ml
    1.5 L = 1.5 dm ³ ml
    
11. (Betcha can't do this one!) What is the density of water in pounds/cubic foot?
    
    
    1.00 inch = 2.54 cm; 1 foot = 30.48 cm
    I cubic foot = 30.48 ³ ml
    = 28,317 ml = 28,317 gm = 28.317 kg
    1 kg = 2.200 pounds
    28.317 kg = 62.3 lbs