[dustymcawesome]

a circular mud puddle with an average diamater of 2.75 is covered with an even layer of oil on its surface. The oil causes the puddle to display the color's of the spectrum (rainbow) when subjected to bright light. The layer was created using 3 drops of oil, each with an average mass of 1.23 grams, and the density of oil is .774 g/cm3

A.) Calculate the thickness of the oil layer on the surface of the puddle.

B.) If we were to create a similar on another puddle with twice the diameter of the first puddle, how many drops of oil would it take?


I need all the help I can get....

Thanks in advance! :]

[dustymcawesome]

Well, for A.) I came up with h=0.803cm

And for B.) I got 19 drops....

[Borek]

Neither looks correct. Show how you got them.

[jarman007]

V=mass/density

V=4.77 cm3


(area of circular mud puddle) X (thickness) = volume

thickness=0.803cm



b) for this part follow same steps as in a) but in reverse order

first find volume then mass

from mass u can get no of drops

i got 12 drops


i hope i am right

[Borek]

12 drops in not 19, but it is OK.

What units is the puddle diameter in? You have calculated as if it was in cm, somehow I doubt - for the rainbow to be visible thickness of teh oil layer must be similar to that of visible wavelength. That's below μm range, not close to cm.

[JGK]

I get the same results but:


1.6 mL per drop! that is one jumbo economy size drop