An old fashioned way of measuring depth is to have a tube open at one end coated
ID: 249286 • Letter: A
Question
An old fashioned way of measuring depth is to have a tube open at one end coated inside with a soluble (meaning it dissolves) substance such as sugar. A diver (here on Earth) takes the tube, closed end up, underwater. On the surface of the water the tube is completely filled with air. As the diver dives the water rises up the tube washing away the sugar. In this question assume that the density of seawater is given by ? = 1027 kgm-3 and the temperature is a constant 15.0 oC. The cross sectional area of the tube is 1.584 cm2.
What is the pressure 10.1 m under water?
Answer Pa
The tube is 34.9 cm long. What length of sugar remains in the tube when the diver surfaces from this depth?
Answer cm
Hint: Revise the ideal gas law from the hot air balloon topic. The sugar will remain where it is in contact with the air so you will need to consider what volume of air is there within the tube?
NNNNN water closed end sugarExplanation / Answer
the pressure inside the tube when thetube at 10.1 is
1027*9.8*10.1 + 1.013x10^5 = 2.030x10^5 Pa
at constant T, we have
P1V1= P2V2
1.013x10^5 *34.9*A = 2.030 x10^5*L*A
L= 1.013/2.030*34.9 = 17.4 cm