Science exam answers Lesson 6

Buoyancy Basics

a) What are the two forces that act on a ship in the

ocean?

b) State Archimedes Principle in your own words.

c) How does the size of a boat’s hull impact its ability

to float?

a) Gravity (downward force) and buoyancy (upward

force)

b) Buoyant Force = Weight of the displaced fluid. In

other words, if the object weighs less than the

amount of water displaced, the object will float.

c) The wider and longer the hull (bottom of boat), the greater

the ability to float (buoyancy).

Oil and Water

a. What is an oil boom?

b) What are the four types of booms?

c) How does the difference in density between oil and

water play a role?

a) A floating barrier placed over a stretch of water to

prevent the passage of oil, especially following an

oil spill.

b) Foam-Filled Booms, Inflatable and Self-Inflating

Booms(air), Fire Booms(heat resistant), and Trash

and Debris Booms(PVP and metal)

c) The density of oil is less than the

density of water. Therefore, the oil floats to the top

of the water.

Airships, Balloon and Blimps

a) Why do helium balloons float?

b) What is the force acting on the balloon?

c) Why does the hanging balloon appear to move

backward?

d) Why does the pressure change in the box when it is

moved?

e) Why does the floating balloon appear to move

forward?

How does this relate to a balloon rising into the sky?

a) Helium is less dense than the air around the

balloon.

b) The buoyancy force

c) The balloon wants to stay in place. Only the box

moves.

d) The air particles are moved to the back of the box

creating greater pressure at the back of the box.

e) The pressure at the back of the box pushes the

helium balloon forward.

How does this relate to a balloon rising into the sky?

The balloon moves from a higher pressure near the surface

of the earth to the lower pressures further from the earth.

Submarines

a. What are the tanks on the side of a submarine

called?

b) Describe the tanks when the submarine is floating

on the surface (positively buoyant).

c) Describe the tanks when the submarine is sinking

(negatively buoyant).

d) Describe the tanks when the submarine is

submerged (neutrally buoyant).

a) Ballast tanks.

b) The external ballast tanks are full of air.

c) Water is allowed into the external ballast tanks and

water pressure ejects the air in the external ballast

tanks.

d) The external tanks

are empty but the internal ballast tanks are filled

with air.

Swim Bladders

a. What is a swim bladder?

b. How does a fish float closer to the surface?

c) How does a fish float closer to the bottom?

d) How can eating affect a fish’s ability to swim down?

e) What is swim bladder disorder?

a. A swim bladder is an organ in fish that can expand

and contract.

b. A fish increases gas to the swim bladder.

c. A fish decreases gas from the swim bladder.

d. Fish can swallow air when eating from the surface

of the water.

e. Swim bladder disorder is when fish are not able to

swim down. When ingesting air, the fish will turn

upside down. The air in its intestines cause this

issue. The other form is when there is a problem

with the swim bladder itself. This usually leads to

the death of the fish.