Ice Breaker Hull Design science experiment | Fizzics Education

# Ice Breaker Hull Design

You will need:

Different toy boats, each with a different hull shape

Jelly crystals, enough for 2 litres

Newton spring balance from school

Large flat platter and a measuring scale

Small screw hooks and weights (metal nuts will do)

1

Make two litters of the jelly a few hours before hand and let it set.

2

Scape out some of the jelly and use it to cover the platter.

3

Weigh each boat and record your measurements.

4

Place a boat at the end of the platter and gently pull it through the jelly using the spring scale. Take not of the force needed to move the boat.

5

Repeat step 4 four each boat. Do you notice anything different? Is so why is this the case?

6

To make it a fairer test, weigh the lighter boats down with the metal nuts and repeat the experiment. Remember to make sure that the weight is evenly distributed along the boat.

7

Work out how you can make this an even fairer test.

For example: pulling from the same point of the boat, at the same angle, as the same speed, thought the same amount of jelly. Or should you use blocks with different shaped wedges attached instead?

### Why Does This Happen?

An object is set into motion when it is pushed or pulled, i.e. subjected to a force.
Force is measured in Newtons, which expresses the amount of energy being applied over a given distance and time. To pull the boat through the jelly required a certain amount of force to keep it moving. The greater the force applied, the greater the spring stretched within the spring scale.

Each boat would have had a different angle on it’s bow to cut through the jelly. If the boat had an acute angled bow (i.e. ‘sharp’), the boat would have neatly cut through the jelly and would have required less force to keep it moving. If the the boat was shaped like a barge, with a blunt front end, a larger force would need to have been applied to keep the boat moving at the same speed.

Ice breakers in polar regions are designed to slowly rise up onto ice, thereby allowing the weight of the boat and the shape of the bow (an inclined plane) to break the ice. This process isn’t performed at great speed as the ship can still be damaged. Dense pack ice cannot be negotiated as the ice floes are too thick, however thin ice of a few metres thick can be broken. Commercial shipping lanes within the Arctic circle are regularly cleared by ice breakers.