The Factors Affecting the Deflection of a Spaghetti Bridge

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The Factors Affecting the Deflection of a Spaghetti Bridge

An Investigation into the Factors Affecting the Deflection of a

Spaghetti Bridge - Planning

* Preliminary Work

I have decided to investigate how different masses affect the

deflection of a spaghetti bridge. We have been given a selection of

different types of spaghetti. To find the type that will give me the

largest range of results I need to test each type to find the one with

the largest breaking force.

To do this I held the spaghetti in two clamp stands (one at each end

of the strand) and then applied a mass to the centre of the spaghetti.

Starting at 10g and increasing the mass by 10g each time. Each type of

spaghetti was cut to the same length of 20cm. I found that the

"Waitrose Italian Spaghetti" had the largest breaking force of

approximately 90g.

I predict that the deflection of the spaghetti bridge will increase

proportionally to the mass applied. I believe this because spaghetti

is an elastic material (it will return to its original shape when a

force is applied) and Hooke's law states that for elastic substances

the extension (deflection) is directly proportional to the stretching

force (mass applied). However, all materials have an elastic limit

(when too much mass is applied then it will no longer return to its

original shape) and will break. If the elastic limit is exceeded then

the deflection in no longer proportional to the mass applied.

* Investigation

* Hold a piece of Waitrose Italian Spaghetti in two clamp stands.

Position them so the distance between the place where the spaghetti is

attached is 20cm.

* Find the mid point ...

... middle of paper ...

... future I would attach

the mass to the spaghetti using cotton thread tied tightly so it would

not move.

To improve the experiment I would find a more accurate way of

measuring the deflection. Since using a millimetre marked ruler was

cumbersome and the spaghetti was more than 1mm thick therefore it was

difficult to decide where to measure the deflection from. I would also

find a way of preventing the ruler and hanging mass from interfering

with each other since they got in each others way during the

investigation.

Additional work, which could be carried out, is to repeat the

experiment using, a wider range of lengths of spaghetti. The

investigation could also be extended to investigate other factors

affecting the deflection such as number of strands of spaghetti,

thickness of spaghetti or type of spaghetti.

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