The Effect of Weight on the Amount a Fixed Dowel Deflects

The Effect of Weight on the Amount a Fixed Dowel Deflects

The Experiment:

How weight affects the amount a fixed dowel deflects.

Labelled diagram of proposed set up:

When reading off the ruler, it is necessary to crouch otherwise
parallax will occur and readings will be inaccurate.

Controlled variables:
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There are 4 independent variables in this experiment. The thickness of
the dowel, the weight being hung from the dowel, the distance the
weight is being hung from the dowel and the amount of over-hang of the
dowel. These will produce a dependent variable, the bend/deflection of
the dowel. I will use the weight being hung as my independent
variable, and I will keep the others constant.

Expected independent variable range:

I will take readings between 0-5N (0-500g) inclusive. From zero, I
will take down readings in 0.5N (50g) increments. Each reading will be
taken down 3 times with a margin of error of 2mm either way and to 0
decimal places. Once all 3 readings have been noted, an average
reading will be calculated.

Prediction, including scientific explanation:

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I believe that the deflection will be directly proportional to the
weight being added onto it.

This investigation appears to test the understanding of moments. The
equation for moments is: moment = force x perpendicular distance to
fulcrum.

If the distance will be kept constant, then I can rewrite the equation
into:

Moment = force x X, where moment =1, force = 1 and X is constant.

If the force were to be doubled, then force = 2, thus on the right
side of the equation, force multiplied by distance gives 2X, so moment
must equal 2X too.

Sources of information, including results of preliminary trials:

I conducted some preliminary trials, where I used a 1cm thick dowel. I
found that the deflection was too small to measure accurately, so a
decision to use a thinner dowel was made.

The equation for moment was cited...