1028 words - 5 pages

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:

=====================

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

...view middle of the document...

The equation for moment was cited from Tom Duncan's GCSE Physics book

3rd edition.

Obtaining Evidence

Procedure:

I did the experiment exactly how I planned out earlier, with the

exception of adding some double-sided adhesive tape to the rod so the

weight would not slip down the rod whilst reading the amount of

deflection.

Safety measures:

I made sure that all unused weights were placed away from the table

edge so they would not fall onto my foot. I also made sure that no

more than 500g was put onto the rod in case it were to snap and a

splinter were to come into my eye.

Results:

Weight (N)

1st Reading

(mm)

2nd Reading

(mm)

3rd Reading

(mm)

Average Reading

(mm)

0

1

2

1

1

0.5

12

11

12

12

1

42

43

43

43

1.5

65

67

66

66

2

86

84

86

85

2.5

110

112

114

112

3

133

131

133

132

3.5

146

150

150

149

4

170

175

177

174

4.5

190

185

191

189

5

212

215

216

214

Analysis and Conclusion

Conclusion (eg relationship between variables as given by graph)

I have to come the conclusion that the more weight added to the dowel,

the more it will deflect. Looking at the graph, it appears that the

relationship between the two variables is linearly proportional,

seeing as the line of best fit does not pass through the origin.

Scientific explanation of results (including comparison with

prediction, where appropriate):

In the planning stage, I predicted that the relationship between the

two variables would be directly proportional, but given that the

conclusion that the relationship is linearly proportional, it shows

that my prediction was wrong.

If you consider the dowel to be like a spring, it is easier to see why

the results are proportional. If the top half of the length of the

dowel is under tension when being bent, and the bottom half is under

compression, like Hooke's Law, a spring will extend or shorten if

pressure is...

Tap into the world’s largest open writing community