What affects the stretch of a string

Aim- For this investigation I am going to find out how the weight added to the spring affects the spring’s lengths and extension. This is what the extension is-

        10 mm

        

        1 N

        2N

        

Fair test- For this experiment to make it a fair test I will only change the weight added to the spring. The things that will be kept constant will be-

• The length of the spring
• The material of the spring
• The diameter of the spring

This will keep them constant by using the same spring.

Prediction- My prediction for this experiment is that if you double the weight added, the extension will double, if you treble the weight, the extension will treble and so on. These all mean the extension is directly proportional to the load. This will all work until the spring reaches it elastic limit when the spring has broken and does not return to its original length. I have put my prediction as this as I have got this from Hooke’s Law reference page eight on ‘Focus on Science’. I also predict that if enough weight is added, the spring will reach its elastic limit and break, or not return to its original length.

Apparatus- These are the apparatus that I will be using for this experiment-

• A spring
• A ruler (half meter)
• A stand
• Weights
• Clamp

Diagram        Clamp

        

 

Spring

        Stand

        Weight

        Ruler

        

Method

First I will set-up the apparatus as shown in the diagram. I will then add one weight  (1 Newton) to the spring and record the extension. I will then take the weight off and see if the spring has returned to its original length. I will then carry on this procedure up to 6 weights, (6 Newtons) recording the extension, and seeing if the spring is at its original length for each weight (Newton.) I will then plot the results of the experiment into a graph.

Safety

For this experiment I will be following all the laboratory rules, and using the weights carefully, by adding the weights sensibly.

Results

Table 1

 This was my first set of results, for what affects the stretch of a spring. I looked at these results and thought back to Hooke’s law, which tells me that if you double to weight added, the extension will also double. In these results I can see that it does not reflect back to Hooke’s law, so I must of done the experiment wrong. I decided to the experiment again. These are my new results.

I recorded the results for up to 10 Newton weights added. I then decided to see how many weights added until the spring reached its elastic limit, which was 13 Newton’s.

I knew the elastic limit had been reached because the spring did not return to its original length after 13 weights were added to the spring.