Fishing wire investigation

Prediction

I predict that the wire will snap at around 600g because that is what the manufacturers say is the maximum weight is.

Apparatus

Equipment

• Retort stand
• Universal Clamp
• Fishing Wire
• Weights (100g)
• Clamp
• Mat For Floor

Safety

• Make sure there is space to work
• Keep clear of mat so the weight doesn’t hit your feet
• Clear the area

Method

1. Put the retort stand on the edge of the table
2. Clamp it down so it is unable to topple over
3. Attach the universal clamp to the retort stand(End is over the edge of the table)
4. Lay the mat down directly below the end of the universal clamp (To reduce damage to the floor)

5. Cut 20cm of fishing wire

6. Tie the fishing wire over the end of the universal clamp (Try to use a fishing knot, as it will give a more accurate result)

7. Connect a 100g weight to the end

8. Keep adding weights until the wire breaks

9. Repeat steps 5,6,7 and 8

Results

Graph

Analysis

We used a fishing wire that should withstand 600g, as you can see it didn’t. The first time we tested it, it broke at 200g which is 1/3 the tensile strength it should have been. The second time we tested we had to change the type of knot we used as we could not tie it ourselves. Also we found it hard keep the length of wire at 20cm because the knot was different sizes each time.

Conclusion

I believe that the test wasn’t very fair, because we changed the knot halfway through the test, we could not keep the length of wire the same each time because the knot would change size each time, also the knots took us a while to tie as they were very small, and therefore we only got four tests in. The tensile strength on the packet said it was 600g but we didn’t get that any of the times, this could be because it would be attached to a fishing rod, which would bend with the string whereas the universal clamp was clamped straight. I would improve it by having somebody in our group that could tie a fishing knot accurately, doing more tests, using a material more like a fishing rod and using smaller weights to add more accuracy.