Keeping You In Suspension

By: Sarah Conner

#My Idea

This project is testing which materials are best for building bridges.

Materials

straws, duct tape, Scissors, 2 large paperclips, 2 small paperclips, paper cup (at least 8 ounces), 300 pennies, metric ruler, notebook, pencils

#Problem

Will straws or pencils hold more pennies?

#Hypothesis

I think that the pencils will hold up more pennies because they are stronger.

Independent Variable

Straws, Pencils

Dependent Variable

Amount of Pennies

Controlled Variables

Cup brand, type of paperclips

Procedures

1- If your straws are the flexible type, cut the flexible type off.
2- Cut ten straws this way.
3- Make sure they are all the same length.
4- Cut 2 pieces of straw, each 3 cm long.
5- Tape 2 long straws on both sides on one of the short straws.
6- Do this at one end of the long straws.
7- Then tape the long straws together at the end.
#8- This is a tower for your suspension bridge.
#9- Redo step 5-8 to make a second tower.
#10- Tape one tower to a piece of furniture.
#11- Tape the second tower to a piece of furniture the same height.
12- Position the 2 towers far enough that you can place a straw in between.
#13- Place another straw between the 2 towers so its ends rest on the short straws.
14- This straw is the bridge deck.
15- Now you have a simple beam bridge.
#16- Make a load tester by unbending a large paper clip into a V shape.
#17- Poke the ends of a thick cup, just below the thick rim.
#18- Use a second large paperclip to hang the load tester over the bridge deck.
19- Do this by attaching the 2 large paperclips together, and then sliding the new one around the bridge deck straw.
#20- In your lab notebook, make a data table which has 3 trials and the number of pennies in each trial.
#21- Add pennies in the paper cup until the bridge fails.
#22- Record how many pennies it held on the first trial and then do it 2 more times.
#23- Now, to do the same things but with pencils, you take 5 unsharpened pencils and 2 thin glue sticks.
24- So take 1 glue sticks and tape 2 pencils on both sides of the glue stick.
25- Repeat that again to make a second tower.
26- Tape 1 tower on apiece of furniture, and tape the other tower on a piece of furniture that is the same height.
27- Take the last pencil and place it between the pencils so it can lay on the glue sticks.
28- Use the load tester from the previous part of this experiment, and hang it of the pencil in the middle.
29- Keep adding in pennies until it fails.
30- Record how many pennies that it held in your lab notebook.
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#Results

It turned out that the pencils held more pennies than the straws.

#Conclusion

My hypothesis was correct because the pencils did hold more pennies then the straws. The importance of this project.