Lab Experiment 4: Observing the Malleability of Paperclips

September 23, 2008 Observing the Malleability of Paperclips Julie Anne A.


Day 1, Period 4


Purpose: To observe how many bends it takes for a paperclip to break without any treatment;
after being heated then cooled slowly; and after being heated and rapidly cooled by
plunging it to a beaker with cold water.


Materials:

• a big paper clip



• bunsen burner



• 100 mL cold water in a beaker

Procedure:

1. Straighten the paper clip by undoing its curves.



2. Bend the straightened paper clip backwards and forwards. Then, count how many bends it took for the paper clip to break in half.



3. Heat the half of the paper clip in a bunsen burner with a roaring flame for 10 seconds or until it glows. Then, put that paper clip in the beaker with cold water and wait for it to cool.



4. Take the other half and heat it again for 10 seconds with the roaring flame in the bunsen burner. Then , put it on the safety mat and wait till it cools.



5. When both of the paper clips cooled, take one and give the other one to your lab partner and do the procedures 1 and 2 again.



6. Record your observations.

Data and Observations:

1.) Paper clip without any treatment

Number of Bends: 6 bends

Before: The half paper clip was hard and pointy. It could poke and wound you. It didn't have odour. it felt a bit smooth but there were a lot of little bends on it.

After: When I bend and bend and bend the straightened paperclip, the spot where i bet it sort of lose its color. After losing its color, it breaks.

2) Paper clip plunged in water

Number of Bends: 101

Before: Refer to number 1 for the description.

After: It was a bit cold. It was hard and difficult to bend at first. However, as you continuously bend on the same spot, it kind of softens. My lab partner had a hard time bending it.

3) Paper clip cooled slowly

Number of Bends: 24

Before: Kindly refer to number 1 for the description.

After: It had this yellowy orangy faint colour to it. I think it's probably because of the heat that was applied to it. The heat, i think, caused chemical change. Surprisingly, while i was heating it, it didn't smell. I thought it would. When I was bending it, it was not as hard as the other clips. I think it's because the particles still had a little bit of space than usual due to the heat that was applied. It was easy to bend.

Questions:

Analyze p. 24

1. You compared the flexibilityof a metal wire that was heated and allowed to cool slowly with the flexibility of another that was cooled rapidly.

a) Which treatment resulted in a wire that was hard and brittle?

The rapid cooling resulted in a hard and brittle wire.

b) Which treatment resulted in a wire that was more flexible?
The wire that slowly cooled resulted in a more flexible wire.

Conclude and Apply p. 24

1. Write a short paragraph explaining the effect that hardening and heating can have on a metal?

Heating and hardening can affect the malleability of metal. If you heat a metal, its particles slowly move apart from each other and if it reaches the boiling point of the metal, it would turn to liquid. If you cooled the liquified metal very very very slowly, it will be hard and difficult to bend. However, if you slowly cooled it and took it when you felt that it was okay to touch even if there was a tiny bit of heat in it and bend it again, it would be flexible because of the heat left in it On the other hand, if you rapidly cooled the liquified metal, putting it in a cold water, for instance, it would turn out hard but brittle because the particles had no time to slowly stick together. The cold water quickly slows down the kinetic energy of particles, stiffening the metal.

Conclusion:

I thought the slowly cooled paper clip would be more hard to bend than the one rapidly cooled but I got the opposite results. We had different results than my other classmates. For my classmates, the slowly cooled paper clip was harder to bend than the rapidly cooled one. I think it was our fault why that happened. The rapidly cooled one had more time to cool than the one that slowly cooled. So, the one plunged in water had time for its particles to stick together again after being heated. Basically for the one slowly cooled, I just grabbed it when I felt that there was not that much heat in it and started bending it. It was easy to bend; easier than the rapidly cooled half. While I was bending it, the particles of that paper clip had a little bit space than usual because some of the heat was still trapped inside so it was still a bit flexible and easy to bend. I am contented with the results we got because we had a unique result! During this experiment, I learned that even a little bit cooling time difference between the two halves of paper clips would give us a totally different result.