## 4.15.2012

### Surface Area Tin Man Project

I've never taught my area unit very well or went beyond basic area formulas that students have been learning for years. This year I heavily focused on composite areas and perimeters, surface area, and volume.

I did my first real project of the year (um, my career) on surface area.

Each pair of students built a tin man out of boxes, toilet paper rolls, paper towel rolls, Styrofoam balls, and cones. They had to use a formula sheet to first measure the surface area of the parts, showing all of their work for each part. Next they had to tape the parts together. The tin man had to have all parts attached and be sitting or standing on its own. Then I would give them the exact amount of foil they measured for, no more and no less. They had to cover their tin man as completely as possible without running out of tinfoil or having extra leftover.

After their project was complete, I had them answer twelve reflection questions about the project. I also created a rubric that they used to self-assess and then I used the same rubric to assess them as well. This was the first time I've ever used a rubric myself, and also the first time having students self-assess using a rubric.

The students worked hard and really enjoyed the project. It was complete insanity while it was happening but the students were so engaged and surprised by how little their tinfoil was and yet it still was enough. They finally figured out that math actually works.

I really didn't have the time to spend on this but measurement is a weakness in our curriculum throughout all courses and plus, they deserved it. This was my big crazy geometry class of 24 students who all hated the class because it was so loud and chaotic. I wanted them to have one good memory of this year and this class and I think I succeeded. I actually got this idea from my English teacher bestie who did it in high school. She hated math but that really stuck with her and I want to do something each year with my students that will stick with them that long as well.

I felt like they answered the reflection questions honestly and thoughtfully. My objective  was for them to summarize their learning throughout this process. I think it was a good way for them to switch from active, hands-on builders to serious, reflective thinkers. I also think I need to add something into the rubric about how much work they did. In one instance, a girl did all the work and the boy was just getting supplies and doing whatever she said. But, he ended up with a higher grade than she did because he did better on his reflection questions. She was upset and I knew she would be. On one hand I understand. On the other hand, I clearly explained the things I would be grading on so she can't really argue with me. But I hated that she felt I was being unfair.

Overall, the project was a success and I will definitely be doing it again. My algebra I and II classes are totally jealous now and want to build one as well. Some students suggested that next time we create accessories as well or maybe even a heart. Cuteness.

Good times...

1. Thank you - I stole this as will many others.

I teach in hs - sophomores (right triangle trig, parabolas and imaginary numbers, circles, piecewise functions, exponents, and statistics [normal curves]) and juniors (matrices, polynomials, conics, logarithms, z-scores) and we are supposed to do this with projects when they do not have the foundation knowledge.

We are to turn their educational process over to them - they talk about TV.

I am struggling to make it relevant. I love math and don't think that conics - or logarithms - are the least bit relevant to someone who will never take calculus and thinks math is not necessary to their future.

Just blowing off steam.

2. This is an awesome idea! Thank you for sharing!

3. Ricochet,
Try turning over their educational process a little bit at a time- while you're still in control. I struggle with relevance too but let's focus on the learning more. How can we teach them to learn- observe patterns, make predictions, think critically, take risks, justify their thinking, etc? That's what remains relevant even when the math is not.

Jennifer,
If you try this I would love to hear about it!

4. Love this idea! It almost makes me wish I taught Geometry!

5. What a great idea! I love the idea of giving them something they'll really remember, too. Brilliant.

6. Did any pad their totals to make sure there was enough foil?

7. Mama,
From what I noticed, students rounded up on their measurements instead of being precise. That's really the only 'padding' I noticed. I wish I could have graded it on how much foil they used but I don't know how to keep kids from just wrapping it again to use up foil or throwing extra foil away or covering gaps with duck tape.

8. OMG, I LOVE it!

You can keep kids from "cheating" by giving them exactly one period to wrap it, with precisely pre-measured foil?

Mimi

9. how/from where did you collect the required materials? thinking of doing this on short notice and wondering from where I could gather all the bits . . . perhaps just styrofoam pieces from a craft store . . . hmm

10. Jason,
I just asked the teachers in the school and other friends to save theirs for me. I bought the styrofoam balls from Hobby
Lobby and made the cones out of paper. I bought the duct tape and tinfoil from the Dollar Tree.

11. I am super excited to try this. The reflection is 11 questions and I wondered if I missed one. Also, why DID we divide by 18? I must need to do the project too. Could you please help. Thank you so much.

12. Danielle,
I think I counted the first part where they have to list the formulas they used as the extra question.

We divided by 18 because the roll of aluminum foil is 18 inches long. So that would change depending on whatever length of tinfoil you use.

Let me know if you have any other questions. :)

13. I love this project! I'll link to it on my blog.

I agree with you on the tough situation with the one student. It can be hard, but you were upfront about the standards for grading and it was up to her to meet those standards and do what she could to get the best grade possible. Knowledge is important, but you also have to pay attention and follow directions. Including a part about how much you contributed to the project is a good idea!

14. Forgive me if this is obvious, but - was it tricky for your kiddos to wrap the styrofoam balls in foil? I can imagine that particular step might be frustrating. Tips?

15. I don't remember that one being any harder than the rest, although most students said the wrapping was the hardest part. I didn't really offer any help on that part. They struggled but they knew it was something they do so they didn't give up. Nothing really sticks out as far as tips except to cut as little as you can.

16. How much time did you allow to complete?I think that this is a great idea for a project.This year I have Geometry A & B and Algebra 2. I am always looking for project ideas that can translate to practical knowledge in Geometry.

1. I think it took about 5 class periods.

2. I like the way u taught

17. I love this project! How many rolls (estimate) of tin foil did you need for all the groups to do the project?

1. I think I went to the Dollar Tree and bought 8 or 10. I don't really remember but I still have some rolls left over so it didn't even take as much as I was thinking.

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1. I'm not sure where your comment went but class periods are about 47 minutes long,

19. what were your requirements for students finding the surface area for the sphere and cone?

1. I don't know what you mean? I gave them the formula. They had to measure and plug in the numbers to the formula.

20. Hi,
I am planning on doing this project with my geometry students and having them create 2d nets for each 3d object once they determine the surface area. Did you do this with your students? If so, how did you have them create the net for the sphere? I'm having a difficult time figuring out a way to introduce this in a way the will be able to comprehend. Thanks!

1. No ma'am, I've never taught nets before.

2. Okay, thanks so much!

3. My students had to come up with a plan for how they used the foil. I required they make a graph paper drawing to scale. The net of a sphere came up with every group. Some students researched how to make a net. Others decided they would calculate the SA and know that all the extra foil should cover the head. Some students created a net like a baseball is sewn on. The best one was a student figured out that a rectangle could cover a sphere if it was the length of the circumference and the width of 1/2 the circumference. I let the students give each other ideas and sent them to talk to people who had had success if they came to me!

The drawing the net part WAS super awesome, also having them create a scale version of the foil and how to cut it was great because they knew in advance where the waste would be!

21. Did you have them cover each part with tin foil before attaching to the main body part? I was wondering because if covered after it was assembled would make a difference in how much tin foil was needed. I guess you could have them subtract the part of each body part that was covered up by another body part? For example, if the bottom circle of a cylinder is covered when attached, you would have to subtract it from the total surface area of the cylinder. Just clarifying...... I love this idea!

1. I had them cover it after it was assembled. My thinking was that then they should have more than enough which wasn't always the case. =) You can do it however you want of course or even use that as a way to differentiate.

22. Thanks so much....such a clever idea!!!!

23. thank so much

24. Thank you for this idea, I can't wait to do it with my 4 geometry classes!!! I have been collecting toilet paper rolls and tissue boxes for a week now (mom can't wait till its over so people at her job stop bringing the toilet paper rolls to her lol!)

I LOVE the idea of using a cone for the head, however, I cannot think of something that is a cone shape that is free or cost effective. I have about 100 students so buying styrofoam cones will get costly even in grouts of 4...any other suggestions? Otherwise I will have to use another rectangle and I am trying to avoid that.

THANKS AGAIN!!!

1. A colleague of mine cut them out of construction paper and then taped them together to make a cone. I can't give better directions than that because I don't know how to do it myself!

2. Having the students make their own cones (with a compass) is a great way to help them realize that the radius of the partial circle is the lateral height of the cone in the formula. Then they have to measure the circumference of the cone to find the radius. There was SO much discovery possible in this project! And so many ways to differentiate! I seriously love it so much!

3. I used party hats from the dollar store...8 for \$1.00

25. Hi! I love this project and am planning on beginning it in my classes in a couple of weeks. A couple questions for you-

1) Did students lose points for not having enough tin to cover their figures? Is this just in the "completeness" section of the rubric? I would like to weight this more but don't know how to do so where they would not be able to pad their totals, etc.

2) Where did you get their final scores? From the self-assessment or did you complete a rubric for each student also? Did you feel like their self-assessments were fairly accurate?

Thank you so much for this wonderful resource! :)

1. 1) Yes, I only took off a few point for not having enough. It is hard because if they have too much, they can tear it off and throw it away. What you could do is call one group up at a time to cover there's in front of the class. But of course that would take longer.

2) The final scores came from a rubric I completed. I looked at their and made comments but gave my own scores. I thought they were fairly accurate but some rated themselves higher on working with partners than I would have.

2. Thank you so much! Was the rubric the same rubric that they used to self-evaluate?

My principal suggested I give I offer a couple points bonus if their score is within a 5-point range of my score.. hopefully this will make them answer honestly :)

3. Yes, the rubric was the same.

26. Hi there. I am looking to do this with my HS SPED students and was just wondering how many boxes of aluminum foil you went through, as well as, what size Styrofoam balls did you use?

1. I used these 3 inch styrofoam balls (I think) from Hobby Lobby http://shop.hobbylobby.com/products/3-styrofoam-balls-600981/ and I bought foil from Dollar Tree so I think I used maybe 3-4 boxes?

27. This was an AMAZING project. Thank you for sharing! I added in some conversions and scale drawings and required students plan for and account for over/under foil requests. They were so into it!

Also for supplies for 45 Tin Men took me 4 boxes of foil, and got 3 for \$1 wiffle balls at dollar store. Most expensive was the double sided tape I provided. I already had glue guns and they used those to put together. Thank you again!

1. I'm so glad you liked it! It sounds like you really increased the rigor. I never thought of using glue guns- seems like it would melt the foil. Double sided tape is another great idea!

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29. This is such a great idea and it is so cute! I am a 2nd year High School teacher!

How long did it take your students to complete the project? How many days?

1. 3-4 days the first time, then more like 2-3

30. I am doing a version of this in my class right now - such a great idea, thank you so much for sharing!