## Sunday, October 14, 2007

### Memory Wheel

In calculus, we just finished learning the derivatives of the trig and inverse trig functions, and in the learning log, one student asked if we could make something to help memorize all the formulas. We had gone over some tricks in class, but now they're faced with the daunting fact of memorizing (gasp) 12 things.

I came up with making a wheel like the one above, and after a trip to a craft store for some card stock and some small (are they called?) rivets, I made the one pictured. I quite like it, and it wasn't too difficult.

Steps:
1. Use a compass to draw 2 different size circles on card stock and make sure to mark the center.
2. Cut a "window" out of the small "top" circle (I used cuticle scissors, but I guess an exacto knife would work).
3. Join the circles with a rivet (it was doable with a hammer).
4. I used a sharpie to write the functions on the outside circle. I could fit 14 things with my handwriting. It seems more are possible.
5. Write the derivatives (or whatever the answers are) inside the window as you rotate it around.
6. Voila.

Now let's see how much class time I want to devote to this, or how much I can make them do at home. Everyone has hammers, right?

1. Not everyone has a hammer, but just about everyone could come up with something they could use in lieu of a hammer. :)

2. Anonymous4:11 AM

Well, I wasn't thinking. Even though people might have "hammer-like" objects, they still need the extra tool to put on top of the rivet.

3. You could use simple paper fasteners instead. (The kind where it has two "wings" that you separate after pushing it through the paper.)

4. Anonymous12:39 PM

That's a good idea. I did see some really small ones, but then I thought the rivets were too cool. It may ultimately be too much trouble, & I'll use those (wing thingies).

5. In scrapbooking, they are called eyelets, Just like on tennis shoes. I think they need special tools for joining.

Larger ones are called grommets, just like the animated dog.

I vote for paper fasteners, which may also be called brads.

6. MathTeacher449:15 PM

I was thinking that to make it even easier you could maybe use different sized/colored paper plates as the circles....no real cutting (except for the answer hole) involved! This just might turn into a class project! Thanks for another of your creative ideas!

7. Anonymous4:20 AM

Thanks, heidicrafts, I don't think I heard those terms before. The paper plate idea is also clever, mathteacher44. I guess I got all excited because these would look nice with the different color stiff paper and the rivets/eyelets make it turn really smoothly. It IS taking more class time than I'd prefer, so I'll have to rethink it next time.

8. MathTeacher448:23 PM

FYI, I tried the paperplates with "brads" today and it totally worked. I'm psyched! If I get really into it, maybe I'll email you a picture this weekend. :)

A couple kids saw it and thought it was pretty cool.

9. Anonymous8:30 PM

Hi Mathteacher44,

I finished the eyelet/grommet construction in class today. Tip: if you pound too hard and make it too firm, it eats through the paper, and then you end up using the brads anyway. I'm just saying :). I'm glad yours worked, and I'd love a picture.