Friday, June 29, 2012

BioX Kids Day 2012 - Elbows Booth Recap

Holy Moly - I never thought I'd get around to this posting (I've been running nonstop since the event).

I had so much fun at Stanford BioX Kids Day 2012, on June 15th.

Here I am in my booth slightly before the event started.  They even gave me a super cool mad scientist shirt (which you can't really see, but trust me, it's awesome).

Anyways, that was the last time you'd be able to see me over the crowd.

It was so nice of the event coordinators to offer us ice cream (it sat on the corner as shown in the pic below for 2 hrs before I tasted the ice cream soup and threw it away).  I was explaining the elbow model to over 150 young kids over the course of 4 hours.

I had an awesome helper, Steve, shown behind me

Here's the original post for the elbow lesson I did, modified slightly to make it easily understood by younger kids: Biomedical Engineering Elbow Modeling (please note, that the idea for the project is in no way my idea see pg 16 of this lesson for where I found the idea).

How the lesson went (and increased in complexity depending on the age and interest level of the kids - which ranged from 2-18 yrs old):
  • I asked to see the kids' elbows and then asked how many elbow each person has.
  • I asked if they knew what muscles are and if they can show me their muscles on their arms
    • I then tried to relate their muscle size to Popeye (and encouraged them to eat spinach), but apparently Popeye is pretty irrelevant nowadays.  Sad.
    • I asked if they knew the names of the big muscle they were showing me (biceps).
  • I asked if they could bend and straighten their elbows.
    • I informed them that muscles only pull, which is a lot like what string does.  Have you ever tried to push something with a string?  It just doesn't work.  Period.
    • So if the biceps are big when you bend your elbow, what muscle is big when your arm is straightened?  This is a hard question (luckily, I have pretty large triceps for people to poke - they aren't super big in most little kids).  You can also talk about how many heads each muscle has for the older kids (biceps = 2, triceps =3).
  • Biceps bend the arm and triceps straighten the arm, all while pulling - if anything, this was a good take home message for the kids.
  • Now that we established the ground rules (biceps bend, triceps straighten), we assembled our elbow model:
    • Due to budget limitations, I went to the 2-ruler model - 1 ruler for the upper arm (humerus) and 1 ruler for the lower arm (radius+ulna).
    • There were two big holes at the end of each ruler.  Don't use the bigger holes (unless you find bigger brads, but I unsuccessfully searched for bigger brads).
    • The best holes to use for brad insertion were around the 2 inch mark.  Using a brad to connect 2 rulers made a simple hinge joint.  At this point, I demonstrated that it can open and close when I push on it.  Keep it open in an "L" shape.
  • Our model is missing the most important piece of the lesson (ie. what bends and straightens the elbow?). I made a brief introduction to the term "tendon," pointing out that tendons connect muscles to bones.  If you want to see a tendon, look down toward your heels.  Your Achilles Tendon connects your calf muscles to your heels and is a very tangible example of a tendon.  We have smaller tendons in our arms connecting our biceps and triceps to our arm bones, but it's all inside our arm and we can't see it.
    • To model a biceps muscle with a tendon, double knot a piece of string to a paperclip bent into a hook shape.
      • Attach the tendon to the lower arm, around the 10.5" mark on the lower ruler, and string the string through the 10.5" mark on the upper ruler (don't tie it or knot it since you'll be pulling on it).
      • Have the kids pull on the string.  Sweet, they just bent their elbow.
      • For the older kids, ask them if they could point in the direction of the force the muscle is generating (along the line of the string).
      • Now can they straighten their elbow?
    • To model a triceps muscle (another string + paperclip hook) is a little more tricky since you want it to still attach to similar locations in the lower and upper arm, but the force is supposed to be directed downwards (opposite-ish of the biceps muscle).
      • The trick here is making a joint capsule (lower friction environment) by directing the string through a paperclip which you stick on the back of one of the rulers.
      • Attach the hook to the lower arm around the 9" mark.  Thread the string through the paperclip on the end of the ruler (the end closest to the brad), and then thread the string through the upper ruler around the 9" mark.
        • At this point I want to point out that you should be holding your elbow horizontally, so gravity doesn't straighten your elbow instead of the triceps.
      • While the elbow is bent, have the kids pull on the string that is threaded through the 9" mark on the upper arm (the "triceps").  It should straighten the elbow.  If it doesn't, check that the hook on the lower arm for that muscle is directed downwards.  Then check to make sure your string isn't getting caught up with friction somewhere else.

I made a lot of these for the little ones, older kids, 5+, can do it on their own
Super cool elbow makers:

I held while they pulled their muscles
Father and son, learning about elbows together. 

**Note the exact location of the holes may vary depending on what kind of ruler you purchased (ie. adjust 10.5" and 9" as you see fit).  Even my two purchases from the same vendor (a few months apart) varied. We used these rulers: Charles Leonard Inc. Ruler, 12 Inch, Wood, 36 rulers


  1. That's cool that it was so successful! Sounds like you'll need more helpers for next year!

    1. Hi MaryAnne. Yes, very successful! Yes, I need more helpers and possibly a bigger table. Unfortunately, it was the Friday before graduation and 3/4 of the students who would help me out were involved in graduation and obligated to their families. My helper just happened to be a friend of the organizer and is getting his teaching credential. He jumped right in and ran with it; he's going to be an amazing teacher. All-in-all, I'd love to do Kids Day again.