Rivendell Related Science Project Ideas

[Frank]

My 6th-grader is interested in developing a science project (6 week duration) which involves the bicycle. The Rivendell content requirement is satisfied, I believe, by acknowledging (and appreciating) the legacy of thinkings, writings, and musings accumulated and evolved by Grant and the rest of the team at RBWH which have accumulated on the web site, in the Reader, and now on the Internets over the years. 

The foundational question to be defined and ultimately answered is "What is the effect of_________on________? The first blank is a manipulated variable (perhaps tire pressure, clipless pedals, steel, other), with the second blank defining what is to be measured (speed, power, durability, etc.). Since multiple trials will be involved with controls, and the output will be an audio-visual presentation, sign boards, and quantitative data results, he'd like to do something interesting and less obvious than "flat tires roll poorly". 

The folks on this forum always impress me with their interest and insistence on getting to "why", so if any of you have an idea for a bicycle related (the more directly related to Rivendell and their ethos, the better), project, or a question that might be answered by an eager kid with time, tools, enthusiasm, and a love for his bike, I'd appreciate hearing your ideas.

And thank you.

[Stonehog]

Crank length on comfort?

Mobile Brian Hanson

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[Jim Thill - Hiawatha Cyclery]

Destructive testing in some way could be fun.

A cheaper one would be to test the effect of handlebar height on speed (aerodynamics). Find a big hill to coast down multiple times with the handlebar at different heights. Most cycle-computers have a max speed reading. To be consistent, put the hands in the same place in each test - I'm thinking resting on the hoods with the elbows bent in a normal, relaxed way, or on the hooks in a full aero tuck, or, heck, try both. Try also to conduct all tests at consistent air temperatures and pavement temperatures and no wind conditions and keep tire pressure consistent. Plot max speed vs handlebar height (stem protrusion or height from the ground?).

Then plot max speed vs handlebar height. Maybe max speed squared vs height. Try to find a relation that gives a straight line on the graph. The slope of that line would be a useful coefficient relating stem height to speed - i.e. for every cm higher the stem is raised, you lose x kph or kph. MS Excel is common software that does curve fitting and will give you a slope and intercept of your line.

[David T.]

How about the effect of tread on traction? He could compare a slick tire to one with a tread, maybe in wet and dry conditions. There are  different ways you could measure "traction", some methods wouldn't even require riding a bike. The challenging part would be for him to define what he meant by traction, and devise a way to measure it.

On the other hand, at the grade six level maybe you should just let him come up with the question, no matter how simple it is? My son has done these kinds of projects, I had lots of ideas of my own but I let him think of what he wanted to test, then asked him questions about how he would do it. He was happy to do the project that way, because it was his own idea.



 

[Jim Thill - Hiawatha Cyclery]

Actually the flat tire thing could be interesting. Similar to the aerodynamic test, you could try testing at different tire pressures. Obviously, at super low pressures the tires will roll worse on good pavement than they will at super high pressures. But say max tire pressure is 100 psi. What, if any loss, can we expect at 90 psi or 70 psi? What happens if we go to 120 psi? Is there a compelling reason to pump the tire to max pressure (or beyond)?

[Lee Chae]

Hey Frank. What a cool project! My two cents: I think projects with
really defined questions and applicability are the most compelling.
Also, simple is good, with clearly measured inputs and outputs. Off
the top of my head, I'd say one compelling question for 6th graders
would be: What's the effect of rain on braking? It has clear
applicability in terms of student/child safety, with direct
measurements and interpretation, and the experiments would probably be
a blast to perform.

A basic setup is a bike, bike computer, measuring tape, and chalk to
mark the stopping point. Have the rider get up to a specified (safe)
speed and apply the brakes at some established marker, then mark where
he/she stops, and measure and record. Do a number of runs. Then, do
the same in rainy conditions. If there's no rain in sight, do the runs
with watered rims and brake pads. You can even get your kid's friends
to participate to control for differences in rider weight, hand
strength, and reflexes. As a bonus, there are some solid, very basic
statistics you can get into here, too--but I'm not sure what is
appropriate for the 6th grade level.

Anyway, utlimately, the question partially addresses something
important to every 6th grader (I hope!): What should I be careful of
when I ride when it's wet out?

Best,
Lee
SF, CA

[Frank]

Thank you for the ideas, everyone. I'll have Graham read-through them, and I'm certain that your input will spark something. This is the brainstorming phase, and part of the process is to find external resources that can expand thinking, and ultimately horizons. The cool thing about being a sixth grader is that (speaking of curve fitting, Jim) the onset of experience curve and the erosion of innocence curve haven't yet intersected, so there's ample room to openly consider the input of others while contemplating your own ideas. 

David, you're correct; it's important that the idea is his, and his alone. He initially wanted to do something with either the bicycle or baseball and velocity, and considered an experiment related to the height of the mound (for those baseball fans, 1968 is the key to that whole idea) on ball speed, but decided there wasn't a good way to insure a clear control, so he moved on. 

Since we live in Seattle and he rides his Surly LHT with a Burley Nomad to school everyday, Lee's idea about braking in the wet is interesting. The safety and awareness tie-in is also great, and that's relevant with all of the ideas put forward here; it's important to have air in your tires and tread as well, particularly in the wet, eh? 

I'm also working with a group of committed parents at Eckstein Middle School to incent safe, utility cycling to school, and my son is involved in those activities. We just secured a SDOT grant for $1000, which we're using to rehabilitate a bike cage on school grounds, and we also promote "random biker day", giving a doughnut and a cup of hot cider to every kid who rides on that , and front and back blinking lights to those who need them. We're starting a bike train project with a student from the University of Washington at another Elementary school, and basically doing everything we can to make cycling fun, socially acceptable, and even "cool".

Thanks again for the ideas.

[Will]

I read downthread that he's using a Burley Nomad. So cargo testing might be in order.

If he can figure out some way to measure frame vibration, testing load locations and packing density would generate really useful and really interesting information.

Way back when, I had a newspaper route. Packing the baskets (front and back) had significant impact on handling. Stuffing the last 15 papers into the front basket vs. having a loose pack up front and using the rear baskets for those 15 papers created shimmy. Don't know why, but loads that could not "flex" were always more difficult.

Obviously the bike handled differently with front vs. back loads. Measuring frame response would be really interesting.

[PATRICK MOORE]

Years ago Mountain Bike Action used to test cheap Huffy mtbs to
destruction. You could do a timed stress test of a selection of some
of the cheaper brands -- need not be mountain bikes; Little Princess
bikes; Mad Max bikes; Winnie-the-Pooh bikes; what have you -- to see
which brands held up longest over the same off road route and stress.
This ought to be great fun if your child is a boy. MTBA also had a
Huffy tossing contest, IIRC.

More seriously yet, test different kinds, or qualities, or builds of
bikes over a single route under different riders to find out which is
fastest -- a measure of energy required and efficiency. For example, a
BMX bike versus a mountain bike versus a cruiser. The competitive
element ought to interest a boy and elicit any budding organizational
skills.

--
Patrick Moore
Albuquerque, NM
For professional resumes, contact
Patrick Moore, ACRW
http://resumespecialties.com/index.html