Science fair project.

Ok so it’s science fair time. At my school’s science fair, you don’t build something and present it. You have to test something and present it. I’d love to do something yoyo related but it seems as though there are too many variables. There can only be one variable which I can manipulate and I have to observe how that variable causes something else to happen.

 The independent variable is the one I shall manipulate.

 The dependent variable is what the independent variable affects.

 After I find my question I must present a hypotheses in an if/then statement, or a conditional statement         if you will. 
 (i.e. If I change the response pad in a yoyo from IrPads to Flowable Silicone, then the yoyo will spin longer.)
 The only issue is that I don't know how to keep each throw under the same exact power. 

Any ideas?

You could maybe just drop the yoyo instead of just throwing it. Or you could attach the sting to a fixed point that is pretty high up and let it roll down and time the spin.

I would say that there are too many variables for you to test that hypothosis, if that is what you are doing. You won’t get good data, unless maybe you are Steve Brown or H. Suzuki or someone like that. You probably can’t throw consistently enough to collect good data. And you probably can’t sili a yoyo consistently enough to get good data. And you don’t know how well quality control on IR pads are to get good data.

I’m not saying you throw bad, or sili bad, or that IR pads or bad. I’m just saying that you basically have no controls to test against, and no controlled variables to monitor.

If I were you, I would discuss this with your teacher to make sure he/she thinks it is a viable experiment. I don’t know what grade you are in or who is judging your performance, so I don’t know exactly what could qualify as “good data” in this specific case.

Linear acceleration and velocity are really all you need to worry about unless you want to try and find an energy system to manipulate the yoyo.
If you don’t want to do all of that I would just drop them from a set height with equal lengths of string so their velocity is the same when the string catches. This would be the same because the acceleration of gravity is the only force acting on the yoyo falling down (minus drag from the air, which is so minimal for a science fair project I hardly doubt it will matter…lol otherwise you will have to create a vacuum.) Create a slide on a table where the yoyo’s can sit that are held and have like a paperclip which you can pinch to release the wood so they drop at the same time. I would calculate spin time from the second the release mechanism is engaged. Finding out the coefficients of friction of the response pads and the material of the yoyo you are using, as well as the string and then pre-calculating spin time would really be cool and probably get you mad props from your teachers.

LOL I have soooooo many ideas for yoyo experiments running through my mind right now you got a gold mine.

Let me know if you have or want any more ideas.

(if you use mine, I require you to do a full written article and submit it for peer review…or just youtube it so we can watch the experiment)

P.S. maybe come up with your own response pad that has a super low friction and try to get the longest spinning yoyo from a straight drop. Oh research and experimental design how I love thee…

You don’t necessarily need every throw to be the same to test this. You just need to measure a large enough sample of throws that the other variables are likely to cancel out. If you have ever done an experiment in class where you repeat the experiment multiple times and average the results to get a more accurate measurement, the same concept applies here. You just might have to measure a lot of throws to get an accurate estimate of the average spin time with each set-up. A rule of thumb is the more the measurements vary across individual trials, the more times you’ll need to repeat the experiment to get an accurate estimate. So if your throws with the same set-up are all within 10-20 or so seconds, you can use fewer throws than if some are a full minute longer than others. If you use a more controlled process like Mrjackthepoodle suggests, you will probably get a tighter distribution of results and won’t need to repeat the experiment as many times.

The main problem with this is it might end up being too much statistics for your grade level. A lot of school science experiments are designed for the random error from uncontrollable variables to be negligible so that you don’t have to worry about accounting for them. The results of this experiment could be hard to present without using statistical analysis to show that any random variables have been accounted for. It could definitely be done, though.

Just get all three benchmarks. And compare the shapes because all the other stats are the same.

Have 3 different bearings.
Drop the yoyo.
See which bearing tilts first.

Simple, common sense, but viable

The trick here is that you will encounter significant tedium in creating a controlled environment. Make sure you’re indoors. Tie the yoyo to a rod of some sort, measure the string length and cut precisely, use the same yoyo. You start with a fresh set of pads and a new string. You need a way to control for a straight fall from the rod, so maybe two pieces of wood with a dowel between them, allowing for a consistent, straight fall. You measure the length of spin, then repeat however many times. You then trade out for a new string and new response; Wash, rinse repeat. It’s tedious, but allows for the control over straightness of throw, falling speed, string length and new vs old string, accounts for changes in the response over time, and minor differences between even the same model of yoyo. And if you’re doing a fairly small test, such as 20 spins, and get fairly consistent numbers, a simple average would work fine. Unless, of course, you’re learning about t-tests and other experimental statistics. These things get way too complicated, way too quickly.

You could do the spin times with different Yoyo bearings konvave, gold plated, trifecta curved bearing, 10 ball bearing, 8 ball bearing, flat bearing. Lots of options.

you could attempt to determine the formula for string length to spin time for a specific yoyo from a drop. That would actually be pretty interesting to see how much the length effects the spin time.

I think that’s a great idea, simple and easy math to show how height affects vertical velocity. You could even do different size yoyos to show how mass is a factor.

Lol so many responses I think the op is overwhelmed.

Well, I’m with ya. I need to find one soon.

I was thinking that the easiest thing to show is how important weight distribution is and how easily it can get out of balance. You could show with a pretty simple drop with just gravity how stable a yoyo is and then put a small amount of putty (1 gram) on one edge, then both, then two on one edge, both, etc and use a camera at a fixed distance to capture how out of true the yoyo might spin at these varying sets. From there maybe an example of real world applications on car wheels getting balanced.

now just learn physics lol with the theoretical calculations of rotational motion haha