Help me with my science project on yoyos! {merged}

The experiment seems ok, but I don’t know how well it will really translate to real yoyoing.

It shouldn’t matter as long as you mention it in your paper, like the exact string length, the yoyo specs.

One thing that you need to do is balance the yoyo by twisting the string when it’s spinning, so the yoyo body does not touch the string AT ALL. This is important because the friction between the string and the body will kill spin time a lot more than the friction inside the bearing. The yoyo should not stop because of the string rubbing the body, but rather it has to stop from the friction of the bearing itself.

Also try to use the bearings of the same company or at least similar quality if you can, because any allegedly ‘better’ material with bad manufacturing will most likely perform worse than the ‘lesser’ material made in high standards.

Okay, but I’m still confused on the whole throwing it hard thing. If the steel spins for 12 seconds and the ceramic spins for 18, can I say it is 50% better?

For your particular scenario and method, yes. Maybe not ‘50% better’ as it’s too broad, but more like ‘it spins 50% longer therefore the better choice’.
It doesn’t have to answer every possible scenario, as long as if other people do the same experiment with the same method they get identical results. In the future you or someone else may use a different method and then have a different result, it’s okay. You can then say that this new method is more accurate and closer to real world scenario because this and that, things like that.

Thanks mate. I appreciate your time.