If you’ve been following us on Facebook or Twitter you probably know that this past couple weekends we’ve been involved in Fife Science Festival. One of the things we were demonstrating was the effect that spin can have on an object. Spinning objects have something called ‘gyroscopic inertia’ – this means that when an object is spinning it resists forces, such as gravity or wind, that want to change the direction in which it is spinning. This applies to the change from smoothbore muskets to rifles; a rifle has spiral grooves running down the length of the barrel that force a bullet to emerge from the barrel spinning. These spinning bullets can fly much straighter and much further than the bullets fired from a smoothbore musket.
This idea of ‘gyroscopic inertia’ can be demonstrated with a fun and simple craft: the spinning paper plane. Though they don’t look much like planes, these paper tubes, if thrown with a bit of spin, will fly much further than if thrown without spin.
Here’s how you do it:
STEP 1: Fold paper so that about a quarter of the length is still visible at one end.
STEP 2: Fold the creased end up to the edge of the folded section. Repeat.
STEP 4: Unfold the last crease you made. Curl the paper into a tube, tucking one end into the other.
STEP 5: Fold the creased end of the tube along the line where you unfolded the paper in step 4 in towards the centre of the tube.
FINISHED! Now try throwing your paper tube without spinning it and then again spinning it. Does it fly better with some spin?
It can take a while to get the hang of throwing them and spinning them at the same time but keep practicing! It’s a lot like throwing an American football; you want to hold it in your hand with the heavier, folded end facing forward and spin it off the ends of your fingers as you throw it.
You can also see gyroscopic intertia at work in rugby balls and frisbees and lots of other things!