They are all aged between 6 and 10. Can’t really believe this.
This incredible DIY footage shows just what your guitar or violin strings look like when you play them.
Guitar strings wobble very strangely
So, you're playing the guitar, merrily unaware that you're creating some seriously weird shapes with the strings you're plucking. Like this:
Take a look at what this guy shows us, with only his iPhone and an acoustic guitar:
You know what? It works for violins too!
It's not just the finger-picking likes of casual guitarists that can enjoy these sonic lovelies - the string section can have exactly the same amount of fun. Look!
Now take a tour of this string quartet - you can see how lower strings and plucking produce different oscillations to higher bowed notes.
The good thing about these videos is that they were made on perfectly normal cameras that anyone can use, even if it's just your iPhone.
So why not get your battered acoustic out of the cupboard and pop your phone inside?