- Hi.
Elsewhere on YouTube we've got a video
explaining the circle of fifths.
What is the circle of fifths,
what does it tells us, how's it useful.
So if this is something you do,
you might want to just look up that video
before you get involved in this.
We've also got some
other quizzes out there
on the circle of fifths
and some material that tells us
how to use the circle of
fifths in all sorts of ways.
So kind of a key thing,
literally a key thing,
because it's telling us
about keys for musicians.
So in today's little light hearted quiz
we have a circle of fifths on the board.
But you might notice that there
is some missing information.
So you may at this point want to pause,
have a look at what I've got there,
and decide where you think
the missing information is
and then when you can come back to me
I'm going to tell you where it is
and you can see whether
you've managed to spot it.
Okay.
Well if you've had a
chance to look through
let's see where we got to with this.
I'm going to start with the major keys
in the middle of the three
circles, the ones in black,
and the circle of fifths
on the right hand side
goes really nicely,
remember we're going up in fifths,
in perfect fifths to be precise.
But we seem to have a
missing key here, don't we?
So one thing that you should've inserted
is A major,
because A is a perfect fifth
above D, so there we are.
Now, are we okay otherwise
in the major keys on the sharp side?
Almost, but there's one
missing piece of information.
I wonder if you spotted this.
F major, nope, it's F-sharp major.
Why is it F-sharp major?
Because F-sharp is a
perfect fifth above B,
so we're doing the circle
of fifths in perfect fifths.
Also because we introduced F-sharp up here
which means that from this point onwards
any F we come across must be F-sharp.
From this point onwards
any C we come across
must be C-sharp whether
it's a major or a minor key.
So that's what's going on there.
Now what about the major
keys on the flat side?
Did you seem happy with that?
Was there anything missing?
Hopefully you spotted this.
This isn't E major, it's E-flat major.
It shows you how important it is
to get these flats and
sharps right as well.
Because look, E major's over here,
and E major's got four sharps,
but E-flat major is over here,
it's got three flats.
So it's a totally different key
even though it's got the same letter name.
And of course if we're going
to go down in perfect fifths
after the first F everything becomes flat.
You'll also notice that I've
got B-flat on the outer ring,
the next key is B-flat.
E-flat on the outer ring,
the next key's E-flat.
A-flat, A-flat, and so on and so forth.
So I think that deals with
some missing information
in the major keys section.
Now then, have we got
any missing information
on the outer ring which is
dealing with our key signatures.
Well if we look through here,
F-sharp, C-sharp,
G-sharp, D-sharp, A-sharp,
they're all looking fairly
sensible there isn't it?
So I don't think there's
anything amiss there.
When we go around here,
B-flat, E-flat, A-flat, D-flat,
G-flat, ah hah.
There's one missing.
So remember, when we're dealing
with the key signatures,
a new sharp is the seventh
degree of the scale,
a new flat is the fourth
degree of the scale.
So we need to have a
C-flat tucked in there.
So that was another piece
of missing information
which takes us on now to the inner circle
which is the minor keys.
Let's have a look around this side.
A, E, B, F-sharp, C-sharp,
G-sharp, D-sharp, A-sharp.
Seems pretty good to me, doesn't it?
What have we got here?
D, G, C, ah, missing key.
So to find the relative minor
you have to go down a
third, a minor third down.
So that's going to be F minor.
If you're not sure about
this minor third thing,
you know it's F and not F-flat minor,
because here we've got B-flat,
E-flat, A-flat, and D-flat.
It doesn't mention F,
so F must be natural,
so it must be an ordinary F minor.
And then we've another piece
of missing information down here.
So if I go down a third
from G-flat, I get to E,
but of course it's not E minor,
E minor's all the way up
here, look, with one sharp.
A totally different key.
So this is this thing with
all this flats, six flats.
Well is it E?
No, it's E-flat.
You see, E-flat was introduced here
so it must be E-flat
from that point onwards.
And if you know your intervals
you'll also know that E-flat
is a minor third below G-flat.
So that completes the missing information
in the circle of fifths.
So I hope you got on well
with that little experiment
just to see if your
circle of fifths knowledge
is completely sound.
