To make this simple bowl:
(UK abbreviations) readers in the US can substitute sc every time I have written dc.
Using a 4.5mm hook and a dk weight yarn. 100% wool yarn that is handwash only will usually felt but check when you buy it.
Make 5 dc into a magic loop.
Working in a spiral make a flat circle up to 50dc, as follows,
round 1: dc 2 into each dc around (10dc)
round 2: *dc 1, dc 2 into next dc, rep from * around (15 dc)
round 3: *dc 2, dc 2 into next dc, rep from * around (20 dc)
round 4: *dc 3, dc 2 into next dc, rep from * around (25dc)
spotting a pattern yet...?
round 5: *dc 4, dc 2 into next dc, rep from * around (30dc)
round 6: *dc 5, dc 2 into next dc, rep from * around (35 dc)
round 7: *dc 6, dc 2 into next dc, rep from * around (40dc)
round 8: *dc7, dc 2 into next dc, rep from * around (45 dc)
round 9: *dc 8, dc 2 into next dc, rep from * around (50dc)
round 10: dc into back of loop only around (50dc). Going into the back of the loop only creates a natural fold point for the start of the sides.
dc around evenly in a spiral until desired height is reached, I did approximately 15cm, remember that the whole thing will shrink when washed.
Put it in the washing machine on a hot cycle with a little soap (not as much as you would use for a normal wash. Mould it into shape when it comes out of the wash and leave to dry, drying can take a couple of days.
To make a smaller bowl stop increasing before you get to round 9 ( I would do at least up to round 4 or it will be extremely small once felted), do round 10 and then the sides to a proportionate height. To make a larger bowl, continue with more rounds, following the pattern of 1 extra dc per round, before doing round 10. Again make your sides in proportion to your base.
As an extra note - always remember to properly shut the soap draw before switching your machine on!