In Norway the usual age for starting to play the cornet (nobody starts on trumpet over here - trumpets are too long for those small arms) is 8 years. I currently teach 11 beginners of this age. One girl lost her front milk teeth this fall, and she asked me the question: - Do you know what the trouble is loosing your teeth when you play the cornet? I didn't, so she told me: - You get so much spit into your horn!
The first lesson is very important. If I manage to teach them to hold the cornet correctly with the finger tips on the valve buttons, and to buzz/blow without puffed cheeks, very much is done. I draw a mark on the inside of the right thumb, beside the nail, and tell them to hide the mark under the mouthpiece tube. That is to prevent them from stickinge the thumb too far in, and thereby resting the inside of the hand on the mouthpiece tube.
To demonstrate the necessity of this, I first play some quick, sloppy, "unclean" chromatics for them using the middle of my fingers on the valve buttons, and then some nice chromatics using the fingertips on the valve buttons. Then they get the point.
Counting and understanding the duration of the different notes is another issue. None of my 8-year olds understand what it means that a crotchet lasts one fourth of a semi breve. I never the less ALWAYS try the pizza model, (If you cut a pizza in two, one piece is a minim. If you cut a pizza in 4, one piece is a crotchet. If you cut a pizza in 8, one piece is a quaver.) and they think they understand, but they don't really. I check by asking: how many quavers fits into a denim? Bahhh.... Next year I repeat the model, and by the time they are 10, they have developed their maths and understand division.
To teach them to think-count, (I play together with my students, so I am prevented from counting aloud "one-two-tree-four" when they play.) I tap my left foot on their right foot as we play. Then they get the sense of the beat. They soon learn to tap their own foot, and then the problem is solved. Most 8-year olds feel safe by this type of physical contact, so this is a side benefit.
8-year olds also adore tunes with syncopated rhythms. To teach them this, I sing the rhythm while I tap 1-2-3-4 inside their hand a couple of times. This always works.
Teaching 8 year olds is a wonderful experience. They are still a part of the magic world of childhood, but they are receptive like little sponges, and just accumulate everything you can teach them. They are also so thankful. The way an 8 year old says "Thank you!", when you teach him/her to pull in the stomach to get the air out quickly to get an "impossible" new "high note" in one of the christmas carols, is really rewarding. Their joy of performing a favoured tune correctly, is very inspiring!