I regularly speak to this age group at the planetarium in Perth, plus I've done lots of viewing nights with ASWA, so I've got a few tips for you that should work:
Keep it simple.
Don't fit in too much.
Focus on a few bright constellations - we always use the southern cross and the pointers and at this time of year include Scorpius and the teapot of Sagittarius. You don't need much else.
You might want to ask if they can see any patterns in the stars themselves - just let them make up a few random patterns (asterisms), it just gets their imagination going and helps them get the hang of constellations
They always want to know where planets are, so make sure you point out Jupiter. They might want to know where the others are, so be prepared: know that Mars and Venus are in the morning sky and Saturn behind the sun at the moment.
Don't forget the Milky Way - if you can see it.
Check before hand for any satellites, including the ISS and iridium flares, so you can get everyone to look up at the same time
Finding south using the cross
might be beyond them - you might have to try it and see, but when I first started doing it in the planetarium the mothers would come up and say "that was too technical for my little Johnny" (or thereabouts
). I was taught it around that age and got the idea, but not everyone does. Play it by ear, so to speak, and if confused noises come through drop it as quick as you can and move on.
The objects Dave mentions about are probably best. Keep them bright objects, kids don't tend to be impressed with the faint stuff - although the adults might be!
Keep it short, after an hour they usually get restless in my experience, and go off and run around in the dark. So keep it simple and don't try to do too much.