The year 2 children were exploring nouns and trying to work out when to use a or an at the front.
Through trial and error, we found words which needed an: An egg, an orange, an ice cream, an umbrella, an ant, an x-ray, an apple.
We looked at the mouth shapes we make when we say sounds and realised that some of them are open mouth sounds; 
a,e,i,o,u or A, E, I, O, U. The children were told these are the vowel sounds.
The children were then asked to come up with a reason why some nouns had a and some had an. The children looked at what the nouns with an all had in common and the class worked out that if a noun starts with a vowel, it needs an at the beginning.
This is inductive learning, looking for patterns to find new rules. It is more of a challenge to discover your own new rules than just be told them but the year 2 children now feel really proud about what they have learned for themselves.