Take your child on a "listening walk". Walk around the street/park/shops and listen out for sounds you can hear. Then ask the child to report back what they can hear. You could also make a tick sheet of sounds you might encounter and tick them off as you go. Alternatively, take your child to an outdoor space and close your eyes to listen for one minute then discuss what sounds you could both hear eg. traffic noise, birds singing, wind blowing through trees etc.