do you notice what makes tummys go up and down?

Question

i have a three year old son daniel and when we watch movies he sits on my lap i notice his tummy goes up and down

Answer 1

Breathing properly. Kids do it. Adults tend not to. (I'm a musician. Vocalists really care about these things.)

Answer 2

Children are ...belly breathers...meaning that they do not expand their diaphragms when they breathe...they let their stomachs do the work instead....This will change with time.