1) why do we add salt to the ice?
To lower the melting temperature of the ice down.
2) why do we add the cookies and other things, only after the milk has frozen slightly
Because if we put the cookies first it will stick in and make bad taste.
3) what are two factors that affect the freezing you think?
Ice and salt.
4) why do you need a bit of air in the bag?
Easy to move around