Use an app like Noise Down which will automatically sound an alarm when the decibel level gets too high. | 37 Insanely Smart School Teacher Hacks
1913 - After parcel post service was introduced in 1913, at least two children were sent by the service. With stamps attached to their clothing, the children rode with railway and city carriers to their destination. The Postmaster General quickly issued a regulation forbidding the sending of children in the mail after hearing of those examples.