How will you show that metals form basic oxides?

when metallic oxides react with water they form metallic hydroxides which are basic in nature.to show that these are basic in nature,we should conduct a litmus paper test.in this experiment,we will observe that red litmus turns blue on coming in contact with them. this shows that metallic oxides are basic in nature.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me