Direct Current on the oscilloscope

 I connected a battery pack up to the oscilloscope to show my class that the voltage doesn't change as time goes by with direct current. I then swapped the connections round to show that you then get a negative voltage.

 I did remember to pull the connections out completely to show that zero Volts is a line across the middle.

 But I did have to remember to flick the switch onto DC setting to get the oscilloscope to recognise what I wanted it to do.