Although I broke test tubes and played about with chemicals for fun, I did occasionally manage to obey the teacher's instructions as well; repeating experiments that others had long ago undertaken.
If you leave them lying on the desk they may roll off, so stand them in the test-tube rack.
The tube was shattered by the explosion.
He squeezed the toothpaste out of a tube.
Televisions with vacuum tubes are regarded as being behind the times.
5. When the reaction is over, place the test-tube on a damp cloth.