Rules that should be followed when heating a test-tube:
1. Never have the test-tube more than half filled with
liquid.
2. Always use test-tube holder and never tongs or your hands.
3. Don’t hold the test-tube upright in the flame, instead have it inclined at
an angle. An upright tube is more likely to spit the liquid out when it starts to boil.
4. Keep the test-tube moving as it is being heated, by moving your wrist from
side to side, to prevent bumping due to overheating.
5. Remove the tube temporarily out of the flame when the liquid starts to boil
vigorously or reduce the flame, so the liquid will not spill out.
