Checkout this video to see how can you cut a glass bottle without even touching it by using water and cooking oil.

Reason: The science behind this is the difference in temperature, as the heated blade touches the oil surface, the oil get heated and start transfering heat to glass and due to this glass start expanding, but lower portion which is dipped in water is at lower temperature and hence it doesn’t expand in proportion to the upper part which is surrounded by oil and due to this the glass get cut at that point.