Write the next sentence in the following story.

How to supercool water
Gather the necessary materials.
For this method, you will need salt, purified water, a small clean glass or plastic cup, a large bowl, and ice. If you have a thermometer it would also be useful, but not necessary.
Make sure your glass is very clean; any impurities can cause the water to crystallize into ice before supercooling occurs. The bowl must be large enough to contain the glass and enough ice to submerge the glass.