At this stage of the lab we are putting the Cu(OH)2 onto a hot plate. This causes the Cupric Hydroxide to react with the heat and create Cupric Oxide (CuO) and Water (H2O). While constantly stirring, the mixture slowly gets darker and darker, eventually turning black altogether, creating Cupric Oxide. As you can see in the video, we are stirring the mixture while it is on the hot plate to prevent it from 'jumping around' as would happen if the water vapor was unable to evaporate through the solid precipitate at the bottom.