After losing the seniors, we worked on a neat lab that I used to use when teaching meteorology. I used it to show how warm and cold air met along a frontal boundary. I used it today to reinforce how ocean water density is affected by temperature. The students loved the lab. Lots of Snapchat videos and photos of the warm water sliding over the sinking cold water and smiling students. They replaced the divider and then mixed one side to create warm purple water. They were so interested to see what happened when the divider was removed and were amazed when it wedged between the red and blue water.