These are images of the frozen Delta Lake, NY during winter. To take these images, Farah stood on the lake! The frozen upper layer is a few inches thick--thick enough to support a truck. If you think about it, you may wonder: why isn’t the whole lake frozen from top to bottom? Why do only the top few inches of Delta Lake freeze? It is because the ice layer on top is an insulator and so it prevents the heat from moving from the liquid water below the frozen surface into the cold air above the lake. And why does the ice stay on top? Because when the water freezes, it becomes less dense than the liquid water below, so it floats on top. Credit: Farah Hamati.