A surprising fun science fact is that the curve of the earth is detectable simply by standing up. This really only works with the surface of the ocean or a large lake, but it's something you can do at the beach. I recently gave it a go in a visit to Venice Beach near Los Angeles. With my Nikon P900 I held it close to the water level (about two feet up) and took a photo of a boat off in the distance. I then stood up and took another photo: And I did a similar comparison with a beachside hotel that was 11.2 miles away This difference here is just from me standing up. (The red roof is another building behind the hotel) I took several more photos and video, and will post them later.