Everyone knows the Earth is round. It’s been taught to us all since we came out of the womb. In fact, here’s a baby Onesie to show you what I mean:
Well, as strange as it sounds, not everyone believes the rhetoric regarding this 500+ year old spherical Earth idea. Something that really makes people skeptical is the amount of curve that is supposed to be there. Supposedly, we know the size of the Earth, therefore calculating the curve is easy as pie. (Not pi.)
Given the size of the Earth, you should see 8 inches of curve per mile squared. So, here are a couple of examples:
1 mile: 8 x 1^2 = 8 inches of curve
2 miles: 8 x 2^2 = 32 inches of curve
3 miles: 8 x 3^2 = 72 inches of curve
4 miles: 8 x 4^2 = 128 inches (10.67 feet) of curve
(Since the experiment used 4 miles for the test, that is a good place to stop. )
If you tell someone that a 4 mile stretch of water has a 10 foot curve, they will think you are wrong. Instinctively, they know that is wrong. They will assume that your equation is faulty or that you figured it out wrong, but in fact, that is the way to do it, and those figures are accurate. Research it for yourself: How to calculate the curve of the Earth (Google search).
This experiment was done by Jeran Campanella (youtube channel “jeranism”). His experiment was done in two videos. One from his side of the bay using UStream, and the other from the other side of the bay by his hired photographer, which was posted to youtube.
I took a screenshot from each one to make it easy to look at. Click the image to get a better view of the visible dot. It is difficult to see in the screenshot, however, when you watch the video, it is planely obvious that you can see it.
You’ll have to jump to around the 7 minute mark of this video to see the laser part:
On the youtube video you can jump to around the 4 minute mark to see from across the bay.
EDIT: This is his compilation of the two videos. Skipping ahead to 23 minutes will show the side-by-side videos from each side of the water, four miles apart.