I've mentioned this once before but since we're talking about measuring the curvature of the Earth I thought I'd bring it up again.
A really good experiment to measure the curvature of the Earth, that anyone could do with minimal expense is this...
Find a lake. Pretty much any lake will do but the ideal lake would be one that is sheltered from the wind and has little or no boat traffic on it so that there is as little wave action as possible. What we want is a nice flat stable surface.
In addition to being flat, it would make things easier if it wasn't very big. The reason I say that is because we're going to shooting laser pointers across the lake and the further away you get from shore, the more difficult it's going to be to get things lined up right. The thing that'll make this much easier is if you can have easy access to both sides of the lake.
So, once a suitable lake has been found (There's a perfect one right down the street from by employer's house!), then the first step is to set up a target on the far side of the lake. The more reflective the better. (I have a big Deer Crossing street sign in by garage that would be perfect because street signs reflect light straight back to the light source no matter which direction the light comes from.)
Then, go to the other side of the lake very near where you intend to launch your boat from but in a location that is in direct line of sight to your reflective target. Here we have to set up our laser pointer. It is critical to make sure that the laser is set up on stable ground and that is it pointed directly at that target across the lake AND that it is absolutely as close to perfectly level as you can figure out how to make it. This perfectly level part is, by far, the most technically difficult part of the experiment to achieve. I envision the use of plumb bobs and some sort of pre-made apparatus that will hold the laser securely in position but there are lots of ways to achieve this. Be creative!
Once your laser is set up properly and pointed at your target across the lake, the next step is to set up a target on the boat. This target needs to have some sort of graduated lines on it so that a measurement can be made, so a ruler or graph paper or whatever. Also make sure that it is a color that makes it easy to see the dot from your laser pointer, so no red targets unless you're using a green laser.
Once you have the target secured to the boat, the next step is to get the boat as close to your laser pointer as possible while still being on the surface of the water. Move the boat slowly and move around on the boat as little as possible so as to keep things as stable as possible and once you get the boat into a position where the laser is hitting the boat's target, take your first measurement by marking where the target is being hit. If your target it adjustable, you can adjust it so that the laser hits a specific place on your target but either way, you want a good measurement for where the laser line is on this side of the lake. Every move you make on the boat is going to wobble things around so filming this and pausing the video later may be the most accurate way to take the measurement.
Now that this measurement has been made, head across the lake and find the laser dot over there. This is where your target on the other shore is going to make things much easier! Once you find the dot and stabilize the boat as much as possible, make another measurement.
The curvature of the Earth is 7.98 inches per mile, so if you're even as much as 1/4 mile from the laser pointer, the dot should be about 2 inches higher on your boat target because you've dropped two inches due to the curvature of the Earth. If so, you will have empirically proven that the surface of large bodies of water are not as flat as they look to the naked eye and that the Earth is, in fact, a sphere.
I hope, unbelievably, to do this experiment myself. If I do, I'll certainly post my results here. Ideally, I want to film it and maybe post the whole thing on YouTube, which would be super cool, regardless of the results.
Clete
A really good experiment to measure the curvature of the Earth, that anyone could do with minimal expense is this...
Find a lake. Pretty much any lake will do but the ideal lake would be one that is sheltered from the wind and has little or no boat traffic on it so that there is as little wave action as possible. What we want is a nice flat stable surface.
In addition to being flat, it would make things easier if it wasn't very big. The reason I say that is because we're going to shooting laser pointers across the lake and the further away you get from shore, the more difficult it's going to be to get things lined up right. The thing that'll make this much easier is if you can have easy access to both sides of the lake.
So, once a suitable lake has been found (There's a perfect one right down the street from by employer's house!), then the first step is to set up a target on the far side of the lake. The more reflective the better. (I have a big Deer Crossing street sign in by garage that would be perfect because street signs reflect light straight back to the light source no matter which direction the light comes from.)
Then, go to the other side of the lake very near where you intend to launch your boat from but in a location that is in direct line of sight to your reflective target. Here we have to set up our laser pointer. It is critical to make sure that the laser is set up on stable ground and that is it pointed directly at that target across the lake AND that it is absolutely as close to perfectly level as you can figure out how to make it. This perfectly level part is, by far, the most technically difficult part of the experiment to achieve. I envision the use of plumb bobs and some sort of pre-made apparatus that will hold the laser securely in position but there are lots of ways to achieve this. Be creative!
Once your laser is set up properly and pointed at your target across the lake, the next step is to set up a target on the boat. This target needs to have some sort of graduated lines on it so that a measurement can be made, so a ruler or graph paper or whatever. Also make sure that it is a color that makes it easy to see the dot from your laser pointer, so no red targets unless you're using a green laser.
Once you have the target secured to the boat, the next step is to get the boat as close to your laser pointer as possible while still being on the surface of the water. Move the boat slowly and move around on the boat as little as possible so as to keep things as stable as possible and once you get the boat into a position where the laser is hitting the boat's target, take your first measurement by marking where the target is being hit. If your target it adjustable, you can adjust it so that the laser hits a specific place on your target but either way, you want a good measurement for where the laser line is on this side of the lake. Every move you make on the boat is going to wobble things around so filming this and pausing the video later may be the most accurate way to take the measurement.
Now that this measurement has been made, head across the lake and find the laser dot over there. This is where your target on the other shore is going to make things much easier! Once you find the dot and stabilize the boat as much as possible, make another measurement.
The curvature of the Earth is 7.98 inches per mile, so if you're even as much as 1/4 mile from the laser pointer, the dot should be about 2 inches higher on your boat target because you've dropped two inches due to the curvature of the Earth. If so, you will have empirically proven that the surface of large bodies of water are not as flat as they look to the naked eye and that the Earth is, in fact, a sphere.
I hope, unbelievably, to do this experiment myself. If I do, I'll certainly post my results here. Ideally, I want to film it and maybe post the whole thing on YouTube, which would be super cool, regardless of the results.
Clete
on't worry, it won't
