Small scale ship disappearing experiment

Recently I drove across a large cable-stayed bridge (~1.4 km) which is built as slightly arc shape. You can see the slight bend from these images (http://en.wikipedia.org/wiki/Stonecutters_Bridge).

I observed the following:

-   If I drive slowly and let the car in front of me to leave me behind, I can clearly see the car in front disappearing from the bottom (wheel->body->antenna).
-   If I drive in a flat suspension bridge, I cannot see the car in front of me disappearing.

It shows clearly that having a round surface can be a reason for a ship disappears from the horizon. 
Does the FEers have any scale down (~1-2 km) experiment to show their optical illusion theory is true?

if you find a large flat area of about 300m you can set this up with a camera at about 12 cm off the floor and then place the object at 50-100-150~m. take photos and observer your findings on this scaled experiment. i always wanted to try this but i could never be bothered.

if you find a large flat area of about 300m you can set this up with a camera at about 12 cm off the floor and then place the object at 50-100-150~m. take photos and observer your findings on this scaled experiment. i always wanted to try this but i could never be bothered.

Can you please describe further about how to observe and what is the expected result of the observation?

e.g. what kind of object to place? size of the object?

Anything other than water is going to be susceptible to imperfections rendering the experiment invalid.  And even water suffers from waves, currents, direction of flow, etc.  Even though water isn't perfect it is the most dependable one.

Anything other than water is going to be susceptible to imperfections rendering the experiment invalid.  And even water suffers from waves, currents, direction of flow, etc.  Even though water isn't perfect it is the most dependable one.

Don't forget about the air temperature gradient near the surface of the water and the likelihood of any of a number of atmospheric refractive phenomena.

if you have access yo a gym or sports hall that will be best to use. this is a fun experiment only and as flatorange stated it will not be 100% accurate. try and do the experiment a 10th or 5th of the scale, this makes working out distances easier. i would recommend 10th scale but finding a 200m+ hall will be hard!

you will need;

when you have found the most suitable area set your 'ship' up at the furthest end. mark and note the distances at 50m intervals (10 or 25 m if scaling down). set your camera up at aprox the average human height to the scale at the furthest spot and take the best pictures you can at 1x zoom and 8x zoom and 16x zoom. do what you can with the zoom but its important you also add these. repeat these steps at the other distances. document as much as you can, including setting up the experiment and the time of day and year and how hot or cold it is. note as much detail as you possibly can.
prepare your findings and please document them here. you may see that ship sinking anyway because the floor could be uneven but post them anyway. like i said its just for fun and takes little expense to perform as you will already own all the items needed.

Like Markjo said.  It's easy to run into a mirage or refraction with water.  Anything flat can, or will, have this effect.  I've seen a mirage across the 20 feet of the deck at my dad's house.  Roads and gym floors probably won't follow the exact curve of the earth anyway. 

Here's a 7-8 foot high (maybe 9ft, I would have to go out and measure it) rock 0.67 mile /1.07km away viewed from an elevation of about 15 inches.  the opposite bank is angled from me, but directly behind the rock it's about 1.18km.  I took the pictures through a spotting scope set at 30x magnification.

Here it is viewed from about 3 inches.


Last time I was messing around there with my new water proof camera, I got some pictures of it from perhaps an inch above the water.  the conditions that day made for very minor waves, and a bit of refraction, as the rock was mostly visible, but compressed.  I did a few from a couple feet too, but I haven't compared them yet.  I'll post those tonight.  That camera only has a 3x zoom.

a gym is not meant to follow the curve of the earth. it is to simulate a flat earth.

Oops, I got it now.  I misunderstood what you meant.

In that case, using a long floor to simulate a flat earth, I wish anybody good luck in getting something to 'sink below the horizon'.

Also, in before TB comes along stating that perspective effect only works at 1:1 scale.

the floor will become an issue at this level as its hard to find a perfectly flat floor.

whats your opinion on scaling it down? is this a valid experiment?

Oops, I got it now.  I misunderstood what you meant.

In that case, using a long floor to simulate a flat earth, I wish anybody good luck in getting something to 'sink below the horizon'.

Also, in before TB comes along stating that perspective effect only works at 1:1 scale.

Yes, that is what i mean. Any 'sink below the horizon' experiement using long flat floor?

If someone said it only works at 1:1 scale, then please explain why it works at small scale for curved floor.

the floor will become an issue at this level as its hard to find a perfectly flat floor.

whats your opinion on scaling it down? is this a valid experiment?

Well, you can use a horizontally placed laser to measure each marking. 

Any large suspension bridge will be flat enough to carry out any such experiment.

yes, perhaps. will you be performing then then?

Quote from: 29silhouette on September 27, 2012, 02:11:25 PM

Oops, I got it now.  I misunderstood what you meant.

In that case, using a long floor to simulate a flat earth, I wish anybody good luck in getting something to 'sink below the horizon'.

Also, in before TB comes along stating that perspective effect only works at 1:1 scale.

Yes, that is what i mean. Any 'sink below the horizon' experiement using long flat floor?

If someone said it only works at 1:1 scale, then please explain why it works at small scale for curved floor.

It was a reference to this thread. http://www.theflatearthsociety.org/forum/index.php/topic,55752.20.html