# B Would it be possible to make something float?

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1. Jan 10, 2018

### doglover9754

While waiting in the doctor’s office, I looked at a ballon sticker on the wall. That made me think (once again). Would it be possible to make something float without using your basic flotation stuff (helium and propellers mostly)? I was thinking in more of a futuristic themed way. Like magnets, would it be possible to make something float by reversing that “force” (I’m honestly not sure what the reaction is between 2 magnets so I’ll just call it a force for now)? I’ve seen magnets float because you put 2 positives together (I haven’t done that experiment in a while so please forgive me if I’m wrong) and then one floats on top the other. Would that be possible for gravity (here I go again with gravity... heh heh. Sorry for all of you who hate my questions)? I was just curious that’s all. I pretty much need a yes or no kind of answer just to clear up my question (no need for a scientific explanation because I just finished school and my brain is fried). If anyone could help me, that would be awesome as usual! Thank you to all of you who put up with this kind of stuff (I’m sure it’s tiring to read all these kinds of stuff everyday)! Also, I’m not sure what prefix this would fall under so please bear with me if I’m wrong.

2. Jan 10, 2018

### Staff: Mentor

We already have trains that "float" themselves above the rails using magnetism. We call it maglev. https://en.wikipedia.org/wiki/Maglev It is pretty cool.

But floating on water. What do you think is the difference between something that floats and something that sinks?

3. Jan 10, 2018

### Khashishi

If you just put a magnet over another magnet, it could float momentarily, but it won't be stable. You can stabilize it using active feedback or superconductors or a simple physical rod.
See https://en.wikipedia.org/wiki/Magnetic_levitation

4. Jan 10, 2018

### doglover9754

The density of the object?

5. Jan 10, 2018

### doglover9754

I was just thinking of making floating cars. Dumb idea huh? This is the kind of stuff that I get quite often... ideas that don’t seem realistic sometimes.

6. Jan 10, 2018

### Staff: Mentor

Look up "maglev" (short for magnetic levitation). There are trains running in S. Korea, China, and Japan that use this technology.

7. Jan 10, 2018

### phinds

glass floats on mercury. glass sinks in water. glass density = glass density. Want to try again?

8. Jan 10, 2018

### doglover9754

Glass floats on mercury?! I never knew that!!!

9. Jan 10, 2018

### doglover9754

Um... one floats and one sinks??? That’s all I’ve got for now...

10. Jan 11, 2018

### lekh2003

You can read up on buoyancy, it isn't very difficult. Objects with lower densities float in higher density liquids. The glass on Mercury observation occurs because Mercury has a higher density than glass.

11. Jan 11, 2018

### DrDu

12. Jan 11, 2018

### doglover9754

I sure will! But I was leaning more towards flotation without magnets. The rails of the trains are magnetic an the bottom of the train is also magnetic right? I heard that somewhere... would it be possible to reverse gravity? Kinda like how you reverse magnets (positive and negative sides). I mean, reversing gravity would mean that things would just float right? Would there be a solution to making a limit to how high it can float above the ground? That’s the kind of stuff I was looking for but I think I have a better idea of how this “reaction” works. Thanks!

13. Jan 11, 2018

### doglover9754

Ahhh. So it was density!

14. Jan 11, 2018

### doglover9754

@lekh2003 I said that above lol

15. Jan 11, 2018

### lekh2003

16. Jan 11, 2018

### davenn

currently, only in science fiction

17. Jan 11, 2018

### sophiecentaur

Going back to that balloon: You can support a low density object with Electrostatic forces. We have all (?) done the trick involving rubbing a balloon on our hair or jumper and found that it sticks to the ceiling. Electric forces are immensely strong at small distances (they keep solids from coming apart under stress). Unfortunately (you could say) these forces fall off very fast with distance so actually getting something to 'float' at a significant distance from a surface is hard to achieve. A high voltage generator (several tens of kV DC) would achieve this but you would need some feedback arrangement to control the Volts or the object would stick to or fall off from the surface. This is also true for magnetic levitation in most cases (except where you can use a superconductor over a magnet).

18. Jan 11, 2018

### Staff: Mentor

It is time to learn some of the rules here @doglover9754. Your not allowed to say "I heard somewhere". On PF, you must give a link to where you read it, so that we can see exactly what it says.

19. Jan 11, 2018

### Staff: Mentor

It seems the thread has run its course with several good answers and advice. Before it will turn into a chat room, I'll close it now.