# Does anyone know a video where a calculated model is compared to physical reality?

1. Feb 9, 2017

### Dr Max

Hi :)

im wondering if there is a video where a calculated model and the same situation in reality gets compared ? :)
e.g. water drop, or something crashing with a certain speed :)

thanks for any help :)

2. Feb 9, 2017

### Mastermind01

Walter Lewis's legendary mit introductory physics lectures contain a few demonstrations which he compares with the calculated value. I don't remember the exact lecture but in one he showed how the mass didn't affect a pendulum. There are others too like a weighing machine in free fall. While the lectures have been taken down from OCW you can find them on YouTube.

Also: I don't think this is the correct forum topic you've posted under, although I'm not sure what the correct topic is either.

3. Feb 9, 2017

### Staff: Mentor

This is a nice one:

4. Feb 9, 2017

### ZapperZ

Staff Emeritus
Wait... isn't this what is done routinely in college physics experiments?!

Zz.

5. Feb 16, 2017

### Dr Max

First thanks for all replies so far :)

Actually I was looking for calculated water vs real water, something like that. I just want to see how close to reality the best model gets right now. Whats the state of the art ? :)

6. Feb 16, 2017

### ZapperZ

Staff Emeritus
You are aware that in this post, you didn't state anything about what property that you want to measure, aren't you? "calculated water vs real water" is a "huh?"-type of statement. What exactly about the properties of water that you are trying to compare?

It usually saves a lot of time and effort on our part if you, from the get-go, be specific and clear, rather than produce a rather vague question and topic about a generic "calculated model".

Zz.

7. Feb 17, 2017

### Dr Max

Okay Im sry, I werent aware of this problem. I do computer science :)

Basicly im looking for a experimental setup, lets say a bowl of water Diameter 20 cm, the bowl is filled with exactly 200ml of water, 10 cm above the ground there is a pipet attached, the pipet will release a drop of the same volume everytime used. The moment when the drop hits the water is my point of interest.

And now im looking for a video, that films this setup and compares it to the same situation but calculated in a computer visualized. How close does the computer model get ? I guess you would need to calculate all properties at once. As in reality properties are not isolated are they? :)

(it could also be a different setup, im just curious about the quality of todays models)

I hope this specifies :) and we can now understand each other
thank you :)

8. Feb 17, 2017

### ZapperZ

Staff Emeritus
That's no excuse. What if I say "Hey Dr Max, I want you to write a program to be used for water." Would that make any sense to you on what you should do?

I bet not. You'd ask "OK, what do you want the program to actually do?"

That is essentially what you are asking here. But it seems that you are still not being clear, based on this:

Here's the thing: What exactly are you trying to MEASURE? You've described the scenario, but you've never clearly indicated what actually are you interested in measuring? After all, we are talking about something quantitative, aren't we? You wanted to compare with this "physical reality", but yet, you never once stated what quantity we are trying to measure and compare!

This is what has been very puzzling in this entire thread.

Zz.

9. Feb 17, 2017

### rumborak

@ZapperZ , I think you're being a bit harsh here.

While I agree the actual question needs to be made clearer, I highly suspect this is a question about modeling the physical behavior of water, like so many graphics engine do, and what the difference to real water is.

10. Feb 17, 2017

### ZapperZ

Staff Emeritus
No, I don't think I'm being harsh. Modeling WHAT behavior of water? It's temperature? It's viscosity? It's volume? It's dynamics when it goes SPLAT? There isn't a single quantity that has been mentioned here that is of interest. You can't simply say "let's model water". This statement is meaningless. You have to list out the physical quantities that you want to model.

Zz.

11. Feb 18, 2017

### lychette

You seem to be angry !!

12. Mar 7, 2017

### Dr Max

wow, i never thought this would be such a touch thing :)

yes its about modelling. Basicly if you want to model corectly, closest to reality, you need to consider all properties at once dont you ? :)

I want to see a video, visual representation, light that hits my eyes reflected by the drop, dropping and splashing.

13. Mar 7, 2017

### A.T.

I would try a search engine. Or forums related to computer graphics or fluid dynamics software.

14. Mar 7, 2017