# Dominoes animation shows how a pressure/sound wave is fastest in solids and slowest in gases

Dominoesanimation shows how a pressure/sound wave is fastest in solids and slowest in gases

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1. afrodoom says:

GLORY! I’m teaching waves in a few weeks. Flawless timing.

2. moreawkwardthenyou says:

Awesome demonstration! Density is the key baby.

3. omega_agemo says:

I watched a myth busters video recently where he explains that sound travels faster through helium because it is less dense than air. Thus you get a higher voice.

Why is this the case when sound clearly travels faster through denser mediums?

4. hb-semt says:

Now i want to eat some pizza. like common even the colors match domino’s brand

i needed an emberassingly long time to figure out that the key is the space between the dominoes…

6. twitchedawake says:

I thought it was faster in water due to the incompressibility of it?

7. TheLatvianHamster says:

Gas is barely trying. Smh -_-

8. [deleted] says:

[deleted]

9. Rewotar says:

Slowass gas.

speed = (elastic component/inertial component)^.5

This is true for any mechanical wave. This means that all else equal, the denser the medium the slower the wave. The reason sound travels faster in solids is because their elasticity (bulk modulus) is so much higher.

Also solids can transmit different waves at different speeds because they have multiple elastic modes (shear, compression, torsion, etc.) which have different moduli associated with them.

Dominoes are not a wave. They are not an interplay between a restoring force and inertia. Dominoes are a chain reaction which is an interplay between stored potential energy and activation energy. Therefor, this gif is a vulgar mnemonic at best, but I feel that as an analogy this will likely lead to misconceptions.

11. kawfey says:

/u/mrpennywhistle

12. kcMasterpiece says:

Is…is this apocryphal? Not the idea, but using dominoes to demonstrate it. /u/mrpennywhistle ?

13. [deleted] says:

not a good analogy in my opinion…

14. Erikpendragon says:

/u/mrpennywhistle

15. MedVIP says:

16. practicalguy says:

I’m not a science guy but couldn’t you do this with gravity and light too? And see what the effects would be.

17. Tophurius says:

18. SwampthingsSwampButt says:

Like why wouldn’t you show the waves traveling through various densities of objects?

I know I’ve seen this elsewhere before.

Is this mostly a medical thing?

19. fyrestrtr says:

20. UnspokenOwl says:

So simple!

21. jinks101 says:

Gas is pulling up the rear once again.

22. B-WASH says:

Could you use this to explain the difference between running at different speeds. Each domino being footsteps to show how much more energy is used for sprinting and how long strides are not as fast but use less energy to get the same distance.

23. tRussianPlayer says:

Спасибо !

24. wbeaty says:

TYPICAL MISCONCEPTION, common in grade-school: that liquid density and behavior is half-way between gas and solid.

Instead, liquid and solid are nearly identical. Gas is sparse in comparison. Sound in gas will crawl along like a snail, while sounds in liquid and solid race along nearly equally (solid wins the race of course.)

25. [deleted] says:

[deleted]