# Underwater Explosions (Science with Alan Sailer!) - Smarter Every Day 63 | Summary and Q&A

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October 14, 2012
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SmarterEveryDay
Underwater Explosions (Science with Alan Sailer!) - Smarter Every Day 63

## TL;DR

High-speed photographer Alan Sailer and YouTuber Destin from Smarter Every Day study underwater explosions using high-speed photography.

## Key Insights

• 🚄 High-speed photography can capture mesmerizing slow-motion footage of underwater explosions.
• 👋 Understanding the dynamics of an explosion requires considering factors like fluid dynamics, cavitation, and pressure waves.
• 💦 Cavitation occurs when the pressure drops below a threshold, causing the liquid to turn into vapor and form bubbles.
• 🖐️ Fluid momentum plays a crucial role in the collapse of a bottle's side walls after an explosion.

## Transcript

Hey it's me Destin welcome back to Smarter Every Day. So today I'm in California and I have the great privilege of introducing the MAN... Alan Sailer.

• Hello
• Alan Sailer is, if you don't know, one of the best high speed photographers that currently does the art. So I'm here in his garden, back behind his house, and we're going to basically study... Read More

### Q: Why does the bottle get sucked in on the top after the explosion instead of blowing outwards?

The bottle's explosion causes a high-pressure wave that creates a low-pressure spot, leading to cavitation – the formation of bubbles. These bubbles collapse and pull in fluid, causing the bottle to be sucked in on the top.

### Q: What causes bubbles to form in a liquid?

Bubbles in a liquid are caused by cavitation, which occurs when the pressure drops below a certain threshold, turning the liquid into vapor.

### Q: How does fluid momentum affect the explosion's dynamics?

Fluid momentum causes fluid in the bottle to be blown out of the bottom, creating an oscillating pressure that pulls liquid from the top and collapses the bottle's side walls.

### Q: How is super cavitation used in torpedo technology?

Super cavitation involves creating a bubble on the front of a torpedo, reducing drag and allowing for higher speeds underwater.

## Summary & Key Takeaways

• Destin introduces Alan Sailer, a renowned high-speed photographer, and together they study explosions underwater using firecrackers and high-speed photography.

• The duo changes camera settings to capture lower exposure times and higher frame rates, resulting in stunning slow-motion footage of the explosions.

• They try to understand why the explosion causes the bottle to be sucked in on the top instead of blowing out, delving into theories of fluid dynamics and cavitation.