Slow Motion of an AK-47 Underwater (Part 1) - Smarter Every Day 95 | Summary and Q&A

TL;DR

Destin uses a high-speed camera to examine the impact of water on the operation of guns, showcasing how water affects the bolt movement and chamber pressure.

Key Insights

• 💦 Water increases the bolt movement speed due to the need to accelerate the mass of water in front of the bullet.
• 🔫 The incompressibility of water allows pressure information to reach the piston faster, resulting in higher chamber pressure when shooting underwater.
• 😎 Using tempered glass instead of plate glass can lead to experiment failure.
• 🫢 The AK-47's piston mechanism operates by harnessing the gas pressure from a fired bullet.
• 🚄 High-speed cameras are valuable tools for studying scientific phenomena.
• 🦾 Understanding the principles behind gun mechanics can provide insights into the behavior of firearms in different environments.
• 🌱 Experiments should be carefully planned and executed to avoid mistakes and ensure accurate results.

Transcript

Hey it's me Destin. This week on Smarter Every Day I'm gonna trick you into learning science using a gun and a high speed camera. You remember the old pistols underwater video? Well this week I'm gonna do it with a better high speed camera, and a bigger gun. [music] [power tools] OK here's the setup. This is my dad's AK-47. First things first. The ... Read More

Questions & Answers

Q: How does the AK-47's piston mechanism work?

The gas from the fired bullet flows into a cylinder, pushing down the piston. The piston then moves the bolt, chambering the next round from the magazine.

Q: What happens to the water when the gas flows into the cylinder?

The water slows down the bolt movement due to the need to accelerate the mass of water in front of the bullet. However, in this experiment, water actually speeds up the bolt movement.

Q: Why does the gunshot in water show higher chamber pressure?

Water is incompressible, meaning pressure information reaches the piston faster. This leads to higher chamber pressure when shooting underwater.

Q: What is the difference in the experiment using tempered glass instead of plate glass?

Tempered glass shatters entirely when the edge is broken, unlike plate glass. This led to the experiment's failure and Destin's apology.

Summary & Key Takeaways

• Destin sets up an AK-47 with a metal contraption to capture the bolt movement in high-speed footage.

• He compares the bolt movement in the air and underwater, hypothesizing that water will slow down the bolt.

• The experiment shows that water actually speeds up the bolt movement due to the need to accelerate the mass of water and the incompressibility of water compared to air.