How to build a Cloud Chamber

Summary

This script describes a DIY project to create a particle detector, allowing viewers to observe cosmic rays. Using a plastic tub, felt, a lid, isopropyl alcohol, and dry ice, the setup forms a cloud chamber. When cosmic particles pass through, they ionize the alcohol vapor, creating visible tracks. The script explains how different particles leave distinct patterns, with alpha particles appearing as thick tracks and muons as long, straight lines, while electrons and positrons produce wavy paths. It's a simple yet fascinating way to explore fundamental particles.

Takeaways

• 🌌 Every second, around 10,000 cosmic ray particles pass through you, but they are invisible and intangible.
• 🔍 To detect these particles, you can build a DIY cloud chamber using a clear plastic container, like a fish tank.
• 🧤 Safety is crucial when handling materials like isopropyl alcohol and dry ice; use gloves and goggles.
• 🧪 Isopropyl alcohol, when dampened and placed over dry ice, creates a super-cooled environment inside the chamber.
• 🌡 The alcohol evaporates and cools as it descends, ready to condense into droplets at the slightest disturbance.
• 🌀 Cosmic rays ionize gas molecules in the chamber, causing alcohol vapor to condense around the ionized path, visible as tracks.
• 💡 The cloud chamber allows you to visually observe the paths of different types of subatomic particles from space.
• 🔦 In a dark room, using a flashlight, the tracks of particles can be seen more clearly, with varying appearances based on the particle type.
• 📏 Alpha particles from radon atoms leave large, fat tracks, while muons create very long, straight paths.
• ➰ Electrons and positrons produce smaller, more erratic tracks due to their lighter mass and frequent interactions with other particles.

Q & A

What are the particles that constantly bombard us from space called?

The particles that constantly bombard us from space are called cosmic rays.

What materials are needed to make a simple particle detector according to the script?

To make a simple particle detector, you need a clear plastic tub, felt, a lid or base for the tub, isopropyl alcohol, and dry ice.

Why is it recommended to use a black lid for the particle detector?

A black lid is preferable because it helps in better visibility of the particle tracks when observing the detector in a dark environment.

Why is it important to wear safety goggles and gloves when working with isopropyl alcohol and dry ice?

Isopropyl alcohol can cause irritation if it comes into contact with eyes, and dry ice is extremely cold, so safety goggles and gloves are necessary to prevent injury.

How does the dry ice contribute to the functioning of the particle detector?

The dry ice cools the bottom of the detector, creating a temperature gradient that causes the alcohol to evaporate and then condense, forming a visible cloud where particle tracks can be seen.

What happens to the isopropyl alcohol inside the fish tank during the particle detection process?

The isopropyl alcohol inside the fish tank evaporates due to the room temperature and then condenses into a visible cloud when it cools down near the bottom where the dry ice is.

How do cosmic rays create tracks in the cloud chamber?

Cosmic rays create tracks in the cloud chamber by ionizing gas molecules, causing the evaporated alcohol molecules to clump together and form tiny droplets along the ionized path.

What do the different types of particle tracks look like in the cloud chamber?

The tracks vary in appearance: large, fat tracks are from alpha particles, long straight ones are from muons, and smaller, curvy tracks are from electrons and positrons.

Why are muons referred to as the 'bowling balls of fundamental particles'?

Muons are referred to as the 'bowling balls of fundamental particles' because they are较重 and pass through the air in a straight line without much deflection.

How can you best observe the particle tracks in the cloud chamber?

The particle tracks can be best observed by turning off the lights and using a flashlight, which will illuminate the droplets formed along the paths of the particles.