How Do Polarized Sunglasses Work?

TL;DR

Polarized lenses block horizontally polarized light to reduce glare and improve visibility.

Transcript

♪ If you’ve been watching SciShow for a while, and you’re super dedicated – and I appreciate that if you are – the title of this video might look a little familiar. That’s because a few years ago, we made a video on polarized lenses and how they reduce glare. But thanks to some comments from viewers, we recently realized that we mixed some things u... Read More

Key Insights

• 🚥 Light waves have different polarizations such as vertical and horizontal.
• 🙂 Polarized sunglasses block horizontally polarized light to reduce glare.
• 🎮 Incorrect explanations in a previous video about polarized lenses are corrected.
• ❓ Sunlight starts unpolarized and can be polarized in different directions upon reflection.
• 🙂 Polarized lenses have long molecules that selectively absorb horizontally polarized light.
• 🙂 Turning polarized lenses on their side allows horizontally polarized light to pass through.
• 😚 Polarized lenses are most effective when sunlight is close to a critical angle for polarization.

Questions & Answers

Q: How do transverse waves affect the polarization of light?

Transverse waves cause light to have different polarizations such as vertical and horizontal, affecting how it oscillates as it moves forward through space.

Q: Why do polarized sunglasses reduce glare from horizontal surfaces?

Polarized sunglasses have long, thin molecules aligned in horizontal rows that absorb horizontally polarized light, blocking glare that is mostly horizontally polarized.

Q: What happens when polarized lenses are turned on their side?

Turning polarized lenses on their side changes the alignment of the long molecules, allowing horizontally polarized light to pass through and causing glare to return.

Q: When do polarized lenses work best in reducing glare?

Polarized lenses work best when sunlight is close to a critical angle where most of its reflected light is horizontally polarized, making them effective in reducing glare early and late in the day.

Summary & Key Takeaways

• Light travels as transverse waves with different polarizations.

• Polarized sunglasses block horizontally polarized light to reduce glare from horizontal surfaces.

• Incorrect explanations in a previous video are corrected regarding how polarized lenses work.