Why Is Liquid Oxygen Magnetic When Poured?

TL;DR

Liquid oxygen is magnetic due to its paramagnetic properties, allowing it to hang in a magnetic field created by electromagnets. This phenomenon showcases the Leidenfrost effect, where the liquid hovers instead of falling, unlike most other liquids that don't react visibly to magnetic fields. Additionally, liquid oxygen's magnetic alignment is temporary and disappears when the external field is removed.

Transcript

DIANNA COWERNE (VOICEOVER): This episode is supported by 23andMe. DIANNA COWERNE: I'm so excited. I didn't think there was going to be an opportunity for, like-- you get to handle liquid oxygen. [LAUGHTER] JOSH WOLFE: Oh, yeah. DIANNA COWERN: Throw the switch down. Pour the liquid oxygen. OK. JOSH WOLFE: And then, lift the switch. DIANNA COWERN: ... Read More

Key Insights

• 🫗 Pouring liquid oxygen over a magnetic field results in a captivating demonstration of the Leidenfrost effect and paramagnetism.
• 🤘 Electromagnets create a strong magnetic field between two magnetized metal pieces, enabling the liquid oxygen to hang in the gap.
• 🫗 Liquid oxygen exhibits paramagnetism due to the alignment of its electron's magnetic moments with the external magnetic field.
• 👻 The Leidenfrost effect, not surface tension, allows the liquid oxygen to stick to the metal.
• 💦 Water and most liquids do not visibly react to magnetic fields.
• 😚 Iron loses its magnetism when heated past the Curie point, where the magnetic moments are too energetically disordered to align.
• 😥 The Curie point of iron is around 1043 Kelvin.

Questions & Answers

Q: What enables the liquid oxygen to hang in the magnetic field?

The liquid oxygen exhibits paramagnetism, causing the magnetic moments of its atoms' electrons to align with the external magnetic field.

Q: Why doesn't water or other liquids exhibit the same behavior in a magnetic field?

Unlike liquid oxygen, which possesses paramagnetic properties, water and most other liquids do not visibly react to magnetic fields.

Q: What is the Leidenfrost effect?

The Leidenfrost effect explains how liquid oxygen defies surface tension and clings to the metal due to the different responses of materials to external magnetic fields.

Q: What happens to the magnetism of iron when it is heated?

When heated past the Curie point, the random motion of the magnetic moments in iron prevents them from aligning with an external magnetic field, causing the iron to lose its magnetic properties.

Summary & Key Takeaways

• Dianna Cowern visits MIT to pour liquid oxygen over a magnetic field, creating a captivating demonstration.

• A strong magnetic field is produced between two magnetized metal pieces using electromagnets.

• The liquid oxygen defies gravity and hangs in the magnetic field due to its paramagnetic properties.