Ferrofluid Spikes
Liquid grows sharp black spikes.
Teaching & key ideas
What you do: Move magnet near sealed ferrofluid.
What students see: Liquid grows sharp black spikes.
Why it works: Magnetic nanoparticles align with field while surface tension resists deformation.
Question to ask: How can a liquid make pointy shapes?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: How can a liquid make pointy shapes?