1. The Belousov-Zhabotinsky Oscillating Reaction

This complex reaction occurs as bromine in an acidic solution is converted into bromide ions then back again. Several research papers have tried to explain the exact process for how this works and it is thought to involve around 18 individual steps.

source: Tim Kench

 

2. Flux Pinning

When a superconductor (a unique type of material that has zero electrical resistance at very cold temperatures) is exposed to a magnetic field, it not only hovers, but can become "quantum locked" at a fixed distance above the magnet. 

source: Association of Science-Technology Centers

 

3. Acoustic Water Spout

Placed against a speaker playing a 24hz sine wave, a stream of water will vibrate and produce this hypnotizing pattern. Of course, you usually can't see it unless viewed through a camera set to 24 fps. 

source: brusspup

 

4. Explosive Polymerization

Sulphuric acid reacts with Nitroaniline, generating a lot of heat, carbon, and gasses. The resulting explosion of byproducts rapidly cools in the air and solidifies in process similar to how popcorn gets its fluffy shape.
 

source: Plasticraincoat1

 

5. A Slinky Doesn't "Know" It's Been Dropped

People tend to forget that a slinky is technically a spring. Even when it's dropped, the bottom is still being pulled towards the spring's center of mass. It isn't until the center of mass reaches the bottom that the entire slinky hits the ground. But for a second there, it's confusing as the laws of physics sorts itself out.
 
source: Adam Shomsky
 
 

6. Lighting a Fire With Air

An easy to use firestarter ignites flammable materials with pressure instead of a spark. The rapidly compressed air creates heat (physics 101), enough to set combustible materials ablaze. This might not be extraordinary to some, after all it's basically how diesel engines work.
 
source: QuestaconNSTC

 

7. The Briggs-Rauscher Reaction

This is a popular example of a "chemical clock". In this instance, a series of reactions both creates iodine (causing it to react with starch in the mixture to form that black-blue color) and then consumes iodine (making the solution clear again). The reaction oscillates back and forth around 10 times. 
 
 
 

8. Supercooled Water

Everybody knows that water freezes at 0 degrees Celsius, but it doesn't necessarily HAVE to. If the water is free of impurities, there won't be any nucleation points for the ice crystals to start growing, and the liquid water can get even colder. Once the supercooled water is disturbed, the crystals form quickly, almost snapping into place. That's how that tower of slush rises from a bottle of seemingly normal water.
 
 
 

9. Lenz's Law.

Even though copper does not have a strong magnetic field on its own (magnets won't stick to it), when a powerful magnet is dropped down a copper tube something interesting happens. As it falls a small electric current is generated, this produces an electromagnetic field that acts against the magnet and slows its descent, momentarily making gravity look like a real goober.
 
source: igor30
 
 

10. The Magnus Effect

Adding even a slight bit of spin to a ball or cylinder will curve its airborne trajectory drastically. This effect is utilized in pretty much every sport from soccer to baseball to ping pong. Despite the protestations of X-Men fans, it has nothing to do with Magneto.

source: Veritasium