1. Water can boil and freeze at the same time
Seriously, it's called the 'triple point', and it occurs when the temperature and pressure is just right for the three phases (gas, liquid, and solid) of a substance to coexist in thermodynamic equilibrium. This video shows cyclohexane in a vacuum.
2. Lasers can get trapped in a waterfall
Oh my gosh, yes. Not only is this an incredible example of total internal reflection, it also shows how fibre optic cables work to guide the flow of light.
3. We've got spacecraft hurtling towards the edge of our Solar System really, really fast
We all know rockets are fast, and space is big. But sometimes when we're talking about how long it takes for us to get to distant parts of the Solar System (eight months to get to Mars, are you kidding me?) it can feel like our spacecraft are just crawling along out there.
This gif shows just how wrong that idea is by comparing the speed of the New Horizons probe, which flew past Pluto last year, to a 747 and SR-71 Blackbird.
