Diamonds can generate electricity, the leap second is being scrapped, and you're walking in the footsteps of human ancestors — how up to date is your science knowledge?

Seven fresh science stories — from microplastic coffee cups to a spacetime crystal collapsing into a black hole. Let's see how much stuck!

1. What did researchers at the University of Queensland find about takeaway coffee cups?
2. What surprising property was just discovered in diamond?
3. What is the physicists' debate about order spontaneously emerging from disorder actually about?
4. What does the University of Zurich researchers' underwear method measure?
5. What are international timekeeping regulators scrapping?
6. What do the 1.4-million-year-old footprints found in Kenya suggest?
7. What can happen to a 'spacetime crystal' from a tiny energy change, according to a new physics model?