Today marks one of the biggest shake-ups in the history of measurement. But the new standards on how we define units of mass, length, time and so on are not easy to explain.
It would be difficult, but we could probably build a tower over 2,000 metres tall, which would be like ten normal skyscrapers on top of each other! This is probably not a very good idea though.
Trump's new executive order reflects a fear of sabotage, where an enemy such as China or Russia could turn off critical infrastructure like the internet or communications capability.
In several Australian prisons, babies and toddlers live with their mothers who are serving time. Keeping young children with their mums is a good thing, but they need to be better supported.
UNSW sustainability scientists have run their rulers over the major parties' climate policies to determine whether taking action against climate change is more expensive than doing nothing.
