Even a small cloud can weigh as much as four tonnes – but gravity, chemistry and temperature keep them floating in the sky.
Pollutants can increase stress levels, which in turn affects judgment and makes some people more likely to commit crime.
The students of class 3F at Ferny Grove State School want to know how they get oxygen into the International Space Station.
Australia needs stronger policy aimed at curbing air pollution, but the options currently on the table fall short. For now, we could all aim to drive less and turn off the engine when the car is idle.
There's something in the air that actually has health benefits when you take time to walk among the plants and trees. What that is exactly is still being studied by scientists.