Meteorologist Adam Sherwinski explains how air pressure works to ciLiving host Jaclyn Friedlander using the egg in a bottle experiment. How do wildfires start, and how long do they last?

For the most impressive bubbles, experiment with the volume of ... pressure by tapping the valve or unscrewing the bottle cap, the bottle air pressure - outside the bubbles - goes down.

There are lots of great air pressure demonstrations around, but a leaky water bottle is one of the simplest. It looks impressive and costs almost nothing.

When you breathe in and out, the air pressure inside our lungs changes ... a length of plastic tubing, a big plastic bottle preferably over three litres, a permanent marker pen, then some water.