Survival in a Sealed Car
How long would you survive sealed in a compact car?& Is there enough oxygen to survive your journey, or should you just open a window to avoid suffocating on your own expelled gas?& Also, we ask if lightning should interrupt your television viewing - should you unplug your TV in a storm?& And we make an oil enquiry - how do we know that we'll run out of oil? How do we know we won't find more?
In this episode
00:00 - Surviving in a Sealed Car?
Surviving in a Sealed Car?
Dr Gisli Jenkins, University of Nottingham:The easy answer to this question is that you will never run out of air. You will just exchange the breath that you breathe in with the breath that you breathe out. I guess what the question alludes to is how long you have to survive in that box before you die. What you are doing is you're exchanging ambient air with exhaled air and the gaseous composition of the two airs is quite different. Ambient air has a CO2 concentration of about 0.5% and oxygen concentration of about 21%. Exhaled air has a CO2 concentration of about 5% and an oxygen concentration of about 13% so what you'll do over time is you'll reduce the oxygen level. The problem is not so much the reduction of oxygen but the increase in carbon dioxide. By the time that the carbon dioxide levels in the air that you breathe reach 15% you'll effectively die. Assuming the box is about 4 cubic metres it would take about 16 hours or so. But you would actually start to feel ill and probably die a lot sooner than that. Actually it could be down to, sort of, five hours.