How does a lie detector work, and what causes car sickness?

We explore the curious questions that science can answer

If you were strapped to a polygraph machine – would you feel nervous? (Getty/iStock)

How does a lie detector work?

Lie detectors work on the principle that anyone who’s lying will be nervous, and nervous people tend to produce more adrenaline, which makes their hearts beat faster, their skin temperature rise and makes them sweat more. A lie detector basically measures how these things change during questioning. However, people generally get nervous anyway if they’re being questioned, while some people can control their heart rate if they concentrate. So, lie detectors aren’t foolproof indicators of guilt.

Some microwave food containers seem to have metallic films on top of them. Isn't that dangerous, because metal things in microwaves cause sparks?