Physics is a natural science concerned with the study of matter and it’s relation to space and time. It looks at concepts related to this like energy and force in order to understand the behaviors of the universe.
In theory, the speed of light, in a perfect vacuum, measured from an inertial frame, is constant with an exact value of 299,792,458 m/s.
There is no limit to the amount of times one can fold a piece of paper in half if the paper is large enough. However, because the thickness of the paper grows exponentially, a lot of paper would be needed to make more than 8 folds.
The bed of nails principle states that while laying on one nail is enough to puncture a person’s skin, laying on many distributed nails isn’t.
All elementary particles exhibit wave-particle duality, acting as both a particle and a wave.