Light wands are small tubes that can be used to give off light without electricity or fire.

a light wand keeps two fluids separate from each other until the wand is bent. once the wand is bent, the tube holding the inner fluid breaks, and the two fluids mix together inside the wand

Answerinternal combustion engine fuel;

Year  1936,  lehman predicted that the earths 'inner core' is solid. she observed that the seismic signals during her study were bent and did not pass through instead bouncing back. later it was confirmed that the earth's inner core was solid made up of nickel-iron and had a molten outer core.

The force is push or pull