Li explained the law of conserving energy with just one coin
energy is a wonderful thing, exists around our lives, from energy that sustains life for people to energy to generate electricity ... but to answer what energy is, not everyoneProfessor My explains the technique of climbing walls with bamboo pole of Vietnamese task force
using only a long bamboo stick, the vietnamese task force can climb the wall quickly in a direction perpendicular to the wall, which seems impossible.