Small objects flying through space that might collide with another object is called space debris. Space debris is basically a collection of spent objects that are left in space.
this is called law of conservation of momentum
Objects that let all light through are called transparent objects, like glass windows. Objects that only let some light through are called translucent, like a lamp shade, or a curtain. Objects that don't let any light through are called opaque, like a desk.
Sound is a pressure wave. Objects that "allow" sound to travel through them could be called wave guides.
The type of heat transfer by direct contact is called conduction. Heat is transferred through a solid material or between two objects in direct contact with each other. This occurs as the particles in the material or objects collide and transfer energy to each other.
It is called conduction.
Its called Fluid Friction
There are many materials that light can not travel through which are called opaque objects.
Objects that do not absorb LIGHT are called opaque. You can't see through these types of objects.
Why can't light pass through what? To first contributer, don't say that. Say light cannot pass through solid, opaque objects at times.
an earthquake
heat moves from hot to cold, until both objects have the same temperature which is called conduction
It is commonly called gravitation.