force of gravity
An object accelerates as it falls towards the ground due to the force of gravity acting on it. The object gains speed because gravity causes a constant acceleration towards the center of the Earth, increasing its velocity as it gets closer to the ground.
Gravitational pull.
what
heat which makes it move faster.
it makes them move faster or vibrate
convection
the smaller they are the less resistance to water and the faster they move.
In warmer water, particles generally have more energy. This makes them move faster, and so spread out faster.
an engine
Last time I check they moved faster on smooth ground
makes the molecules in the water move faster.
It makes the air move faster or quicker