He is using the filtration method.
It’s a technique which is used for separation of solids and fluids by putting them through a medium which allows only fluid to pass through, leaving the solids (in this case the soil) alone.
The fluid that passed is called the filtrate.
speed and direction in which an object is moving. both speed and direction of motion. is a vector. two or more velocities add by velocity addition.
Helium gas would be the one to effuse faster as compared to krypton. This is because krypton is heavier than helium. Heavier molecules would require more energy to move so they tend to effuse slower than molecules that are lighter which will only require less energy.
