The present study has been made to obtain fundamental knowledge on the mechanism of contact of particles with liquid metal during powder injection. A spherical body was dropped onto a stagnant mercury bath and the behavior of the penetration of the sphere was recorded by a high speed cinecamera. The sphere impinging the liquid surface makes a cavity. Then the sphere jumps up from the surface of the cavity when the kinetic energy of the sphere is low. However, the sphere with high kinetic energy dips into the liquid while the cavity disappears; shortly afterward the sphere rises back to the surface with a mercury film. Based on the measurement of the jumping height of the sphere and the time during which the sphere is immersed in the liquid, the critical condition for the particle penetration into the liquid has been determined. Taking into account the inertia of the liquid surrounding the sphere and the cavity formation, one has given a new model describing the penetrating behavior of the sphere into the liquid. The experimental results are well explained by the theoretical calculation.