Method and apparatus for sonication in connection with preparing a cellular sample containing DNA or RNA for performance of polymerase chain reaction (PCR) or for other reasons where it is important to break down the cell walls and other cellular structures to release cellular contents including DNA. The same methods and apparatus may be used to release DNA or RNA from virus for PCR or other uses. A novel apparatus which is capable of releasing cellular contents or releasing the DNA or RNA of virus without the aid of beads or chemicals is described herein. The apparatus is designed to deliver high levels of sonic energy through optimizing the geometry the apparatus and optimizing the force created by a piezoelectric transducer. The apparatus is capable of processing samples which are contained within fluid in a short amount of time between 30 seconds and two and one half minutes. The apparatus is small and can be field deployable or used in a standard molecular biology laboratory.