The introduction of an object submitted as being similar to the one used in an incident is admissible as demonstrative evidence to aid the jury in understanding the oral testimony educed at trial. Witness qualified to establish the theory's validity and the instrument's reliability. The underlying theory is generally accepted as valid and the instrument is generally accepted as reliable. Instrument was in good working condition and was used by witness qualified to conduct and interpret the test results. Witness used the proper procedures.
Witness states the test results.
If the theory and instrument are very generally accepted, the judge will judicially notice those elements of the foundation upon a proper timely request by counsel.