See also: ACCIDENT RECONSTRUCTIONS; DEMONSTRATIONS; FLIGHT TESTS
SCIENTIFIC EVIDENCE–Demonstrations and Experiments.

§ 1.  Generally

Experiments conducted either in-court{footnote}  CHECK United States v. Wanoskia, 800 F.2d 235 (10th Cir. 1986) (in-court demonstration).{/footnote} or out-of-court are admissible where they would be helpful in evaluating the evidence, and where a proper foundation is laid for their reliability.{footnote}See 80 ALR2d 488, 514 (flammability experiments); 64 ALR4th 125 (automobile defects).{/footnote}  A trial court’s decision to admit experiment evidence is subject to review for abuse of discretion.{footnote}Sprynczynatyk v. General Motors Corp., 771 F.2d 1112, 1124 (8th Cir. 1985); Four Corners Helicopters, Inc. v. Turbomeca, S.A., 979 F.2d 1434 (10th Cir. 1992).
Brennan v. Wisconsin Cent. Ltd., 591 N.E.2d 494 (Ill. App. Ct. 1992).{/footnote}

§ 2.  Similarity to Actual Events

If the purpose of the experiment is to simulate a real-life occurrence, there must be proof that experimental conditions are substantially similar to those at time of occurrence.{footnote}Williams v. Briggs Co., 62 F.3d 703 (5th Cir. 1995) (test conducted on water heater involved in suit exlcuded due to repairs since time of accident); Barnes v. General Motors Corp., 547 F.2d 275 (5th Cir. 1977); McKnight By and Through Ludwig v. Johnson Controls, Inc., 36 F.3d 1396 (8th Cir. 1994) (testing of same model of car battery as involvded in accident); Four Corners Helicopters, Inc. v. Turbomeca, S.A., 979 F.2d 1434 (10th Cir. 1992); Jackson v. Fletcher, 647 F.2d 1020, 1027 (10th Cir. 1981).
Culpepper v. Volkswagen of America, 33 Cal. App. 3d 510 (1973); Galindo v. Riddell, Inc., 107 Ill. App. 3d 139, 144, 62 Ill. Dec. 849, 437 N.E.2d 376 (__ DIst. 1982); Dunning v. Metropolitan Life Ins. Co., 314 Ill. App. 222, 41 N.E.2d 297 (3d Dist. 1941) (experiment to determine whether gunshot wound could have been self-inflicted).
CHECK Hall v. General MotorsCorp., 647 F.2d 175 (D.C. Cir. 1980 (out-of-court crash test).{/footnote}  There is no such requirement for experiments designed simply to demonstrate general physical principles forming the basis for an expert opinion,{footnote}Hinkle v. City of Clarksburg, 81 F.3d 416 (4th Cir. 1996); Four Corners Helicopters, Inc. v. Turbomeca, S.A., 979 F.2d 1434 (10th Cir. 1992); Bannister v. Town of Noble, 812 F.2d 1265 (10th Cir. 1987) (videotape of car going off ramp).
Brennan v. Wisconsin Cent. Ltd., 591 N.E.2d 494, 169 Ill. Dec. 321 (2d Dist. 1992) (railroad-automobile collision).{/footnote} although it has often been held that the court must give an appropriate limiting instruction.{footnote}Montag v. Honda Motor Co., Ltd., 75 F.3d 1414 (10th Cir. 1996) (automobile accident); Brandt v. French, 638 F.2d 209, 212 (10th Cir. 1981); Zurzolo v. General Motors Corp., 69 F.R.D. 469, 473 (E.D.Pa. 1975).
But see Robinson v. Audi Nsu Auto Union Aktiengesellschaft, 739 F.2d 1481 (10th Cir. 1984) (limiting instruction must be requested or it is waived).{/footnote} This distinction sometimes proves difficult to apply,{footnote}  See, e.g., Robbins v. Whelan, 653 F.2d 47, 49 (1st Cir. 1981) (DOT study of braking distances).  {/footnote} and it has been recognized that since experiments generally fall somewhere on a continuous spectrum from abstract to realistic, there should be a greater degree of similarity required as the experiment becomes less abstract and more realistic.{footnote}McKnight By and Through Ludwig v. Johnson Controls, Inc., 36 F.3d 1396 (8th Cir. 1994) (testing of same model of car battery as involvded in accident).{/footnote}  With experiments designed simply to demonstrate general physical principles, similarities to the actual events in the case can actually be confusing and unfairly prejudicial, leading to exclusion of the evidence.{footnote}Finchum v. Ford Motor Co., 57 F.3d 526 (7th Cir. 1995) (videotape of experiment involving sled tests of car seats properly excluded); Randall v. Warnaco, Inc., 677 F.2d 1226, 1234, 1234 n.7 (8th Cir. 1982) (admission of experimental evidence "very close to a reenactment of the accident . . . could be deemed unduly prejudicial").{/footnote}

Even where the purpose of a test or experiment is to recreate an accident, the experimental conditions need not be identical to the actual events.{footnote}Estate of Carey by Carey v. Hy-Temp Mfg., Inc., 929 F.2d 1229 (7th Cir. 1991) (product liability); McKnight By and Through Ludwig v. Johnson Controls, Inc., 36 F.3d 1396 (8th Cir. 1994) (testing of same model of car battery as involvded in accident); In Jackson v. Fletcher, 647 F.2d 1020, 1027 (10th Cir. 1981) (conditions “may not be identical but they ought to be sufficiently similar so as to provide a fair comparison.")
{/footnote} In general, dissimilarities between experimental and actual conditions go to the weight of the evidence, not its admissibility.{footnote}Bonilla v. Yamaha Motors Corp., 955 F.2d 150 (1st Cir. 1992); Szeliga v. General Motors Corporation, 728 F.2d 566 (1st Cir. 1984); Kehm v. Proctor & Gamble Mfg. Co., 724 F.2d 613 (8th Cir. 1984); Ramseyer v. General Motors Corp., 417 F.2d 859, 864 (8th Cir. 1969). {/footnote}  Those differences may be brought out on cross-examination.{footnote}Estate of Carey by Carey v. Hy-Temp Mfg., Inc., 929 F.2d 1229 (7th Cir. 1991) (product liability).{/footnote}  However, where the dissimilarities are substantial enough to render the experiment more prejudicial than probative, it will be excluded as evidence.{footnote}Ramsey Prods. Corp. v. Morbark Indus., Inc., 823 F.2d 798 (4th Cir. 1987); Gladhill v. General Motors Corp., 743 F.2d 1049 (4th Cir. 1984); Four Corners Helicopters, Inc. v. Turbomeca, S.A., 979 F.2d 1434 (10th Cir. 1992).{/footnote}

Where the experiment is technical or complex, it must be performed by an expert.  The expert must testify as to the nature of the experiment and the reliability of the experimental results.{footnote}State v. Allison, 51 S.W.2d 51 (Mo. 1932).{/footnote}

Films or photographs of an experiment are admissible, both on the above-stated grounds, and as visual summaries of an expert’s opinion.{footnote}  Brandt v. French, 638 F.2d 209, 212 (10th Cir. 1981); Johnson v. Matlock, 771 F.2d 1432 (10th Cir. 1985). {/footnote}  Such evidence must not be merely cumulative, however.{footnote}  Johnson v. William C. Ellis & Sons Iron Works, 604 F.2d 950, 958 (5th Cir. 1979); Finchum v. Ford Motor Co., 57 F.3d 526 (7th Cir. 1995) (videotape of experiment involving sled tests of car seats properly excluded);  Sprynczynatyk v. General Motors Corp., 771 F.2d 1112, 1124 (8th Cir. 1985) (videotapes, pictures and summaries of tests on accident car properly excluded as cumulative of expert testimony).{/footnote}  Nor must it cause confusion or undue delay.

§ 2.  Presence of Criminal Defendant

An experiment is not rendered inadmissible in a criminal case by the absence of the defendant when it was conducted.{footnote}17 A.L.R.2d 1078.{/footnote}  Admission of the experiment is not in violation of the defendant’s right of confrontation.