The experiment used water (H2O), methane (CH4), ammonia (NH3) and hydrogen (H2). The chemicals were all sealed inside a sterile array of glass tubes and flasks connected together in a loop, with one flask half-full of liquid water and another flask containing a pair of electrodes. The liquid water was heated to induce evaporation, sparks were fired between the electrodes to simulate lightning through the atmosphere and water vapor, and then the atmosphere was cooled again so that the water could condense and trickle back into the first flask in a continuous cycle.
In his interview with Lee Strobel, when discussing the famous Miller-Urey experiment, Jonathan wells said,
"Now, it's true that a good organic chemist can turn formaldehyde and cyanide into biological molecules. But to suggest that formaldehyde and cyanide give you the right substrate for the origin of life, Well, it's just a joke."
He let the point sink in before delivering the clincher. "Do you know what you get?" he asked. "Embalming fluid!"