The MythBusters The MythBusters

MythBusters Episode 173: Walk a Straight Line

Premier Date: October 12, 2011

It is impossible for a blindfolded person to travel in a straight line.


Adam and Jamie decided to test the myth by walking, swimming, and driving. They wore blackout goggles and noise-blocking headphones or earplugs, and used portable GPS devices to track their movements. The walking test, set in an open field, required each man to try to walk toward a target 3,000 ft (914 m) away; both ended up far off course and/or at the edge of the field. They then tried to swim directly across a lake and drive a golf cart straight down an abandoned airfield runway, also without success, and declared the myth confirmed.

For a real-world situation, they then decided to investigate the ability of a person to navigate a straight course if lost in the woods. With no landmarks or destination in view, they tried to follow separate headings for 30 minutes and succeeded by using the Sun’s position to stay on track. However, with buckets on their heads to simulate reduced visibility at night or in a snowstorm, Adam did poorly while Jamie stayed on track by carefully pacing around obstacles, drawing on his wilderness survival experience. Finally, they attached themselves to opposite ends of a long ladder with hip belts, thinking that each could feel the other’s veering and correct it, but failed the open-field walking test again.

A load of mixed binary explosive (tannerite) in a car trunk can detonate if the car is rear-ended.


At the bomb range, the Build Team set up jars of the two unmixed components, as well as an 8 oz (227 g) jar of the mixed tannerite. Tory fired at them with a high-powered sniper rifle; only the mixed jar exploded when hit. Doubling the sample size gave a larger blast, and shooting one jar in a stack of five created a chain reaction that set them all off. To simulate a freeway rear-end collision, the team half-buried a target car with its nose down and the protruding trunk packed with 50 lb (23 kg) of mixed tannerite. They dropped a second car on it from 150 ft (46 m), nose down, but the load did not explode on impact.

Declaring the myth busted at this point, the team traveled to the New Mexico Institute of Mining and Technology to use the on-site rocket sled apparatus. After setting off a 100 lb (45 kg) load of explosive to determine the appearance of the actual blast, they set a target car on the track, with the same size load, and fitted a pickup truck’s front end onto the sled. Enough rocket motors were attached to accelerate the sled to a top speed of 300 mph (483 km/h), but the impact only disintegrated the target car without triggering a detonation. A cloud of undetonated tannerite was visible sprayed in all directions by the force of the impact.

The tests suggested that tannerite is difficult to detonate unintentionally. Other binary explosives, however, are not necessarily as safe.