The MythBusters The MythBusters

MythBusters Episode 212: DO Try This at Home?

Premier Date: February 1, 2014

This episode involved several myths that viewers might be able to try at home.

Water that has been boiled in a microwave oven will kill plants.

busted, do try at home

Adam built a tray to hold four pairs of romaine lettuce plants, each receiving a different type of water: microwave-boiled, stove-boiled, unheated from the tap, and no water at all. The two boiled samples were cooled to room temperature before being used. All plants received the same amounts of water and light for one week. At the end of this time, Adam found that the plants given microwave-boiled water had grown larger than all the others, and that the ones given no water had died.

The wake from a sharply turning jet boat can put out a fire on a stationary boat. (Based on a viral video.)

confirmed, don’t try at home

The Build Team borrowed a jet boat, and Tory practiced getting it up to speed and doing a sharp 180-degree turn. They loaded a wooden pallet of hay onto a second boat and set it on fire. With Grant and the boat’s owner on board, Tory drove toward the burning boat at 50 miles per hour (80 km/h) and cut a sharp turn, covering the burning boat with a substantial spray of water. The first pass put out the flames, but smoke was still billowing from the hay. Two more passes were made to positively extinguish the fire.

A large number of metronomes placed on a sliding platform will perfectly synchronize.

busted, do try at home

Adam demonstrated that a single metronome on a sliding platform would slightly shake the platform back and forth. He set a lightweight platform on top of two lengths of pipe to act as rollers, and was able to get 2, 5, and 11 metronomes to synchronize. He and Jamie then set up 216 metronomes on foam board which was floating on an air hockey table. During 30 minutes of ticking, only smaller groups of the metronomes fell into and out of sync. Adam commented that variations in manufacturing tolerances would make it nearly impossible to synchronize such a large number of metronomes.

Chrome ball-chain can appear to levitate briefly as it falls out of a container.

confirmed, do try at home

Jamie placed a beaker filled with one long piece of chain on a counter and pulled one end sharply up over the edge to start it falling. High-speed camera footage revealed that the balls did follow the arc of that initial pull, and tests with larger balls and from greater heights increased the effect. He explained that the effect may have been due to the combination of inertia from the pull, the chain’s own weight, and the low friction due to the slick surfaces.

Demonstrations of the classroom science experiment known as “elephant toothpaste.”

only try first version at home

Kari mixed household hydrogen peroxide solution, liquid dish soap, and food coloring in a graduated cylinder, then added a small amount of yeast. The peroxide decomposed into water and oxygen gas, causing the soap to foam up and out of the container.

Kari repeated the experiment, using a concentrated laboratory-grade peroxide solution and potassium iodide instead of yeast. This test generated a large volume of hot foam and steam, and was deemed unsafe for the home. In a final test, described as “Monster Toothpaste”, the Build Team scaled up the recipe by a factor of 200. When the chemicals were mixed, they generated a massive eruption of foam.

Demonstration of a chemical reaction with results resembling a black snake firework, but occurring much more quickly.

don’t try at home

Grant first mixed sugar and sulfuric acid. The sugar decomposed to form steam and carbon residue, but the reaction did not appear to be particularly fast or violent. When he switched the sugar for an unnamed organic compound and heated the mixture for several seconds, it generated an instantaneous burst of smoke and a tall column of carbon. He stressed that the use of sulfuric acid made this reaction dangerous.

Investigating the dangers involved in using a dry ice bomb.

don’t try at home

Adam set up a rig to screw caps onto bottles using a power drill. At the bomb range, he placed a bottle in a frame and added dry ice and water, with pressure sensors arranged around it, then retreated to a safe distance and triggered the drill to put on the cap. The explosion of a 350-ml (12 fl oz) bottle registered a maximum pressure of 3 pounds per square inch (21 kPa); however, Adam and Jamie discovered that one of the frame’s steel supports had fractured and bent.

A 2-liter bottle bulged out greatly before exploding and gave a maximum of 7 pounds per square inch (48 kPa), enough to cause permanent hearing damage. When Adam and Jamie repeated the test with the bottle held in a set of rubber and bone forearms made by Jamie, the blast inflicted several lacerations, fractures, and wounds from embedded shrapnel.

Water falling in front of a stereo speaker can appear to freeze in place.

confirmed, do try at home

Tory set up a pipe to dribble water in front of a speaker and filmed the setup with a video camera, adjusting the output frequency to affect the vibration of the water in midair. Near 24 Hertz, the water seemed to fall very slowly; Tory pointed out that the effect was an optical illusion, caused by the vibration being nearly synchronized with the camera’s filming rate of 24 frames per second. At frequencies below 24 Hertz, the effect made the water appear to rise back toward the pipe.