Buried Alive, Cola Myths, and Hammer Drop

This episode is part of Collection 1, disc 2, episode 1. It is ALSO the fifth episode of Season 2.

NOTE: This episode contains two scary myths (if you have sensitive students, like I do). One is about falling into water and another is about being buried alive. DON’T TRY THESE AT HOME. And one of the cola myths is about sperm.

Myths tested:
Is it possible to survive for days inside a coffin?
Does Cola have special properties?
Will throwing a hammer off a bridge to break the surface tension of the water save a person who jumped off the bridge?

The Science behind Buried Alive
The main ideas here are human respiration and the weight of dirt. The key questions:
• How much does dirt weight? How strong does the coffin need to be?
• How much air does a man need?

Students can explore the materials that coffins are made of (wood, aluminum…), respiration rates at rest/under stress, the volume of a coffin (and the displacement of the man inside the coffin….how much air is there room for?). Related would be a study of burial rituals (I think Japanese are traditionally buried sitting down not lying down).

The Science behind Cola Chemistry
The chemistry and potential uses of cola (and realizing that the familiar may be more than meets the eye) are the main ideas here. The key questions:
• What is cola made of?
• What are acids able to do?
• What conditions are best/worst for sperm?

Students can explore the chemistry of colas. This episode is connected to others about the chemistry of familiar fluids: Pirate Special, Vodka… (MORE HERE). It is also connected to the famous Diet Coke & Mentos episode.

The Science behind Hammer Drop
Gravity of falling, surface tension and viscosity are the main ideas here. The key questions:
• What is surface tension and how does breaking it change the energy of impact with water?
• How viscous is water?

Students can explore the properties of water, and examine the impact of different object profiles as they hit the surface (diving, for example).

Penny Drop/Deadly Microwaves/Radio Fillings

This episode is part of Collection 1, disc 1, episode 3. It is ALSO the fourth episode of Season 2.

NOTE: This episode is one of the richer ones, science curriculum-wise. I recommend it for those new to using Mythbusters in the classroom.

 

Myths tested:
Will a penny dropped from the top of the Empire State Building kill a person ?
Can a person's internal organs be cooked by a tanning booth?
Can tooth fillings receive radio waves?

The Science behind Penny Drop
I use this episode more than any other, because it so beautifully illustrates the idea of gravitational acceleration and terminal velocity. The main ideas here are gravity and terminal velocity. The key questions:
• How fast does something fall?

An object falling toward the surface of the Earth will fall 9.81 meters (or 32.18 feet) per second faster every second (an acceleration of 9.81 m/s² or 32.18 ft/s²).

Near the surface of the Earth, an object in free fall in a vacuum will accelerate at approximately 9.8 m/s², independent of its mass.

With air resistance acting upon an object that has been dropped, the object will eventually reach a terminal velocity, around 56 m/s (200 km/h or 120 mph) for a human body. Terminal velocity depends on many factors including mass, drag coefficient, and relative surface area, and will only be achieved if the fall is from sufficient altitude.

The penny, falling from the top of the Eiffel Tower, reaches a terminal velocity of

• What is terminal velocity?

A free-falling object achieves its terminal velocity when the downward force of gravity (F_g) equals the upward force of drag (F_d). This causes the net force on the object to be zero, resulting in an acceleration of zero. This doesn't mean it stops falling; this means the speed of its fall doesn't continue to increase over the length of the fall. The object doesn't fall faster and faster infinitely. It falls faster and faster UNTIL it stops increasing the speed of its fall. It's still falling, it's just falling at a constant speed.

As the object accelerates (usually downwards due to gravity), the drag force acting on the object increases, causing the acceleration to decrease. At a particular speed, the drag force produced will equal the object's weight (mg). At this point the object ceases to accelerate altogether and continues falling at a constant speed called terminal velocity (also called settling velocity). Terminal velocity varies directly with the ratio of weight to drag. More drag means a lower terminal velocity, while increased weight means a higher terminal velocity. An object moving downward with greater than terminal velocity (for example because it was affected by a downward force or it fell from a thinner part of the atmosphere or it changed shape) will slow until it reaches terminal velocity.

What causes drag? Friction. Bigger surface area = higher drag. Think parachute.

• What does mass have to do with it?

Students can explore the impact of objects dropped or thrown, and the relative impact of objects of varying mass. There is a strong connection between this myth and “Bullet Dropped/Shot” in Knock Your Socks Off, Episode 12, Season 7, and with “Bullets Fired Up” in Season 4, Episode 7.

The Science behind Deadly Microwaves
The mystery of life that is the microwave is the main idea here. The key questions:
• How do microwaves work anyway?
• Why is it not OK to put metal in a microwave?
• Why does water heated in a microwave sometimes “explode” (boil over really quickly)?
• Adam and Jaime choose not to test the dog in the microwave myth. How is this an ethical decision, and what is the role of ethics in science? In TV shows?

Students can explore the electromagnetic spectrum and frequency/wavelength relationship, the anatomy of a microwave, compare foods cooked in a microwave vs. a regular oven, learn about convection ovens, and any of their own ideas about microwaves. This episode is connected to others about microwaves and EMF phenomena: Season 2, Episode 6, MRI Rays and Tattoos; (MORE HERE)

The Science behind Tanning Booth Cooking
Still more mysteries of the EMF spectrum… UV light is the main idea here. The key questions:
• How do tanning booths work anyway?
• What temperature is required to cook chicken?
• Why does skin turn brown when exposed to UV light? Why do tanning booths cause skin cancer?

Students can explore the electromagnetic spectrum and different kinds of UV light, melanin and skin coloring in various human genotypes (my students are boggled by the evolutionary roots of what they call “race”), sunscreens (fun with UV light sensitive beads!), and safe cooking techniques for chicken.

The Science behind Radio Tooth Fillings
The properties of dental fillings and radio station signals are the main ideas here. The key questions:
• What are dental fillings made of?
• What materials are able to act as receivers for radio signals?

Students can explore how radios work (cheap crystal radio kits are available), and can learn about dental fillings (do old fillings contain mercury?).