How Does an Etch A Sketch Work?

iStock/Garrett Aitken
iStock/Garrett Aitken

We learned on February 2, 2013, that Etch A Sketch inventor André Cassagnes died last month in France. Here's a look back at his legendary toy.

In 1955, a French electrician named André Cassagnes got an idea for a new toy after seeing how an electrostatic charge could hold aluminum powder to glass. He worked up a prototype for the toy—based on the design of a television screen—in his basement workshop and called it “L'Ecran Magique,” or “the magic screen.” Its joystick, glass and aluminum powder allowed users to draw and erase images and letters with no ink and no mess. Cassagnes sought a patent, put couldn’t pull the money together to get one, so he borrowed from an investor, who sent an employee to pay the fee at the patent office. (The assistant’s name ended up on the patent, and he has often been wrongly credited with the invention of the toy in the decades since.)

Cassagnes’ investor, Paul Chaze, took the toy to several European toy fairs, but it drew little interest. Executives from the Ohio Art Company saw it at the 1959 International Toy Fair in Nuremburg, Germany, and didn’t think much of it at first, either. But they decided to take a chance on the product. [Image credit: The Invisible Agent]

Ohio Art paid $25,000 for the rights to the toy and had their chief engineer, Jerry Burger, collaborate with Cassagnes to perfect it. The company launched the toy in the United States under the name “Etch A Sketch” the following year, just in time for the holiday shopping season.

The Magic Beneath the Screen

When Ohio Art Co. executive William Casley Killgallon brought the toy back from Germany, his 21-year-old son Bill was mesmerized by it. “I was just fascinated,” he told the Toledo Blade in 2010. “I thought, 'How the heck is this working?' I was turning the knobs and just couldn't figure it out.”

And that’s part of the fun, isn’t it? Not knowing how it works? The idea – in a young, fertile imagination – that it might actually be magic? If you prefer to think of it that way, I can’t blame you, but you should stop reading, because here’s what’s going on under the screen:

When you turn the Etch A Sketch upside down and shake it, the inside surface of the screen gets coated with aluminum powder, which will stick to almost anything (mixed in with the powder are small polystyrene beads, which help it flow evenly and keep it from caking).

Also inside are horizontal and vertical bars connected by thin steel wires to the knobs on the face of the toy. A stylus is mounted where the two bars cross, so when you turn a knob, it moves its bar and the bar moves the stylus. As the stylus moves across the inside surface of the screen, it scrapes off the aluminum powder and creates a dark line on the light gray screen, which is just the darkness of the toy’s interior set against the lighter aluminum powder.

To erase their picture, an artist only needs to flip the toy and shake, redistributing the powder over the screen.

Etch A Sketch of Mass Destruction?

In the first season finale of the AMC series Breaking Bad, the protagonist Walter White makes some thermite using the aluminum powder from inside several Etch A Sketches and uses it to melt the lock off of a door he needs to get open. Would that actually work outside of an Emmy-winning TV series?

I’m no Jamie Hyneman, and my girlfriend won’t let me play with explosives in the house (this is, I suppose, her only flaw), so I can’t test this out myself, but it seems pretty straightforward and plausible.

Thermite is made from a metal powder and a metal oxide and produces an exothermic oxidation-reduction reaction, known as a thermite reaction, when heat is applied. This reaction creates extremely high temperatures around a small area and is used for welding in situations where there isn’t enough space for conventional welding equipment (some MIT students also once used it to weld a trolley to its tracks as a prank).

Fuels commonly used in thermite include powdered aluminum, magnesium, calcium and boron. Common oxidizers are boron(III) oxide, silicon(IV) oxide, manganese(IV) oxide and  iron(III) oxide.

Empty a few Etch a Sketchs and you’ve got a small amount of aluminum powder, so all Walter would need is a metal oxide. Iron(III) oxide is easy enough to get (it’s used as a pigment and as “jeweler's rouge”), and an aluminum-iron(III) oxide thermite would easily reach 4500+ degrees (Fahrenheit), enough to melt a steel padlock.

7 Top-Rated Portable Air Conditioners You Can Buy Right Now

Black + Decker/Amazon
Black + Decker/Amazon

The warmest months of the year are just around the corner (in the Northern Hemisphere, anyway), and things are about to get hot. To make indoor life feel a little more bearable, we’ve rounded up a list of some of the top-rated portable air conditioners you can buy online right now.

1. SereneLife 3-in-1 Portable Air Conditioner; $290

SereneLife air conditioner on Amazon.
SereneLife/Amazon

This device—currently the best-selling portable air conditioner on Amazon—is multifunctional, cooling the air while also working as a dehumidifier. Reviewers on Amazon praised this model for how easy it is to set up, but cautioned that it's not meant for large spaces. According to the manufacturer, it's designed to cool down rooms up to 225 square feet, and the most positive reviews came from people using it in their bedroom.

Buy it: Amazon

2. Black + Decker 14,000 BTU Portable Air Conditioner and Heater; $417

Black + Decker portable air conditioner
Black+Decker/Amazon

Black + Decker estimates that this combination portable air conditioner and heater can accommodate rooms up to 350 square feet, and it even comes with a convenient timer so you never have to worry about forgetting to turn it off before you leave the house. The setup is easy—the attached exhaust hose fits into most standard windows, and everything you need for installation is included. This model sits around four stars on Amazon, and it was also picked by Wirecutter as one of the best values on the market.

Buy it: Amazon

3. Mikikin Portable Air Conditioner Fan; $45

Desk air conditioner on Amazon
Mikikin/Amazon

This miniature portable conditioner, which is Amazon's top-selling new portable air conditioner release, is perfect to put on a desk or end table as you work or watch TV during those sweltering dog days. It's currently at a four-star rating on Amazon, and reviewers recommend filling the water tank with a combination of cool water and ice cubes for the best experience.

Buy it: Amazon

4. Juscool Portable Air Conditioner Fan; $56

Juscool portable air conditioner.
Juscool/Amazon

This tiny air conditioner fan, which touts a 4.6-star rating, is unique because it plugs in with a USB cable, so you can hook it up to a laptop or a wall outlet converter to try out any of its three fan speeds. This won't chill a living room, but it does fit on a nightstand or desk to help cool you down in stuffy rooms or makeshift home offices that weren't designed with summer in mind.

Buy it: Amazon

5. SHINCO 8000 BTU Portable Air Conditioner; $320

Shinco portable air conditioner
SHINCO/Amazon

This four-star-rated portable air conditioner is meant for rooms of up to 200 square feet, so think of it for a home office or bedroom. It has two fan speeds, and the included air filter can be rinsed out quickly underneath a faucet. There's also a remote control that lets you adjust the temperature from across the room. This is another one where you'll need a window nearby, but the installation kit and instructions are all included so you won't have to sweat too much over setting it up.

Buy it: Amazon

6. Honeywell MN Series Portable Air Conditioner and Dehumidifier; $400

Honeywell air conditioner on Walmart.
Honeywell/Walmart

Like the other units on this list, Honeywell's portable air conditioner also acts as a dehumidifier or a standard fan when you just want some air to circulate. You can cool a 350-square-foot room with this four-star model, and there are four wheels at the bottom that make moving it from place to place even easier. This one is available on Amazon, too, but Walmart has the lowest price right now.

Buy it: Walmart

7. LG 14,000 BTU Portable Air Conditioner; $699

LG Portable Air Conditioner.
LG/Home Depot

This one won't come cheap, but it packs the acclaim to back it up. It topped Wirecutter's list of best portable air conditioners and currently has a 4.5-star rating on Home Depot's website, with many of the reviews praising how quiet it is while it's running. It's one of the only models you'll find compatible with Alexa and Google Assistant, and it can cool rooms up to 500 square feet. There's also the built-in timer, so you can program it to go on and off whenever you want.

Buy it: Home Depot

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Why Does Altitude Affect Baking?

This woman is going to make a quick stop at Whole Foods' bakery section before book club.
This woman is going to make a quick stop at Whole Foods' bakery section before book club.
nicoletaionescu/iStock via Getty Images

Even if you’re highly skilled in the kitchen, you might find yourself with a deflated cake or bone-dry brownies if you happen to be baking in Aspen, Colorado, for the first time. But why exactly does an oven at high altitude so often wreak havoc on whatever baked good is in it?

According to HuffPost, it all comes down to air pressure. The higher you are above sea level, the lower the air pressure is. This is mostly because there’s less air pressing down on that air from above, and it’s also farther from the gravitational forces on Earth’s surface. With less air pressure keeping liquid molecules in their liquid form, it takes less heat in order to vaporize them—in other words, boiling points are lower at higher altitudes.

“For every 500-foot increase in altitude, the boiling point of water drops by 0.9°F,” Dr. Craig F. Morris, director of the USDA ARS Western Wheat Quality Laboratory at Washington State University, told HuffPost.

Since liquids evaporate at lower temperatures, all the moisture that makes your signature chocolate cake so dense and delicious could disappear long before you’d normally take it out of the oven. To avoid this, you should bake certain goods at lower temperatures.

With less air pressure, gases expand faster, too—so anything that’s supposed to rise in the oven might end up collapsing before the inside is finished baking. Cutting down on leavening agents like yeast, baking powder, and baking soda can help prevent this. This also applies to bread dough left to rise before baking (otherwise known as proofing); its rapid expansion could negatively affect its flavor and texture, so you might need to adjust how much yeast you’re using.

If all the ways a recipe could go wrong at high altitudes—and all the experimentation needed to make sure it goes right—seem like a lot to keep track of, Betty Crocker has a handy chart with various types of baked goods and suggested modifications for them.

[h/t HuffPost]