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13 Scientific Explanations for Everyday Life

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Science holds our lives together. It explains everything from why bread rises to why you need gas to power your car. In his book Atoms Under the Floorboards, author Chris Woodford lays out the abstract science that underlies the everyday world, from the big (how do skyscrapers stay up?) to the small (why does my laptop get hot when I’m watching Netflix?). Along the way, he also calculates the answers to whimsical questions like, “How many people would I have to gather together to keep my house warm without heat?” (A lot, but not as many as you'd think.) Here are 13 things we learned about the world through his eyes.

1. A POWER DRILL COULD SET YOUR HOUSE ON FIRE, IN THEORY.

Because of friction, electric drills generate heat. The motor, the drill bit, and the wall all get hot. It takes about 2000 joules of energy to heat one kilogram of wood just 1°C. Assuming a typical power drill uses 750 watts of electricity, and it puts out 750 joules of energy, Woodford calculates that it would take just four minutes to set fire to a wooden wall in a 68°F room.

2. STICKY NOTES COME OFF EASILY BECAUSE THEIR ADHESIVE IS UNEVEN.

Post-it Notes feature a plastic adhesive that is spread out in blobs across the paper. When you slap a Post-it onto your bulletin board, only some of these blobs (technically called micro-capsules) touch the surface to keep the note stuck there. Thus, you can unstick it, and when you go to attach it to something else, the unused blobs of glue can take over the adhesive role. Eventually, all the capsules of glue will get used up or clogged with dirt, and the sticky note won't stick anymore.

3. GUM IS CHEWY BECAUSE IT'S MADE OF RUBBER.

Early gums got their elastic texture from chicle, a natural type of latex rubber. Now, your bubble gum is made with synthetic rubbers like styrene butadiene (also used in car tires) or polyvinyl acetate (also used in Elmer’s glue) to mimic the effect of chicle.

4. OFFICE BUILDINGS ARE EVER-SO-SLIGHTLY TALLER AT NIGHT.

After all the employees go home, tall office buildings get just a little taller. A 1300-foot-tall skyscraper shrinks about 1.5 millimeters under the weight of 50,000 occupants (assuming they weigh about the human average).

5. A LEGO BRICK CAN SUPPORT 770 POUNDS OF FORCE.

LEGOs can support four to five times the weight of a human without collapsing. They are strong enough to support a tower 375,000 bricks tall, or around 2.2 miles high.

6. POLISHING SHOES IS LIKE FILLING IN A ROAD'S POTHOLES.

Regular leather appears dull to the eye because it’s covered in teeny-tiny scrapes and scratches that scatter whatever light hits the material. When you polish a leather shoe, you coat it in a fine layer of wax, filling in those crevices much like a road crew smoothes out a street by filling in its potholes. Because the surface is more uniform, rays of light bounce back toward your eye more evenly, making it look shiny.

7. YOU COULD HEAT YOUR HOUSE WITH JUST 70 PEOPLE.

People give off body heat, as anyone who has been trapped in a small crowded room knows. So how many people would it take to warm up your home with just body heat in the winter? About 70 people in motion, or 140 people still, figuring that humans radiate 100-200 watts of heat normally and that the house uses four electric storage heaters.

8. DENSITY EXPLAINS WHY COLD WATER FEELS COLDER THAN AIR AT THE SAME TEMPERATURE.

Because water is denser than air, your body loses heat 25 times more quickly while in water than it would in air at the same temperature. Water's density gives it a high specific heat capacity, meaning it takes a lot of heat to raise its temperature even a little, and it's very good at retaining heat or cold (the reason why hot soup stays hot for a long time, and why the ocean is much cooler than land). Water is a great conductor, so it's very effective at transferring that heat or cold to your body.

9. WATER CLEANS WELL BECAUSE IT HAS ASYMMETRICAL MOLECULES.

Because water molecules are triangular—made of two hydrogen atoms stuck to one oxygen atom—they have slightly different charges on their different sides, kind of like a magnet. The hydrogen end of the molecule is slightly positive, and the oxygen side is slightly negative. This makes water excellent at sticking to other molecules. When you wash away dirt, the water molecules stick to the dirt and pull it away from whatever surface it was on. This is also the reason water has surface tension: it’s great at sticking to itself.

10. THE "PULSE" SETTING ON A BLENDER WORKS BETTER BECAUSE OF TURBULENCE.

When your blender stops chopping up food and begins just spinning it around in circles, it’s because everything inside is spinning at the same rate. Instead of actually blending ingredients together, it’s experiencing laminar flow—all the layers of liquid are moving in the same direction with constant motion. The pulse function on the blender introduces turbulence, so instead of the fruit chunks rolling around the side of the blender, they fall into the center and get blended up into a smoothie.

11. BABIES' BODIES CONTAIN MORE WATER THAN ADULTS.'

Adults are around 60 percent water. By contrast, newborn babies are about 80 percent water. But that percentage quickly drops: A year after birth, kids' water content is down to around 65 percent, according to the USGS.

12. GLASS BREAKS EASILY BECAUSE ITS ATOMS ARE LOOSELY ARRANGED.

Unlike other solid materials, like metals, glass is made up of amorphous, loosely packed atoms arranged randomly. They can’t absorb or dissipate energy from something like a bullet. The atoms can’t rearrange themselves quickly to retain the glass’s structure, so it collapses, shattering fragments everywhere.

13. CALORIE COUNTS ARE CALCULATED BY INCINERATING FOOD.

Calorie values on nutritional labels estimate the energy contained in the food within the package. To figure out how much energy is in a specific food, scientists use a calorimeter. One type of calorimeter essentially burns up the food inside a device surrounded by water. By measuring how much the temperature of the water changes in the process, scientists can determine how much energy was contained in the food.

This story originally ran in 2015.

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MARS Bioimaging
The World's First Full-Color 3D X-Rays Have Arrived
MARS Bioimaging
MARS Bioimaging

The days of drab black-and-white, 2D X-rays may finally be over. Now, if you want to see what your broken ankle looks like in all its full-color, 3D glory, you can do so thanks to new body-scanning technology. The machine, spotted by BGR, comes courtesy of New Zealand-based manufacturer MARS Bioimaging.

It’s called the MARS large bore spectral scanner, and it uses spectral molecular imaging (SMI) to produce images that are fully colorized and in 3D. While visually appealing, the technology isn’t just about aesthetics—it could help doctors identify issues more accurately and provide better care.

Its pixel detectors, called “Medipix” chips, allow the machine to identify colors and distinguish between materials that look the same on regular CT scans, like calcium, iodine, and gold, Buzzfeed reports. Bone, fat, and water are also differentiated by color, and it can detect details as small as a strand of hair.

“It gives you a lot more information, and that’s very useful for medical imaging. It enables you to do a lot of diagnosis you can’t do otherwise,” Phil Butler, the founder/CEO of MARS Bioimaging and a physicist at the University of Canterbury, says in a video. “When you [have] a black-and-white camera photographing a tree with its leaves, you can’t tell whether the leaves are healthy or not. But if you’ve got a color camera, you can see whether they’re healthy leaves or diseased.”

The images are even more impressive in motion. This rotating image of an ankle shows "lipid-like" materials (like cartilage and skin) in beige, and soft tissue and muscle in red.

The technology took roughly a decade to develop. However, MARS is still working on scaling up production, so it may be some time before the machine is available commercially.

[h/t BGR]

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ESA/Herschel/SPIRE; M. W. L. Smith et al 2017
Look Closely—Every Point of Light in This Image Is a Galaxy
ESA/Herschel/SPIRE; M. W. L. Smith et al 2017
ESA/Herschel/SPIRE; M. W. L. Smith et al 2017

Even if you stare closely at this seemingly grainy image, you might not be able to tell there’s anything to it besides visual noise. But it's not static—it's a sliver of the distant universe, and every little pinprick of light is a galaxy.

As Gizmodo reports, the image was produced by the European Space Agency’s Herschel Space Observatory, a space-based infrared telescope that was launched into orbit in 2009 and was decommissioned in 2013. Created by Herschel’s Spectral and Photometric Imaging Receiver (SPIRE) and Photodetector Array Camera and Spectrometer (PACS), it looks out from our galaxy toward the North Galactic Pole, a point that lies perpendicular to the Milky Way's spiral near the constellation Coma Berenices.

A close-up of a view of distant galaxies taken by the Herschel Space Observatory
ESA/Herschel/SPIRE; M. W. L. Smith et al 2017

Each point of light comes from the heat of dust grains between different stars in a galaxy. These areas of dust gave off this radiation billions of years before reaching Herschel. Around 1000 of those pins of light belong to galaxies in the Coma Cluster (named for Coma Berenices), one of the densest clusters of galaxies in the known universe.

The longer you look at it, the smaller you’ll feel.

[h/t Gizmodo]

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