What's the Difference Between a Router and a Modem?


Despite using it every day, the internet is still a mystery to many of its users. If asked to explain how your home internet connection works, you may start with your router and modem. Both devices are essential to setting up a wireless network, but they serve distinct functions. Here are the major differences between the two pieces of hardware that make home internet run.

What is a Modem?

Cable modem.

The modem is your home's gateway to the World Wide Web. It's often a skinny box with a row of LED icons on the front that tell you if it's on and connected to the internet. The name is short for modulator-demodulator—a phrase left over from the days of dial-up when modems worked by modulating telephone signals into frequencies that could send digital information.

Today, most modems use broadband connections like cable or satellite to transmit data. There are different types of modems built to fit different connections. If your internet service provider (ISP) uses cable or fiber internet, you'll need to plug a cable into the back of your modem, and if you still use a digital subscriber line (DSL), you'll have to plug in a phone line.

What is a Router?

Internet router.

You can connect to the internet with just a modem as long as you don't mind plugging your device directly into the Ethernet port. But if you want to provide internet to all the laptops, desktops, and smartphones in your home at the same time, you'll need a router.

Routers usually lie flat and have antennas sticking out of them. The router hooks up to your modem via an Ethernet cable and acts as a conduit between the direct internet and your home network. After connecting your devices, the router "routes" your modem's networking traffic their way, either through Ethernet wires or wirelessly through Wi-Fi (that's what the antennas are for). The router also works in the other direction by routing data sent from your computer back to the web.

Why Knowing the Difference Matters

When they've been sitting in the same spot in your home for years, it's easy to think of your router and modem as basically the same thing. But it's worth knowing the difference—especially if you care about improving your internet connection. Now that you know the router is what directs Wi-Fi signals, you can boost your home network by placing it in a central location away from electronic appliances. And as long as it doesn't interfere with the router, feel free to hide your modem behind a houseplant.

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How Do Airplanes Land in Water?


Joe Shelton:

At least in terms of the physical act of landing, seaplanes and floatplanes land on the water pretty much in the same way that land based airplanes land on the ground.

They start with an appropriate approach airspeed, a slight flaring just before touching down, feeling it as the aircraft touches the water, and then it's slightly different. Because of the water's drag the aircraft will slow very quickly and settle into the water. Brakes aren't really needed. And that's good because they don't have any brakes that work in the water.

Once in the water they are as controllable as a boat. Which is to say, not that much. In fact, in the water they are navigated pretty much just like a boat.

Most if not all seaplanes and floatplanes have "water rudders" that allow them to steer in the water just like a boat. But as they approach a pier or beach you'll usually see the engine stopped and the pilot out on the float or leaning out of the aircraft with an oar rowing the boat to shore (sounds like a Peter, Paul, and Mary lyric).

If the question wonders why the aircraft don't sink, it's because they are designed to float.

Floatplanes are typically normal aircraft that have been outfitted with floats, usually two, one under each wing. Seaplanes, on the other hand, are designed specifically for water operations.

Many or even most floatplanes and seaplanes are what's called amphibious. That means that they can land and take off from both water and land. Typically they have retractable/extendable wheels (landing gear).

While it's important that an aircraft's landing gear has been extended when landing on the ground, it's equally important, if not more so, that the landing gear is retracted when landing on water.

Here's why:

The aircraft in the video is a "floatplane" with aftermarket floats.

a firefighting seaplane
iStock/Paolo Seimandi

This is a seaplane where the fuselage is designed to float like a boat. It also has floats, but they are part of the design.

a Piper Apache floatplane
Phil Hollenback, Flickr // CC BY-NC 2.0

This is a Piper Apache on floats. It's also the aircraft that I earned my Commercial Multiengine Seaplane rating in.

This post originally appeared on Quora. Click here to view.

Why Are Barns Often Painted Red?

iStock/Ron and Patty Thomas
iStock/Ron and Patty Thomas

Beginning with the earliest American settlements and continuing into the 18th century, most barns weren't painted at all. Early American barn builders took sun exposure, temperature, moisture, wind, and water drainage patterns into account when placing and building barns, and they seasoned the wood (that is, they reduced the moisture content) accordingly. The right type of wood in the right environment held up fine without any paint.

Toward the end of the 1700s, these old-school methods of barn planning and building fell by the wayside. People sought a quicker, easier fix for preserving their barns—a way to coat and seal the wood to protect it from sunlight and moisture damage. Farmers began making their own coating from a mix of linseed oil (a tawny oil derived from the flax seeds), milk, and lime. It dried quickly and lasted a long time, but it didn't really protect the wood from mold and wasn't quite like the "barn red"we know today—it was more of a burnt orange, really.

Turning Red

The problem with mold is that it decays wood and, in large quantities, can pose health risks to people and animals. Rust, it turns out, kills mold and other types of fungi, so farmers began adding ferrous oxide (rusted iron) to the linseed oil mix. A little bit of rust went a long way in protecting the wood, and it gave the barn a nice red hue.

By the late 19th century, mass-produced paints made with chemical pigments became available to most people. Red was the least expensive color, so it remained the most popular for use on barns, except for a brief period when whitewash became cheaper and white barns started popping up. (White barns were also common on dairy farms in some parts of Pennsylvania, central Maryland, and the Shenandoah Valley, possibly because of the color's association with cleanliness and purity.)

Throughout Appalachia (a historically poorer region), many barns went unpainted for lack of money. In the tobacco regions of Kentucky and North Carolina, black and brown barns were the norm, since the dark colors helped heat the barn and cure tobacco.

Today, many barns are still painted the color traditionally used in a given region, with red still dominating the Northeast and Midwest.

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This story was updated in 2019.