What's the Difference Between Mold and Mildew?

iStock.com/AndreasReh
iStock.com/AndreasReh

We’re all familiar with colorful spots of something growing in our showers and in other dark, damp areas in our homes, but you may not know what to call it. Is it mold, or is it mildew? What is the difference between the two, anyway?

Both terms refer to fungus, but as it happens, it’s a squares-versus-rectangles situation. Mildew is a type of mold. The term typically describes fungi that grows flat, on surfaces like the walls of your shower or window sills. There are also several types of mildew that are specific to plants—powdery mildew and downy mildew are parasites that grow on certain trees, flowers, and crops, for example. While mold might be a colorful green or black, mildew is typically white.

The word mildew originally came from honeydew, a term for sticky secretions aphids and other insects leave on plants, which people used to think came from the sky, like dew. Eventually, the word came to refer to the mold caused by the fungi that fed on these secretions.

Powdery mildew on maple leavesiStock.com/kazakovmaksim

Most of the household growths we refer to as mold belong to just a few families of fungi species. According to the CDC, the most common indoor molds are Cladosporium, Penicillium, Aspergillus, and Alternaria. Household molds can be a variety of colors, from orange-brown to green to gray to black. (Note that not all mold that is black in color is the more toxic species we call “black mold,” or Stachybotrys.) In contrast to the powdery texture of mildew, molds are typically fuzzy or slimy.

In nature, mold can play an important role in the ecosystem, breaking down dead plants and leaves. In your house, those decomposition abilities aren’t quite so welcome. Mold spores fly through the air, and when they land in moist places, they start to grow—whether that’s on food, your ceiling, paper products, wood, carpet, leather, or elsewhere around your house—and in the process, destroy whatever they're growing on. Unlike mildew, most molds grow down into the surface of its habitat, making them more difficult to remove. In porous materials, mold grows into all the empty crevices, which is why it is often impossible to remove all the mold from ceiling tiles (or soft foods like bread).

Mold growing in a Nashville home following a floodMartin Grube, FEMA // Public Domain

Getting rid of the unsightly growth in your damp bathroom is more than just a matter of aesthetics. Indoor mold can cause allergic reactions, such as a stuffy nose or itchy eyes, and can lead to infections for people with compromised immune systems. Some people are more sensitive to mold than others, and may experience more symptoms when exposed to it. Generally speaking, though, mold spores are everywhere, so you’re never going to live a totally mold-free life. Spores will come into your home through windows, doorways, ventilation and climate control systems, and via your clothing, shoes, and pets.

But there’s only one way to effectively inhibit mold growth at home: Get rid of the moisture. That means fixing leaks, getting better ventilation, and possibly running a dehumidifier, according to the CDC’s recommendations on mold.

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Amazon's Under-the-Radar Coupon Page Features Deals on Home Goods, Electronics, and Groceries

Stock Catalog, Flickr // CC BY 2.0
Stock Catalog, Flickr // CC BY 2.0

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

Now that Prime Day is over, and with Black Friday and Cyber Monday still a few weeks away, online deals may seem harder to come by. And while it can be a hassle to scour the internet for promo codes, buy-one-get-one deals, and flash sales, Amazon actually has an extensive coupon page you might not know about that features deals to look through every day.

As pointed out by People, the coupon page breaks deals down by categories, like electronics, home & kitchen, and groceries (the coupons even work with SNAP benefits). Since most of the deals revolve around the essentials, it's easy to stock up on items like Cottonelle toilet paper, Tide Pods, Cascade dishwasher detergent, and a 50 pack of surgical masks whenever you're running low.

But the low prices don't just stop at necessities. If you’re looking for the best deal on headphones, all you have to do is go to the electronics coupon page and it will bring up a deal on these COWIN E7 PRO noise-canceling headphones, which are now $80, thanks to a $10 coupon you could have missed.

Alternatively, if you are looking for deals on specific brands, you can search for their coupons from the page. So if you've had your eye on the Homall S-Racer gaming chair, you’ll find there's currently a coupon that saves you 5 percent, thanks to a simple search.

To discover all the deals you have been missing out on, head over to the Amazon Coupons page.

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How Do Astronauts Vote From Space?

Astronaut Kate Rubins casts her ballot from space.
Astronaut Kate Rubins casts her ballot from space.
NASA

Earlier this week, NASA announced that astronaut Kate Rubins had officially cast her vote from a makeshift voting booth aboard the International Space Station. As much as we’d like to believe her ballot came back to Earth in a tiny rocket, the actual transmission was much more mundane. Basically, it got sent to her county clerk as a PDF.

As NASA explains, voting from space begins the same way as voting abroad. Astronauts, like military members and other American citizens living overseas, must first submit a Federal Postcard Application (FPCA) to request an absentee ballot. Once approved, they can blast off knowing that their ballot will soon follow.

After the astronaut’s county clerk completes a practice round with folks at the Johnson Space Center in Houston, they can start the real voting process. The astronaut will then receive two electronic documents: a password-protected ballot sent by the Space Center’s mission control center, and an email with the password sent by the county clerk. The astronaut then “downlinks” (sends via satellite signal) their filled-out ballot back to the Space Center attendants, who forward it to the county clerk. Since the clerk needs a password to open the ballot, they’re the only other person who sees the astronaut’s responses. Then, as NPR reports, they copy the votes onto a regular paper ballot and submit it with the rest of them.

Though Americans have been visiting space for more than half a century, the early jaunts weren’t long enough to necessitate setting up a voting system from orbit. That changed in 1996, when John Blaha missed out on voting in the general election because his spaceflight to Russia’s space station Mir began in September—before absentee voters received their ballots—and he didn’t return until January 1997. So, as The Washington Post reports, NASA officials collaborated with Texas government officials to pass a law allowing astronauts to cast their ballots from space. In the fall of 1997, David Wolf became the first astronaut to submit his vote from a space station. The law is specific to Texas because most active astronauts reside there, but NASA has said that the process can be done from other states if need be.