What's the difference between an ocean, sea, and saltwater lake?

A simple pictorial explanation of ocean geography

Visualizing ocean geographical features, such as a coastal zone, continental shelf and abyssal plain. This article from the US Geological Survey also provides several links to diverse ocean facts.

Geodesists define sea level using gravity rather than the ocean's height

The sea level is not the same everywhere because the Earth isn't perfectly spherical or has a uniform composition and density. Earth's gravitational field is carefully measured to determine where the sea level would be, even in places with no water.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

What animals live in the ocean?

The oceans host an incredible diversity of fascinating species. Oceana's Marine Life Encyclopedia beautifully presents facts and photos of ocean animals from Atlantic Cod to Zebra Sharks.

How flooding the Dead Sea could help the climate

There are many dead zones in the world with low elevation and very little rainfall that provide little to no benefits to the ecosystem or climate. This digestible, thorough article explains how piping in nearby water to flood these areas could...

Data-packed infographic on Earth's oceans

Did you know more than 200 million people live on land that could be flooded by rising sea levels? Learn fascinating facts about the ocean from this data-filled infographic from the Woods Hole Oceanographic Institute.

Why is sea level rising?

Rising global sea level is one of the most commonly cited consequences of climate change, but it’s often unclear how it might affect people living on the coasts. Read this explanation of why global sea level is rising and why sea level rise happens at different rates in different locations.

How Oceans were formed

Nonprofit organization American Oceans briefly explains the formation of the oceans, which cover over two thirds of Earth’s surface. They were formed by centuries of rain from the condensation of Earth's original gasses.

The 10 most amazing deep sea creatures

In this video, researchers from the world-renowned Monterey Bay Aquarium discuss the most fascinating deep sea creatures, and how they developed some of their strangest features.

Salt is harvested from briny ocean water and underground deposits

Mostly sodium chloride, this compound is produced for human use by collecting seawater in shallow pans and allowing the Sun to evaporate the water until crystals remain. Underground rock salt is mined, crushed, and purified from deposits left behind by ancient seas that have dried-up.

Distinguishing club soda, seltzer, and sparkling water

The three forms of drinking water are similar, but their differences lie mostly in the presence and proportion of minerals and carbonation. Read this quick explainer on the major differences.

Visualizing changes in ocean temperatures between 2016 and 2020

How much does the temperature of the sea change in a given year? This visualization helps illustrate the changes by showing sea surface temperature data from January 2016 through March 2020. Sea surface temperature, which refers to water temperature at the sea's surface, plays a significant role in climate and weather.

Desalination involves costly, energy-intensive methods for producing freshwater

Thermal desalination heats saltwater to produce steam, and reverse osmosis forces saltwater through a membrane that only allows water through. In both cases, freshwater is collected and remineralized for consumption, while wastewater brine is often returned to the ocean, where it may harm marine organisms.

38 thought-provoking facts about the ocean

Coral produces its own sunscreen, tsunamis move at 500 miles per hour, one of the loudest sounds ever recorded came from an ice quake, and other interesting facts collected from sources such as National Geographic and NASA.

Hot, semiarid, coastal, cold: An overview of the four desert types

This article describes the various characteristics of deserts, including their geography, their climate, their soil, and the wildlife and vegetation that inhabit them. All desert climates are characterized by extreme temperatures and low rainfall,...

How five of the world's most expensive salt and spices are made

Part of the charm of certain spices and salts is their exotic origin, hailing from difficult-to-access locales or hewn via special processes. That also explains why they can be so expensive. Dive into the businesses of producing and marketing five of the world's most expensive food additives with this engaging video.

How salt, sunlight, and wind drive ocean currents

The Atlantic Meridional Overturning Circulation plays a critical role in regulating earth's climate, but is threatened by climate change. Explore the effects of temperature, density, and salinity on ocean currents in this 13-minute PBS video.

A chemical overview of water, whose uncommon properties help sustain life on Earth

The uneven distribution of charge in water molecules allows them to bond to each other and to surfaces, enabling them to move against gravity, including up plants through roots and stems. These bonds also keep water in a liquid state over a wider temperature range and make it less dense as it freezes. This causes ice to float and form an insulating layer for underwater ecosystems, from which all life originated.

What's the difference between an ale and a lager?

The major distinction is that ales are typically fruitier, while lagers are cleaner and crisper. This video breaks down several more of the nuanced differences between the two styles.

The difference between solstice and equinox, explained

A solstice marks the extremes in the amount of day or night, while the equinoxes come on days with a balance between the two. Learn why with this brief video.

NASA explores Earth's deepest oceans to prepare for space

By studying extreme environments in Earth's hadal zone—the deepest part of the ocean —NASA tests technologies, probes life under crushing pressure, and gathers clues about potential oceans and possible life on worlds like Europa and Enceladus.

Distinguishing the three types of mineral deposits collected via deep-sea mining

The greatest interest is in polymetallic nodules—structures formed from metals in seawater collecting around a core of shell, bone, or rock. Cobalt-rich ferromanganese crusts cover underwater mountain ranges and form over millions of years of metal deposition. Polymetallic sulfide deposits accumulate when seawater seeps into volcanic rocks.

A fast explainer on every Winter Olympic sport

Slalom, luge, skimo: The 16 sports at the Winter Olympics aren't the most familiar to everyday audiences. They can be divided into three categories: track, indoor, and outdoor. This video breaks down each sport's rules and quirks and the variations of its events in less than eight minutes.

The Great Lakes hold almost 20% of the world's surface freshwater

Formed by retreating glaciers, the Great Lakes system feeds Niagara Falls through the Niagara River. Together, the lakes contain about 23 quadrillion liters (5,400 cubic miles) of water, enough to cover the land portion of the continental US to a depth of 3 meters (9.84 feet).

Moon 101: NASA's complete overview of our lunar companion

From modulating our tides to impact our climate, Earth's lone natural satellite plays a key role forming the planet's habitat. Before diving into the rest of the resources on this page, check out NASA's overview of the basics of the Moon—how it got its name, its size and distance from Earth, its structure, and much more.

It's called kosher salt because it works for curing kosher meat

Kosher foods align with Jewish religious customs based on scripture. While there is a type of salt that is kosher (most often, salts without iodine), the kosher salt you see around the US is actually big, flaky salts used in a kosher process of curing meats.

Monsoons are large, seasonal shifts in wind driven by land-sea heating differences

Because land heats and cools faster than water, pressure differences form and create significant sea breezes. Moist air pulled onto land rises, condenses, and leads to substantial summer rainfall.

The difference between ice cream, gelato, sorbet, and Italian ice

Ice cream is made of eggs and is high in fat, served cold. Gelato, on the other hand, has more milk and less cream, and is typically served warmer than ice cream. Sorbet is dairy-free and often includes alcohol, while Italian ice is grainy, lighter, and low in calories (and often doesn't contain dairy).

The best beach in every US state

Not every state has coastline, but every state has a beach. This list highlights the best sandy shorelines in every US state, whether near the ocean, a lake, or a river.

Why are all maps of the world wrong?

This 5-minute video explains why all maps to date are verifiably wrong. While globes can provide an accurate map and scale of the various continents, flattening that sphere has historically meant something will be distorted, whether land, sea, or...

Video and still images are combined with sonar data to create seafloor maps

Sonar works by sending thousands of sound pulses per second towards the seafloor, capturing the strength and timing of the returning echo. This data can accurately reveal depth, seafloor texture, and the presence of fish habitats to millimeter resolutions.

Wrestling terms you need to know

Wrestling may be scripted, but it’s built on its own vocabulary. From "babyfaces" and "heels" to "kayfabe" and "finishers," this explainer breaks down the key terms that shape what fans see in the ring—and what’s really going on behind the scenes.

Here's how the seven types of plastics fare in the recycling process

To help you make better-informed decisions about the products that you buy, here's a simple explanation of the seven different types of plastic, how they differ, and their impact on the environment.

Why the ratios of helium isotopes are analyzed to investigate ocean circulation

Volcanic activity on the seafloor produces high ratios of helium-3 to helium-4, which can be tracked in ocean samples more easily than other elements because helium is nonreactive. Water from deep ocean currents can also be distinguished from air-exposed surface water sources by comparing these ratios, since atmospheric helium ratios are much lower.

How the loss of Earth's atmosphere would cause oceans to boil at freezing temperatures

Many phenomena requiring air pressure, from the flight of birds and aircraft to the act of breathing, would no longer be possible. Because sound travels through vibrating air molecules, the loss of the planet's atmosphere would also create a silent environment. Even during daytime hours, the sky would resemble a clear night sky.

The ingredients that make up severe weather

A seven-minute video illustrating how a storm is made. These factors—moisture, instability, lift, and shear—are explained through a series of data sets and creative, descriptive diagrams.

The '7 Summits' is a challenge featuring every continent's highest peak

Some devoted mountaineers aim to tackle the seven highest summits in the world: Mount Everest (Asia), Aconcagua (South America), Mount McKinley (North America), Mount Kilimanjaro (Africa), Mount Elbrus (Europe), Mount Vinson (Antarctica), and either Mount Kosciuszko or the Carstensz Pyramid (Oceania).

The seven major US freight rail companies

The US railroad industry is dominated by seven long-running freight conglomerates. Get the basics on each of these companies with this brief overview.

View examples of rift valleys, the product of surface divergent boundaries

At these boundaries, tectonic plates move apart, stretching and thinning Earth’s crust as long valleys are formed from smaller, interconnected valleys and troughs. Ongoing rifting and erosion can further sink the valley, becoming a rift lake if volcanic activity becomes inactive.

A deeper walk through of the four stages of sleep

In this TED video, sleep expert Matthew Walker carefully breaks down the sleep stages along with a description of why each is important. He finishes the discussion by examining the consequences of altered or decreased sleep, and why seemingly small alterations in our sleep patterns can have outsized effects.

Understanding the distinctions between coffee types

If you’ve ever felt overwhelmed looking at a coffee shop menu, you're not alone. Here's a breakdown between common coffee styles. Click through the link to see similar guides to espresso and cold drinks.

A guide to white wine

Aside from color, how does white wine differ from red? This comprehensive guide to white wine covers everything from grape varieties to production methods to aging techniques. It provides explanations for several common white wine blends as well. You'll also discover an overview of tasting notes for several popular white wines, and suggestions for foolproof food pairings like brie and Chardonnay.

The four types of seismic waves are categorized as body or surface waves

Primary (P) and secondary (S) waves are compression and shear waves, respectively, and travel through Earth’s interior, though secondary waves only move through solids. These waves’ energy is converted into rolling Rayleigh or horizontal Love waves at the surface.

Mosquito-borne illnesses have killed captive orcas at SeaWorld

After two SeaWorld orcas died from viruses carried by mosquitoes, scientists warn that mosquito-borne illnesses may be a bigger threat to these captive animals than previously known. Captive orcas spend a lot of time stationary, close to the surface, unlike their wild counterparts. Researchers saw mosquitoes landing on the animals' backs, heads, and dorsal fins, supping on their blood.

With the exception of Earth, the planets are named after Roman gods and goddesses

Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune are named after the messenger of the gods, the goddess of love, the god of war, the king of gods, the god of agriculture, the god of the sky, and the god of the sea, respectively. "Earth" comes from Old English and Germanic words meaning "ground."

Compare various El Niño-Southern Oscillations using maps of atmospheric and ocean variables

Because the intensity of the phases in the cycle is sensitive to small variations in atmospheric and ocean conditions and depends on complex interactions between these two systems, no two El Niño or La Niña events are identical. This contributes to the variability in the length of each phase, which is why an ENSO can last as little as two years or as long as seven.

A comprehensive taxonomy of American tacos

Tacos may be a Mexican food, but they're wildly popular in America and in a number of different styles. This lengthy guide from Serious Eats was compiled after visiting more than 1,000 taco shops. It breaks down the differences between the many variations on the form (including breakfast, barbacoa, and Deli Mex) you'll encounter in different regions of the country. We don't recommend reading on an empty stomach!

What happens when a whale dies and falls to the ocean floor

A large whale's body can blanket more than 538 square feet of ocean floor. That's an enormous amount of organic matter, providing food for the ecosystem for centuries. Researchers have discovered bones on the seafloor from whale species that have been extinct for over 100,000 years.

What's the difference between a stock and a share?

While the words "stock" and "share" are often used interchangeably in casual conversation, they have different meanings. For instance, "stock" is more general, whereas "share" is more precise.

13 unanswered questions about black holes

Here's a quick rundown on black hole basics, the cosmic enigmas digesting massive swaths of the universe and destabilizing our fundamental ideas of space, time, and matter. Learn how they got their name, what happens in the unfortunate instance you fall into one, and more with this list of 13 questions about black holes.