Demographic definitions and key terms

A video introduction to demography

The Big Think’s video provides a thorough introduction to the field of demography. Demography provides the tools to address and understand many of the world’s problems. It uses quantitative data and mathematical models to analyze populations....

Everything you need to know about demography in 10 graphs

This 17-minute video explains the future of the world through demographic data points. Dr. Paul Morland has published three books on demography. In this talk, he shows how demography is a powerful lens to view global transformations. Included are...

The World Bank’s population data bank

This website by the World Bank provides visualizations for demographic data from around the world. Specific demographic data, such as total population, can be viewed through maps, charts, and graphs. Results can be filtered by sex, country, or year....

How public policy shapes demographic trends

This IMF podcast explores the population booms and busts throughout human history. According to Harvard economist and demographer David Bloom, it took more than 50,000 years for the world population to reach 1 billion. But since 1960, we have added...

Health and population surveys from 90 countries

The Demographic and Health Surveys (DHS) Program collects, analyzes, and disseminates data on population, health, HIV, and nutrition. The site compiles data through more than 400 surveys in over 90 countries around the world. Explore demographic...

How demographics influence voter turnout and elections

This article breaks down demographic data to show what it means for American elections. According to the latest US Census, the US is growing increasingly diverse. As the population becomes more diverse, so does the electorate. Analyzing the...

Four global trends in shifting demographics

This UN summary outlines four global trends in shifting demographics. The world’s population is expected to peak by the end of the century as fertility rates continue to decline. Between now and 2050, the global population is projected to become...

Mortality tables help determine the probability of death for specific populations

A mortality table is a diagram that helps predict a specific population’s likelihood of death within a particular time period. Life insurance companies often use them to help figure out pricing for their insurance products. They’re sometimes known as actuarial tables or life tables.

Chronological versus biological age

Science has come to understand different types of aging. What we call age is simply the number of years since birth, or chronological age. At the cellular level, biological aging happens at different rates for different people, and explains why some seem to age more quickly (or slowly).

40 key stock market terms, explained

Liquidity. Forex. Capitalization. Blue chip stocks. These are just a few pieces of stock market vocabulary most people who don't spend all day on a trading floor might not know. Thankfully, we found a fun infographic that makes it easier to learn what 40 key stock market terms mean and why each of them matters.

One signal that a recession has become a depression? When GDP declines more than 10%

There’s no single definition for recessions or depressions, but both are marked by sustained periods of declining economic activity. Depressions are more severe than recessions.

What is a microbiome (and why are they important)?

Jump to: What is the microbiome? How microbiota benefit the body The role of probiotics Can diet affect one’s microbiota? Future areas of research What is the microbiome? Picture a bustling city on…

An analysis of the logistic map, which shows how chaos can emerge from simple equations

When modeling systems such as the predator-prey cycle of an organism's population in an ecosystem, the logistic map function shows the population normally settles into an equilibrium value. However, at high reproduction and starvation rates, multiple such values arise, making it difficult to accurately model long-term population growth in some environments.

Opera terminology heavily relies on Italian

Most commonly used Opera terms are not in English. This glossary provides definitions of keywords like “libretto,” the text of a piece, “tenor,” the highest natural adult male singing voice, and “diva,” a female opera star.

In 1968, a Harvard Medical School committee issued the first neurological definition of death

The definition set a legal and medical precedent for how we define death, important for issues including organ donation. This 2020 video podcast discusses the history of brain death controversies and the variability in how death has been determined, including discussions in the late 1960s about when patients are considered dead in the context of organ donations.

What is a cell? A great quick overview.

YourGenome.org furnishes a collection of information on cells and how they work. Every body has trillions of cells, each serving a specific function: making proteins, processing chemicals, and creating energy. Every cell contains a genome, a set of instructions for the cell's function. Brush up on your cells for a better grasp on genetics.

What exactly is a GMO?

A GMO, or genetically modified organism, is an organism whose DNA has been altered for specific improvement such as longer shelf life, disease resistance, or enhanced nutrition—which can benefit both farmers and consumers. While humans have used...

Fetal development, week by week

Gestation is the period of time between conception and birth when a baby grows inside the mother's womb. Changes occur constantly over the course of these 40 weeks. At week 17, for instance, the skeleton of a fetus begins changing from soft...

North Korea country profile

North Korea has often been described as one of the world’s most secretive societies. Learn the basics about the Democratic People’s Republic of North Korea with this breakdown from the BBC. North Korea emerged in 1948, following the end of the Second World War. Today, it remains one of the few countries still (nominally) under communist rule. Key facts unpack the realities of everyday life inside North Korea.

An encyclopedia of anthropology

This online database offers articles and additional resources for all things anthropology. This free resource is filled with peer-reviewed entries that cover topics ranging from addiction to writing, and offers anthropological insight into more...

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.

Being a 'digital nomad' has become more common since the pandemic popularized remote work

Digital nomads are people who often work remotely without a specific home base, traveling from country to country or city to city, often without returning to a home address in-between.

The Köppen-Geiger system divides Earth’s climate into five main categories

This classification system, developed by a German-Russian botanist and a German climatologist, results from differences in the intensity of solar radiation and rainfall in different parts of the world. Each category is further divided into multiple coded zones.

The R0 value is how epidemiologists quantify disease contagiousness

The basic reproduction number indicates the average number of people a person with a disease will infect. Measles is the most contagious disease, with an R0 of 12-18, though vaccines have significantly reduced the number of susceptible individuals.

Defining an indie film

Indie movies have a definite history, but the use of the word by contemporary audiences can be vague. This brief explainer goes into a few tiers of indie film and a quick historical overview.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Explore an interactive map built from more than 100,000 survey responses on where people find joy in their lives

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

A century of Billboard issues documenting the evolution of popular music.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

Lesser-known phobias include turophobia, or the fear of cheese, and nomophobia, the fear of being without your cell phone.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

An initial public offering or 'IPO' is the process of a private company becoming public by putting shares of the company on the stock market for purchase.

Calculate how much of your tax dollars go to each federal program based on your income, filing status, and number of children

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

See a 3D reconstruction of Tenochtitlan, the Aztec capital that was home to an estimated population of 200,000 to 400,000.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Graffiti dates back to at least ancient Pompeii, where citizens scrawled messages to one another on public walls

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

See how Ebola tore through Guinea, Sierra Leone, and Liberia in 2014-2016.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

Meet the 56 signers of the Declaration of Independence—most of whom didn't put pen to paper until August 2, 1776—and see their original signatures.

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.