Distinguishing polar and nonpolar molecules and why charges get distributed unevenly in molecules

Understanding how atomic structure contributes to each element's properties

The outermost layer of electrons in an atom dictates how it will bond to other atoms. These bonds determine whether elements exist as solids, liquids, or gases in the environment and other characteristics. For example, electrons are freely shared between atoms in metallic bonds, allowing them to immediately re-emit light that strikes them, thus making most metals shiny.

How geometry and uneven charge distribution make some molecules greenhouse gases

Molecules vibrate and rotate with different frequencies based on their elemental composition and shape, which can produce uneven distributions of electrons, as seen in carbon dioxide and water. The resulting unbalanced electric field can interact with electromagnetic waves of the same frequency, causing the molecule to absorb the radiation.

Why water is the universal solvent, despite not being good at dissolving many substances

Because oxygen attracts electrons much more strongly than hydrogen does in H₂O, the molecule is polar, with a negative charge at the oxygen atom and positive charges at the hydrogen atoms. These charged regions can attract and pull apart charged portions of other polar molecules, such as washable inks, but are unable to dissolve nonpolar materials, such as glass and asphalt.

How chemical bonds between atoms form molecules and large geometric structures

In ionic bonding, one atom transfers at least one electron to another atom, forming two atoms of opposite charge. These atoms attract one another and can stack up in a 3D grid called a lattice. Covalent bonding, where electrons are instead shared, can produce enormous molecules, such as the two found in human chromosome 13, which each contain 37 billion atoms.

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.

How the number of subatomic particles helps identify different types of atoms

Different elements, such as oxygen and nitrogen, can be distinguished by the number of protons in each, since all atoms of the same element have the same number of protons. Isotopes of a given element have the same number of protons but different numbers of neutrons, while ions are atoms possessing different numbers of electrons than protons.

Learn why magnets, like statically charged balloons, can deflect water

While the oxygen atom in water molecules strongly attracts hydrogen's electrons—producing an uneven charge distribution that pulls water toward balloons that have been rubbed against surfaces—the presence of a magnetic field alters the path of these electrons, which produce their own tiny magnetic fields. The interaction of these fields repels water away from magnets, making it diamagnetic.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Why most atoms do not spontaneously break apart, despite protons repelling one another

At small scales, the strong nuclear force overwhelms electromagnetic repulsion between positively charged particles, keeping the nucleus intact. However, because the force's range is limited, it cannot provide the attraction needed to hold onto protons that are spread out across very large atomic nuclei.

Batteries store energy in chemical bonds that can be turned into electricity

To achieve a more stable, nonreactive state, many elements in nature are reactive and will seek to lose electrons via oxidation or gain electrons through reduction reactions. By pairing an oxidizing chemical with a reducing chemical in a battery, electrons will naturally flow between them, producing an electric current.

The one-electron theory describes the universe as having only one electron

The thought experiment explains why every electron has the same charge and mass as every other electron, and describes every positron—the antimatter version of the electron—as that same electron traveling backwards in time. Among other foundational challenges, the model suggests that the universe contains equal numbers of electrons and positrons, yet normal matter is much more common than antimatter.

Electromagnetic repulsion prevents objects from making contact with one another

The feeling of touching something is a sensation caused by the electromagnetic force between the electrons on the surface of objects. Since this force grows to infinity with proximity, no two surfaces can ever achieve matter-to-matter contact.

Plasma is the most abundant form of visible matter in the universe

When electrons are stripped from neutral atoms as a result of high-energy interactions, such as lightning strikes, the atoms become positively charged ions. The mix of these ions and negatively charged electrons, which are too energetic to recombine, is extremely electrically conductive and affected by magnetic fields.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Magnetism comes from quantum properties of electrons aligning in specific structures

Permanent magnets exist because electrons have an intrinsic magnetic moment, which can align in certain atoms. When many such atoms line up their magnetic fields within regions called domains, the result is a visible, macroscopic magnetic effect.

Debating whether water is or is not wet depends on one's definition of wetness

If defined as a liquid sticking to a surface, then water itself is not wet. The sensation of "wetness" arises from water molecules latching onto an object. This occurs because water is a polar molecule possessing local regions of positive and negative charge that are attracted to charge imbalances on the surface of materials.

Lithium can store and deliver substantial energy for its cost and weight

When exploring which compounds would be best suited for batteries, scientists sought elements that were relatively inexpensive to mine, readily available, and that provided high energy density—how much chemical energy an element could store for its size. Lithium-ion batteries provide these benefits and discharge at very low rates when unused.

Similarities in reactivity complicate separating rare earths from ores

The proximity of these elements in the periodic table mean they have similar electron structure and require complex separation processes during processing. However, their uncommon magnetic, luminescent, and electrical properties make them invaluable for critical industrial applications.

Nitrogenous bases connect like puzzle pieces due to their shape

There are four bases—adenine, thymine, cytosine, and guanine—which keep the two strands of DNA connected via chemical bonds between them. Connections between thymine and adenine require two hydrogen bonds, while those between cytosine and guanine need three hydrogen bonds. These differences in bond number prevent non-complementary pairings.

Why are there as many males as females?

Pretty much every species breaks down with an equal sex-ratio, with roughly the same number of males as females. But on the surface, it appears that most species wouldn't need many males to keep the population growing, with their energy-efficient, abundant sex cell production. So why is it equal? Scientists argue an equal ratio is the most evolutionarily stable. Learn about this quirk of biology here.

Twin studies helped scientists understand why mosquitoes like some of us more than others

A combination of carbon dioxide output, skin chemistry, genetic factors, hormones, and clothing choice can make us particularly vulnerable to mosquito bites. Watch how mosquitoes responded to one man in the video versus his wife, a research approach typically conducted with identical and fraternal twins to test mosquito attractiveness.

View the various types of lightning

The most common form of lightning involves channels of electricity between oppositely charged regions within a cloud or between two clouds to reestablish electrostatic equilibrium. While cloud-to-ground lightning is understood best, research is ongoing to fully model the mechanisms behind rarer forms of lightning, such as transient luminous events.

Aurora borealis and auroras australis do not always mirror one another

While the Earth's magnetic field is symmetric across the magnetic north and south poles in isolation, charged particles from the sun distort the field. If the angle of impact between the wave of particles and the Earth's field is such that the distortions are uneven, dissimilar geomagnetic storms and resulting auroras are produced in the northern and southern hemispheres.

The properties of helium, which has the lowest boiling point of any element

The colorless, odorless, mainly unreactive element condenses from a gas into a liquid at -268.928 degrees Celsius (-452.07 degrees Fahrenheit)—near the lowest theoretically possible temperature—allowing it to serve as a liquid coolant in machines without the risk of causing damage as a solid.

Juno has revealed Jupiter’s polar cyclones, complex atmosphere, and diffuse core

The continent-sized cyclones at Jupiter’s poles generate strong winds and ammonia-laden storms. The spacecraft has also collected data on Jupiter’s unique magnetic field, which resembles a blend of Earth’s and Uranus/Neptune's.

Explore a simulation of ideal gas behavior, which can be explained by kinetic molecular theory

The theory describes particles as moving in random directions, with a distribution of velocities determined by the gas's temperature. The particles collide elastically like billiard balls, are negligibly small, and do not exert forces on one another. The gas laws can be derived from these principles using statistics or observed via this interactive.

Charge cards are different from credit cards

Unlike credit cards, charge cards often don’t have a preset credit limit, but cardholders need to pay off the entire balance every month.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

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.

See how fireworks are made and learn how metals like magnesium and copper are responsible for different colors.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

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.

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.

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

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.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Dozens of S&P 500 stocks, including Coca-Cola and Walmart—known as the dividend aristocrats—have increased dividends every year for 25 years

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

Netflix profits when you're not watching, and its movies are designed that way—read a detail-rich critical essay exposing lesser-known Netflix takes

When a Paris department store hesitated to sell Estée Lauder's perfume, she 'accidentally' broke a bottle, causing the smell to spread throughout the store and shoppers to start asking to buy the scent.

This poison ivy knowledge quiz—accompanied by photos of the plant's varied forms—may help you identify this common rash-inducing growth.