In osmotic power systems, the natural movement of water from regions of low to high salt concentration is used to generate electricity from pressurized water.

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.

Some geothermal power plants make electricity using a secondary fluid

Direct dry-steam systems pull underground steam into a turbine-generator system, while flash and double-flash cycle systems spray extracted liquid water into a low-pressure tank, causing it to rapidly vaporize—"flash"—before moving to the turbine. Binary cycle systems use the extracted steam and water to flash a second fluid that easily boils, which then drives the turbine.

Concentrated solar power systems focus sunlight in order to boil water

These systems use thousands of mirrors to reflect sunlight onto a central tower storing molten salt or multiple receivers housing heat transfer fluid that absorbs the radiation. The material is pumped through water to boil it, creating steam that drives a generator.

Sand 'batteries' can store excess electricity from the power grid as thermal energy

Energy collected from solar or wind power is used to heat insulated silos full of sand to temperatures as high as 450 degrees Celsius (842 degrees Fahrenheit), which can be retained for long periods. These thermal energy storage systems can be designed to boil water and generate electricity when needed.

Visualize how alternating currents—electricity that periodically changes direction—are generated by rotating magnetic fields, as occurs in turbine-generator systems.

Windmills can be designed to pump groundwater for irrigation or land drainage

A gearbox within the windmill converts the windmill's rotation into the vertical motion of a piston that pushes water up a pipe. It also drives the rotation of an Archimedes screw to move water to higher elevations.

Geothermal power can generate electricity and provide direct heating for homes

By drilling several kilometers through penetrable rock, wells can access highly pressurized groundwater warmed by thermal energy trapped beneath Earth's surface. This water can be turned into steam to create electricity in generators. Heating systems several meters deep can pump fluid underground before circulating it through buildings.

Electrogenic animals generate their own electricity within an electric organ by changing the pattern of electrical charges in disc-shaped cells called electrocytes.

Rain-catching tubes provide new hydropower source for tropical regions

An experiment in Singapore showed that charge separation could be established by rainwater flowing through narrow tubes. The separation, which creates a voltage, could be scaled up in regions of high rainfall to provide a clean energy source.

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

In the photovoltaic effect, light generates electricity by creating a charge imbalance after knocking electrons out of atoms from semiconducting materials.

Enhanced geothermal power systems can trigger earthquakes by injecting fluid into rock, increasing subterranean pressure.

On average, the human body produces about 100 watts of electricity—enough to power a light bulb—but some people can produce over 2,000 watts in short bursts, such as when sprinting.

Electricity is produced when the ends of a battery are connected by a conducting wire, triggering chemical reactions that release the energy stored in chemical bonds.

If two strands of conducting materials are connected at two junctions, electricity can be generated if one junction is heated while the other is cooled—a phenomenon known as the Seebeck effect.

The moon's gravity pulls water from Earth's poles to produce tides

By attracting all parts of the Earth to varying degrees based on their distance from it, the moon produces an overall pressure that drives water toward the opposite sides of the Earth along the Earth-moon axis, not unlike how squeezing a grape causes it to bulge. This creates high tides along the axis on opposite sides of the Earth and low tides along the perpendicular axis. Without significant water to displace, most lakes do not experience noticeable tides.

An overview of oxygenic photosynthesis, which releases oxygen from breaking down water

Within the membranes of chloroplasts, electrons in pigments are energized by light and transferred across a series of molecules until they create the energetic NADPH molecule. This transfer also powers a hydrogen pump, which creates an ion imbalance that, when relieved, produces energetic ATP molecules. Outside the membranes, both NADPH and ATP are used to synthesize G3Ps, which are funneled into other metabolic pathways to produce sugars.

How to make your own DIY ionic thruster

In the search for more efficient, sustainable types of propulsive thrust, scientists have dabbled in developing engines using ionic thrust, a type of propulsion using the attractive force of oppositely charged ions. First introduced by a Russian...

Watch a timeline of the history of electricity, from observations of static electricity in antiquity to the War of the Currents between Nikola Tesla and Thomas Edison to establish the ideal system for electric grids.

Solid-state batteries substitute the fluid electrolyte layer with a solid

The non-flammable solid greatly reduces the risk of fire and explosion, as well as the release of toxic gases via leaks in the existing sulfide-based systems. These batteries use garnet-type solid electrolytes, which provide high ionic conductivity and chemical stability but require temperatures above 1,000 degrees Celsius (1,800 degrees Fahrenheit) for fabrication.

Solar energy alone can fully power the world if transmission hurdles can be resolved

When light strikes a photovoltaic cell, electrons are loosened, which travel through a circuit where the energy can be used. Distributing energy from high solar intensity regions and storing energy for non-daylight hours is logistically challenging and costly.

Solar sails use light as a means of propulsion

Photons possess momentum and can transfer it to objects they strike or bounce off, imparting radiative pressure, or a light-based force over a small surface area. Lasers fired at observational equipment with specially designed sails can theoretically use this mechanism to accelerate up to 20% the speed of light.

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.

The Alhambra’s medieval water system powered a palace-city

Built over centuries by Islamic rulers in medieval Spain, the Alhambra used canals and pressurized tanks to move water throughout the complex. Its sophisticated system supplied fountains, baths, and gardens, showcasing advanced medieval engineering.

Explaining the engineering challenges of extracting metal-rich nodules from the seafloor

Proposed solutions for collecting these potato-shaped rocks involve lifting a slurry composed of them, organic debris, and water through several kilometers of flexible tubing to a ship on the surface, a process that is more difficult than pumping crude oil. One method would use compressed air, but this method is only 15% energy-efficient.

Explore an interactive graphic of a wind turbine's components

Wind turbines contain a gearbox that increases the rotation of the blades by a factor of 100 from low to high-speed shafts. The latter moves magnets that change the magnetic field within a generator, creating electricity.

How water pressure affects the body

The extreme conditions of the deep sea include increasing amounts of pressure as explorers and organisms descend into its depths. The major danger for both fish and humans is the way pressure changes how body tissues absorb chemical molecules...

Movement of molten metal around its solid inner core creates Earth's magnetic field

According to the geodynamo process, the rotation of the planet and the looping, convective flow of electrically conductive iron and nickel produce dynamic electric currents, which generate a self-sustaining magnetic field. This is unlike natural, stationary magnets, which possess a static field created when the metal cooled and its atoms aligned with Earth's magnetic field.

Transformers change the current and voltage across a set of wires by wrapping them around a magnetic core and using the magnetic field of one wire to induce a current in the other.

Wireless charging uses a magnetic field to move charged particles in a battery

Based on the concept of electromagnetic induction, when a compatible device is placed on a charging pad with correct alignment, the alternating current flowing through the pad creates a changing magnetic field. This magnetic field induces a current in the device, recharging the battery without a connecting wire.

Scientists have collected critical minerals from ocean water using seaweed, a type of algae that leaves behind a mineral-rich powder called bio-ore after being processed into biofuels.

Nuclear batteries generate electrical currents using radioactive materials

Rather than using electrochemical reactions to produce the electrons that flow through a circuit, isotopes like nickel-63 undergo beta decay—emitting electrons—which a semiconducting material can absorb to establish a charge imbalance that generates current. Such batteries could provide low-power energy for decades.

Why Water Towers Are Built This Way

A solar-powered device with googly eyes is pulling trash from Baltimore's harbor

Mr. Trash Wheel uses a conveyor belt to scoop debris from the surface of Baltimore's Inner Harbor before it reaches the Chesapeake Bay, and it runs on a combination of water current and solar power.

Lightning rods provide a conductive pathway to safely steer massive electric currents

The device is positioned higher above the ground to "catch" one of the many branching filaments of electrons from clouds before they make contact with other surface structures, which have been induced to have a positive charge by overhead storm clouds. The current is then sent to a conductive grid buried underground.

Electromagnetic induction creates electricity from a changing magnetic field

The phenomenon was discovered in 1831 by Michael Faraday when an electric current was induced in a wire wrapped around an iron ring after a second wrapped wire not connected to the first was connected or disconnected from a battery.

Most advanced touch screens rely on electrical charge in your skin

Capacitive touch screens store electrical charges in an electrostatic grid of tiny wires. When we touch the screen a tiny electrical charge is transferred from the screen to the finger to complete a circuit (since skin has positive and negative charges). This connection creates a voltage drop on that point of the screen. Cloth, however, doesn't conduct electricity, which is why humans can't wear thick gloves and operate their smartphones.

The world's largest lemon battery was made from nearly 3,000 lemons

By connecting lemons with a piece of zinc on one side and a piece of copper on the other, a team from the Royal Society of Chemistry created a fruit battery with a capacity of 2,307.8 volts.

Planeterrellas create artificial auroras that mimic the atmospheric displays of light by setting up an electric field between two metal balls in a jar filled with a small amount of air.

How are scientists turning deserts into farmland?

This article explores how engineers are using a liquid nanoclay solution to transform barren deserts into productive fruit farms, drawing inspiration from how clay particles carried by floodwaters in the Nile Delta used to improve the fertility of...

Fracking provides access to fossil fuel reserves locked in underground rock

Using a pressurized fluid mixture that is over 90% water, cracks are created in shale about 2 miles deep to release trapped oil and natural gas. The process uses an average of 3 to 6 million gallons of water per well, which can strain local water supplies.

The Southern Ocean's powerful circular current isolates organisms in its environment

The spiralling current churns up nutrients across the frigid waters, leading to the evolution of fantastical organisms, including century-old starfish and colossal squid, and unique adaptations, including the icefish's clear blood and organic antifreeze, over the past 30 million years.

Our bodies cool us down by sweating because water requires a significant amount of energy to change state from liquid to gas, making it an ideal medium for carrying thermal energy away from our bodies.

Watch the Panama Canal's lock system lift a ship 85 feet above sea level to cross between two oceans.

Named after Nikola Tesla, who pioneered alternating current power systems, the Tesla coil was the first device to wirelessly transmit electricity.

Simulate the build-up and discharge of static electricity with 'John Travoltage.'

The speed of electricity may refer to the movement of electrons, which is on the order of a fraction of a millimeter per second, or energy, which is near the speed of light.

The fish doorbell letting people help spawning fish

Utrecht, a city in central Netherlands, has implemented an innovative "fish doorbell" system at a river lock to assist migrating fish during their spring journey to spawning areas. This unique setup allows online viewers to participate in helping fish navigate through the locks. An underwater camera is installed at the Weerdsluis lock, streaming live video to a dedicated website, where viewers may press a digital button when they see a fish.

High-frequency sound waves have been used to brew espresso with room-temperature water and about one-fourth the energy of a traditional espresso machine, which relies on hot water and pressure.

Breaking down the challenges of alkaline environments and how extremophiles survive them

These areas are far less acidic than the interiors of most organisms' cells, and this imbalance draws protons that are needed for various metabolic processes, including energy production, out of cells. To counter these effects, some alkaliphiles have developed stronger proton regulation across their cellular membranes and proteins that drive these processes with greater stability amid such acidity imbalances.