Transpiration drives water movement through a plant’s vascular system

How trees transport water from roots to leaves

Trees move water to their extremities via a deft system starting from the roots to the leaves. See how it works in this short video breaking down the process in a Douglas fir.

From evaporation to precipitation: An overview of the water cycle

The water cycle is a natural process that continuously circulates water throughout Earth's systems. View this diagram from NASA to understand how the water cycle incorporates evaporation, condensation, precipitation, and more. First, the sun's heat...

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.

Visualize the purpose of stomata in photosynthesis

These openings on the underside of leaves can be opened and closed by specialized guard cells to regulate the movement of carbon dioxide into and oxygen out of cells, thus impacting the rate of photosynthesis. At night, when the light-dependent reactions in photosynthesis are not possible, the stomata close to prevent the plant from losing water through transpiration.

Explaining how water's movement between different salt concentrations can generate electricity

Water naturally moves from regions of low salinity, such as freshwater, to regions of high salinity, such as ocean water, across a semipermeable membrane. This movement produces pressure that can be harnessed in osmotic power systems to drive turbines and generate electricity, much like in hydroelectric plants.

View colorful flowers that grow on cacti and succulents, popular xerophilic organisms

These dry-loving organisms are able to retain the water they need to grow and reproduce in deserts and arid grasslands through a suite of adaptations, including thick, fleshy stems that store abundant water, a waxy coating that helps prevent water loss, and an uncommon form of photosynthesis that loses less water.

Oxygen and nutrients are circulated in tardigrade bodies through physical movement

Rather than having a circulatory system, oxygen is directly absorbed through their skin and spreads through a fluid called hemolymph as tardigrades crawl. When molting to grow, they shed their outer skin and stylets—sharp mouth parts used to pierce prey—which are regrown in their salivary glands.

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.

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.

Atmospheric rivers are the largest freshwater transport mechanism on Earth

Serving as highways that carry the water vapor equivalent of up to 15 times the average flow of water at the mouth of the Mississippi River, atmospheric rivers are approximately 400 to 600 kilometers (250 to 375 miles) wide and provide 30-50% of the annual precipitation of the US West Coast.

Some tectonic plates move faster than their underlying convection currents

Like a chain slipping off a ledge, as tectonic plates sink, their weight can pull the rest of the trailing plate forward, accelerating their movement. Plates can also break apart and fall, creating a suction effect that drives movement, resembling leaves following a passing car.

Watch students comically portray how plants can detoxify the environment

Through a series of processes that collectively make up phytoremediation, plants can take up pollutants from soil and water through their roots, then break them down, release them as less harmful gases, or store them within their cells. Any plants that sequester heavy metals or other toxins must be removed and managed after the environment is decontaminated.

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.

A Venus flytrap's hairs convert sensory touch into electrical signals

A stretch-activated ion channel called DmMSL10 acts as an amplifier, converting grazing contact into a strong impulse that the plant uses to react and close its jaw. To distinguish prey from raindrops or other stimuli, the jaw only closes when the hairs are touched twice in quick succession.

Programmed cell death drives leaves to fall from trees

All living things have innate mechanisms to prompt organized cell death, typically to protect the integrity of the living organism. Leaves fall from trees to allow the tree to preserve resources and bloom again in the future.

Blood leaves the heart at speeds around 12-16 miles per hour

Blood is pumped around the body through the circulatory system, aka the cardiovascular system. This system comprises the heart, arteries, veins, and capillaries. This video is the first in a multi-part series on the circulatory system, focusing on the role of the heart, the pump that powers the entire system.

An explanation of the Calvin cycle, including why it needs to run six times to create glucose

Each run of this second phase of photosynthesis begins with a five-carbon molecule called RuBP, which gains an additional carbon atom when carbon dioxide (CO₂) is attached. Across six cycles, the six six-carbon molecules—36 carbon atoms in total—are processed into 12 three-carbon sugars, which can be used to generate glucose, and six RuBP molecules, enough for each cycle to restart.

Pollinators help develop seeds by transferring pollen between flowering plants

As bees approach a bright, colorful flower for nectar, they bump into its stamen—the flower's male reproductive organ—and pollen gets stuck to the pollinator's body. This pollen can then be deposited on another flower's sticky pistil—the flower's female reproductive organ—which brings the pollen down to the ovule for fertilization.

Adhesion molecules and intercellular junctions allow cells to connect together

While some organic structures are mostly composed of non-cellular components (e.g., collagen and calcium phosphate minerals in bones), tissues and organs composed of connected cells rely on specialized proteins and connections to create watertight seals that protect cells within the interior from environmental molecules.

A fascinating look at why cucumber tendrils coil in opposite directions

The tendrils of cucumber plants coil when they hit a surface, creating a distinct telephone-cord look. Charles Darwin wrote about the mystery in the 1850s, though it wasn't until the 21st century that scientists figured out just how mysterious the coil is: its tendrils coil in opposite directions.

How the body produces urine

Things seem so simple when nature calls. But, how does the body actually produce the urine we so regularly and thoughtlessly expel? This detailed, comprehensive animation walks viewers through every step with precise illustrations, from the kidney's filters (known as nephrons) to the direct nerve connecting the bladder to the brain. See how the body does it here.

View the transition from laminar to turbulent flow

Using a dye released in the water, streamlines, which are parallel to one another and consistent at low flow velocities, become visible. As the water moves more quickly, viscosity cannot suppress the velocity change, and streamlines become chaotic, creating turbulence.

Humans need higher levels of water-soluble vitamins that easily pass through the body

There are two types of vitamins: lipid soluble and water-soluble. Water-soluble vitamins like B vitamins and vitamin C are in the watery parts of fruits and easily pass through the human body before being taken up by the bloodstream or exiting your body. But lipid (fat) soluble vitamins must be absorbed through the intestinal wall, carried by proteins, and then may be stored in the liver and other body parts—meaning there is greater risk of overdosing.

Solar wind may have contributed to Mars losing its atmosphere

Scientists believe that over hundreds of millions of years, energetic particles from the sun colliding with atmospheric particles, flinging them away from Mars' weak gravitational field like colliding billiard balls. As atmospheric pressure decline, water also evaporated away from the surface.

Tannins contribute to a wine's composition

Tannins are compounds found in many different types of food, including grape skins. When consumed, they produce a noticeable drying effect in the mouth. Because of the difference in production methods, red wines typically have tannins while white wines do not.

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

Explore the water footprint of producing various proteins, fruits, and vegetables

This interactive gallery highlights the various types of water behind the production of biofuels, foods, and materials such as cotton. Diets high in bovine meat, whose production requires 15,415 liters of water per kilogram (1,847 gallons per pound), are among the most water-intensive, whereas every kilogram of vegetables uses 322 liters of water (39 gal/lb) to produce.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

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.

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.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

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.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

Ebola infects and disables immune cells, triggering a cascade of events that leads to small blood clots throughout the body, weakening blood vessels and interrupting blood flow to key organs.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

Tattoos remain visible on your skin thanks to immune cells called macrophages

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.

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

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.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

Watch this video that uses Lego bricks to explain how venture capital works.

US consumers collectively owe more than $1T to credit card companies—almost as much as they owe in auto loans.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

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

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect