OpenStem

@openstem · Joined Jul 2026

7420 public items8 groups

Note~266 words · 1 min

Measuring a Footprint You Can't See A carbon footprint totals up the greenhouse gases a person, household, product, or activity is responsible for, expressed as an equivalent amount of carbon dioxide (CO₂e) so that different gases — like me

Environmental

Environmental · L2 · Carbon Footprint

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Note~290 words · 1 min

Three Axes, No Single Winner Every energy source can be judged on cost (upfront and ongoing), emissions (greenhouse gases and pollution released across its lifecycle), and reliability (can it deliver power whenever it's needed, or only unde

Environmental

Environmental · L2 · Comparing Energy Sources

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Note~239 words · 1 min

Why Cities Run Hot Cities can be noticeably warmer than the rural land around them, sometimes by several degrees, especially at night — a pattern called the urban heat island effect. It comes down to how built surfaces handle sunlight and h

Environmental

Environmental · L2 · Urban Heat Island Effect

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Note~171 words · 1 min

What Happens to Rubbish? When you throw something away, it doesn't just disappear. Most rubbish is collected and taken to a landfill — a huge area of land where it is buried. How Long Does Rubbish Last? Composting: A Better Path for Food Sc

Environmental

Environmental · L1 · Litter, Landfills & Composting

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Note~150 words · 1 min

What Are Glaciers and Ice Caps? A glacier is a giant, slow-moving mass of ice that forms on land from packed-down snow. An ice cap is a thick dome of ice covering land, often near the North and South Poles. Together, glaciers and ice caps h

Environmental

Environmental · L1 · Glaciers & Ice Caps

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Note~112 words · 1 min

Slow Giants Mountains look like they have always been there, but every mountain range had to be built — usually over millions of years, by the slow-moving forces of Earth's crust. Three Ways Mountains Form How a Fold Mountain Forms This pus

Environmental

Environmental · L1 · Mountains: How They Form

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Note~137 words · 1 min

What Makes a Desert a Desert? A desert is not defined by heat — it is defined by dryness. Any place that receives very little rain or snow each year counts as a desert, whether it is scorching hot or freezing cold. How a Rain Shadow Desert

Environmental

Environmental · L1 · Deserts: Hot & Cold

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Note~291 words · 1 min

Water Hidden Beneath Our Feet Groundwater fills the tiny pore spaces of soil and cracks in rock beneath the surface — not open caverns, but a landscape more like a saturated sponge. The upper boundary of the fully saturated zone is called t

Environmental

Environmental · L2 · Groundwater & Aquifers

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Note~294 words · 1 min

What's Actually Driving Forest Loss Deforestation today is driven mainly by agricultural expansion — cattle ranching and crops like soy and oil palm together account for the largest share of forest cleared worldwide — followed by logging fo

Environmental

Environmental · L2 · Deforestation: Causes & Effects

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Note~140 words · 1 min

What Are Wetlands? A wetland is any land covered by shallow water for part or all of the year — marshes, swamps, and bogs are all types of wetland. They sit between dry land and deep water, and that in-between spot makes them some of the ri

Environmental

Environmental · L1 · Wetlands & Swamps

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Note~141 words · 1 min

Coral: An Animal, Not a Rock Coral looks like colorful rock, but it is actually built by tiny animals called polyps. Each polyp makes a hard, stony skeleton, and over hundreds of years, millions of these skeletons stack together to form a c

Environmental

Environmental · L1 · Coral Reefs

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Note~127 words · 1 min

Layers of the Ocean The ocean is not the same all the way down. As you go deeper, sunlight fades, temperature drops, and pressure builds — so scientists divide the ocean into layers, called zones, based on how much light reaches them. Going

Environmental

Environmental · L1 · Ocean Zones

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Note~138 words · 1 min

Why Do Animals Migrate? Migration is a long, regular journey animals make, usually with the seasons. Animals migrate mostly for three reasons — and often more than one at once. Famous Journeys One Butterfly's Journey Takes Many Generations

Environmental

Environmental · L1 · Animal Migration

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Note~274 words · 1 min

When One Big Habitat Becomes Many Small Ones Habitat fragmentation happens when roads, farmland, or development cut a once-continuous habitat into smaller, separated patches. The total amount of habitat might look similar on a map, but brea

Environmental

Environmental · L2 · Wildlife Corridors & Habitat Fragmentation

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Note~326 words · 2 min

A Fast-Growing Waste Stream E-waste — discarded phones, computers, TVs, and appliances — is one of the fastest-growing waste categories in the world, driven by falling electronics prices, rapidly changing technology, and devices often desig

Environmental

Environmental · L2 · Electronic Waste

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Note~316 words · 2 min

An Unequal Burden Environmental justice is the principle that everyone — regardless of race, income, or background — deserves equal protection from environmental hazards and equal access to a healthy environment. It's a response to a well-d

Environmental

Environmental · L2 · Environmental Justice

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Note~125 words · 1 min

Nature's Recyclers When a leaf falls or an animal dies, it does not just sit there forever. Decomposers — living things that break down dead material — get to work, turning it back into nutrients that new plants can use. The Underground Foo

Environmental

Environmental · L1 · Worms & Decomposers

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Note~157 words · 1 min

Why Save Energy? Most homes get electricity from power plants, and many of those plants burn fuels that release greenhouse gases into the air. Using less energy at home means less fuel needs to be burned — which is good for both your energy

Environmental

Environmental · L1 · Saving Energy at Home

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Note~126 words · 1 min

Why Every Drop Counts Earth looks like a water-covered planet, but almost all of that water is salty ocean water we cannot drink. Only a small slice is fresh water available in rivers, lakes, and underground — so using it wisely at home rea

Environmental

Environmental · L1 · Saving Water at Home

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Note~134 words · 1 min

Getting Around Cleanly Every trip we take — to school, to a friend's house, across town — can be made in different ways. Some of those ways release exhaust into the air, and some do not. Choosing a Cleaner Trip None of these choices need to

Environmental

Environmental · L1 · Clean Transportation

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Note~248 words · 1 min

Demand vs Supply, in One Shared Unit Ecological footprint measures the demand side: how much biologically productive land and water a population needs to produce what it consumes and absorb its waste. Biocapacity measures the supply side: h

Environmental

Environmental · L3 · Ecological Footprint & Biocapacity

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Note~244 words · 1 min

Two Related but Distinct Processes Bioaccumulation is the build-up of a substance within a single organism over its lifetime, occurring when uptake outpaces excretion. Biomagnification is the resulting rise in concentration at each successi

Environmental

Environmental · L3 · Bioaccumulation & Biomagnification

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Note~237 words · 1 min

Watching the Planet from Orbit Remote sensing — collecting data about Earth's surface without physical contact, usually via satellite — lets scientists monitor environmental change at a scale and consistency that ground surveys alone can't

Environmental

Environmental · L3 · Environmental Monitoring & Remote Sensing

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Note~124 words · 1 min

The Problem With 'Use Once, Throw Away' A single-use plastic item — a bag, a straw, a bottle — might only be held for a few minutes. But once it is made, that plastic can stick around in the environment for hundreds of years, because most p

Environmental

Environmental · L1 · Plastic Alternatives

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Note~137 words · 1 min

A Second Chance for Wild Animals Sometimes wild animals get hurt, sick, or lose their parents — often because of accidents with cars, litter, or bad weather. Wildlife rescue centers step in to give these animals expert care and a chance to

Environmental

Environmental · L1 · Wildlife Rescue & Rehabilitation

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Note~172 words · 1 min

What Is the Difference? Weather is what the atmosphere is doing right now or over the next few days — today's temperature, whether it is raining, how strong the wind is. Climate is the long-term pattern of weather in a place, measured over

Environmental

Environmental · L2 · Weather vs Climate

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Note~295 words · 1 min

Trophic Levels: Who Eats Whom Every ecosystem is organised into feeding levels called trophic levels. Energy enters at the bottom, from sunlight, and moves upward as organisms eat one another. Energy Flows One Way; Nutrients Recycle Energy

Environmental

Environmental · L2 · Ecosystems & Food Webs

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Note~262 words · 1 min

What Is Biodiversity? Biodiversity is short for 'biological diversity' — the total variety of life on Earth. It exists at three nested levels: genetic diversity within a species, species diversity within a habitat, and ecosystem diversity a

Environmental

Environmental · L2 · Biodiversity & Species Loss

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Note~323 words · 2 min

Solar: Turning Light Directly Into Current A solar photovoltaic (PV) cell is a thin slice of silicon treated so that one layer has a surplus of electrons and the other has a deficit. When a photon of sunlight strikes the silicon with enough

Environmental

Environmental · L2 · How Renewable Energy Systems Work

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Note~299 words · 1 min

Ancient Life, Compressed Into Fuel Fossil fuels are called that for a reason — they really are fossils, in a sense. Coal, oil, and natural gas all form from the buried remains of organisms that lived and died millions of years ago, transfor

Environmental

Environmental · L2 · Fossil Fuels & Nonrenewable Resources

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