It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us.
Science
How the natural world works, and how we find out.
68 passages
Science passages
When you finish a chapter, a new memory may still be fragile.
At many coasts, the sea rises and falls twice during a tidal day.
Rocks can change from one type into another over time.
Animals must find food to get energy, but green plants make their own.
The human brain contains roughly eighty-six billion nerve cells called neurons.
The water in a puddle today may have floated in a cloud last week and rushed down a river last year.
Earth stays warm enough for life partly because of gases in its atmosphere.
A star is not eternal; it is born, lives, and dies over spans that dwarf human history.
Sleep supports the body and brain.
A desert can go months, even years, without rain.
Fly across many time zones, and your body arrives before your inner clock does.
Sunlight looks white, but it is really a blend of many colors mixed together.
Density describes how much mass fits into a given volume.
When you feel a sudden chill or a wave of strong emotion, small bumps may rise on your skin.
The immune system protects the body against infection.
Drop a stone into water and it sinks.
Lightning produces both a flash and thunder.
The grey-green crust on an old stone wall may look like a plant.
Sleep looks like a pause, but the brain remains active.
An oak stump shows a pattern of rings.
An antibiotic can change which bacteria survive.
On a clear day, the sky overhead looks blue.
Reactions caused by cosmic rays in the atmosphere produce carbon-14, an unstable form of carbon.
A patient may report less pain after taking an inert tablet: one without the medicine's active ingredient.
Snow that falls on central Antarctica may remain instead of melting.
Water alone does not wash away oil.
Your body keeps its core temperature within a narrow range.
Turn a tap and water may arrive almost at once.
Water taken from a reservoir may need treatment before it is safe to drink.
Half of a water system runs the other way.
You cut an onion, and your eyes begin to sting.
Stand in the same place on a sunny morning and again near the middle of the day.
A popcorn kernel is a seed with a tough outer shell.
On many cold days, you can see a small white puff when you breathe out.
From 1889 until 2019, the kilogram was defined by the mass of a platinum-iridium cylinder kept near Paris.
Imagine a research team measuring a quantity for which a respected earlier result already exists.
Continents appear fixed on a map, yet Earth's outer shell is divided into moving tectonic plates.
Dip one corner of a paper towel into colored water, and the wet patch slowly rises.
An aurora can appear as a pale arc, a moving curtain, or rays across a dark sky.
Fill a cup carefully, and the water may rise slightly above the rim before spilling.
On a hot day, a distant road may appear to hold a shining pool.
The DNA molecules in a eukaryotic cell are extremely long relative to the nucleus that holds them.
Pluck a stretched string, and it vibrates back and forth.
A wing moving through air produces lift through shape, angle, speed, and airflow.
After a clear night, grass may sparkle with water even when no rain fell.
A long bridge changes size as its materials warm and cool.
An unglazed clay jar can cool the water inside it without a motor or a block of ice.
At a paper-repair table, a thin paste can join torn fibers without hiding the page under thick glue.
On a clear, calm night, a hollow at the foot of a slope may frost while trees higher up remain untouched.
Sandpaper feels rough because hard grains cover its surface.
Bend a metal paper clip once, and it usually keeps its new shape.
Michael Faraday entered science through a bookbinder’s shop rather than a university.
Two handheld radios can lose contact when a hill stands between them.
A bowl containing only ice and liquid water tends toward a balance near water's normal freezing point.
A few dry rice grains rest on a thin film stretched tightly across a bowl.
A square frame made from four hinged bars can lean sideways without changing the length of any bar.
Every second, enormous numbers of neutrinos pass through your body and continue through Earth.
After rain reaches dry ground, the air may carry an earthy smell called petrichor.
A lightning rod does not repel storms.
A compass needle is a small magnet that can turn freely.
A lunar eclipse occurs when Earth moves between the Sun and the full Moon.
A low-energy ball cannot cross a hill; it rolls back.
A snow crystal can begin when water vapor forms ice around a tiny particle in a cloud.
A growing tree uses atmospheric carbon to form new wood.
A thermos often has one container inside another.
Earth's axis is tilted relative to its path around the Sun.
Two clocks can begin together, take different journeys, and disagree when reunited.
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