Anatomy
Responsible for your pulse, this organ is the only muscle in the human body that continuously works without ever getting tired or needing a rest break.
What is the heart?
Added to baking recipes to make dough rise, this common household compound releases bubbles of carbon dioxide gas when it reacts with acidic ingredients like vinegar or buttermilk.
What is baking soda (or sodium bicarbonate)?
Found inside plant cells, this green pigment absorbs sunlight to convert water and carbon dioxide into sugar during photosynthesis.
What is chlorophyll?
Formed over millions of years by flowing water, this massive landmark in Arizona carved out by the Colorado River exposes nearly two billion years of Earth's geological history.
What is the Grand Canyon?
Because its atmosphere traps solar heat under a thick layer of carbon dioxide clouds, this second planet from the Sun holds the record as the hottest planet in our solar system.
What is Venus?
Despite being known as your "funny bone," hitting this spot on your elbow actually compresses a nerve rather than a bone.
What is the ulnar nerve (accept "funny bone" / nerve)?
Essential for fire, this abundant gas makes up roughly 21% of Earth's atmosphere and is the key element required for any standard combustion reaction to occur.
What is oxygen?
While humans have 23 pairs of these thread-like structures carrying genetic information in every cell, chimpanzees have 24.
What are chromosomes?
Measuring a 7.0 or higher on the Moment Magnitude scale, these geological events occur when stress along subterranean fault lines suddenly releases seismic waves through the crust.
What is an earthquake?
Occurring when the Moon passes directly between the Earth and the Sun, this celestial event temporarily casts a shadow over Earth and blocks out daytime sunlight.
What is a solar eclipse?
Because it produces pigments to shield your deeper skin layers from ultraviolet light damage, exposure to the sun causes this largest organ of the body to darken into a tan.
What is the skin?
Formed when iron reacts with oxygen and moisture over time, this reddish-brown flakey compound is the visual result of metallic oxidation.
What is rust (or iron oxide)?
Unlike warm-blooded mammals that regulate their own temperature internally, reptiles are classified as this, needing external heat sources like sunlit rocks to warm up.
What is cold-blooded (or ectothermic)?
Driven by heat from Earth's core, this continuous circular movement of molten rock in the mantle acts as the primary engine pushing tectonic plates across the globe.
What are convection currents?
Although commonly referred to as "shooting stars," these bright streaks of light across the night sky are actually tiny bits of space dust or rock burning up in Earth's atmosphere.
What are meteors (or shooting stars / meteorites)?
Resembling a pair of wings framing your upper back, these triangular flat bones are commonly called the shoulder blades.
What are the scapulae (or shoulder blades)?
Measuring from 0 to 14, this logarithmic scale tells you how acidic or basic an aqueous solution is, with 7 representing pure neutral water.
What is the pH scale?
This biological phenomenon occurs when two different organisms live together in a close relationship that benefits both species, such as clownfish hiding inside sea anemones.
What is mutualism (or symbiosis)?
Occurring when charged solar particles collide with gases in Earth's upper atmosphere, this dazzling atmospheric light show is most visible near the North Pole.
What are the Northern Lights (or Aurora Borealis)?
Taking about 230 million Earth years to complete a single orbit around the center of the Milky Way, this star sits at the very center of our solar system.
What is the Sun?
Connected to your calf, this thick structure behind your ankle is the strongest tendon in the human body, named after a famous mythical Greek warrior's single physical weakness.
What is the Achilles tendon?
Named after the glowing property it exhibits, this element glows in the dark when exposed to oxygen and is famous for making up the structural framework of human bones and teeth.
What is phosphorus?
Acting as the biological clock of the body, this 24-hour cycle dictates sleep patterns, alertness, and hormone release based on natural light and darkness.
What is the circadian rhythm?
Ringing the basin of the Pacific Ocean, this 25,000-mile horseshoe-shaped belt is home to over 75% of the planet's active and dormant volcanoes.
What is the Ring of Fire?
Named because its gravitational pull is so immensely strong that not even light can escape it, this region of space forms when a massive star collapses in on itself.
What is a black hole?