General Science: 600+ Most Important Science Facts - Part 5 (Definitions)

Question 1. What is science?
Science is the study of nature and the physical world using a systematic approach based on observation and experiment (i.e. the scientific method).

Question 2. What does it mean to be scientific?
Scientific essentially means that it can be tested. The main idea driven home in science textbooks for non-scientists is that a statement is scientific if you can test it.

Question 3. What is a hypothesis?
A hypothesis is not a completely blind guess, but is educated in some way.

Question 4. What is the distinction between astronomy and astrology?
Astronomy applies the scientific method to study the universe. Astrology begins by assuming that the positions of heavenly bodies impact the lives of humans.

Question 5. What is botany?
Botany is the study of plants.

Question 6. What is organic chemistry?
Organic chemistry is the study of compounds that contain carbon.

Question 7. What is anatomy?
Anatomy is the study of an organism’s body.

Question 8. What is ecology?
Ecology is the study of the relationship between organisms and their environment.

Question 9. What is a control group in medical science or psychology?
In medical science or psychology, a control group does not receive the treatment.

Question 10. What is the distinction between a dependent and an independent variable?
The independent variable is the factor that is manipulated during an experiment. The dependent variable changes in response to this manipulation.

Question 11. How does science define living things (that is, organisms)?
Living things (or organisms) respond to stimuli, grow and develop, consume energy, use resources, reproduce, and are based on a basic building block (a cell).

Question 12. What is a meniscus?
A meniscus refers to the curved upper surface of a liquid in a container.

Question 13. What is the current classification of Pluto? (Bonus if you can explain why.)
Pluto is a dwarf planet, largely because it hasn’t cleared matter from its orbit.

Question 14. What is an element?
An element can’t be broken down to a simpler structure using chemical means. The elements are different types of atoms.

Question 15. What is a compound?
A compound consists of two or more elements bound together in a definite proportion.

Question 16. What is a solution? What is a solute? What is a solvent?
A solution is a homogeneous mixture of two or more substances. One substance (the solute) is dissolved in another (the solvent) to form the solution.

Question 17. What is a homogeneous mixture? What is a heterogeneous mixture?
A homogenous mixture has a uniform distribution, unlike heterogeneous.

Question 18. What is an autotroph? What is a heterotroph?
An autotroph produces its own food (like plants and certain types of bacteria). A heterotroph gets its food from other organisms (plants or animals).

Question 19. What is a decomposer?
A decomposer breaks down an organism that is dead or decomposing.

Question 20. What is a barometer? What is a manometer?
A barometer measures atmospheric pressure. A manometer measures the pressure of a fluid (which may or may not be the atmosphere).

Question 21. What is the distinction between psychology and psychiatry?
Psychology is the study of behavior and the mind. Psychiatry is a branch of medical science that studies psychological disorders and is practiced by physicians.

Question 22. What is alchemy?
Alchemy was an early form of chemistry attempting to turn metals into gold.

Question 23. What is metallurgy?
Metallurgy is the branch of science that studies metals, including their purification (separation from ores) and production (for example, making alloys).

Question 24. What is the distinction between a metal and a nonmetal?
Metals tend to have a luster, be malleable, be ductile, be opaque, and be good conductors of both electricity and heat, unlike nonmetals.

Question 25. What are (at least) two different meanings of membrane in science?
A membrane could be a thin, flexible material serving as a filter (for example, in osmosis), it could be the thin structure that surrounds a cell (a cell membrane), or it could be a thin layer of cells that serves as a lining in a plant or animal.

Question 26. What is cartilage?
Cartilage is a firm, yet flexible connective tissue found (for example) in joints.

Question 27. What is bacteria? What is a virus?
Bacteria are unicellular prokaryotes with cell walls that contain peptidoglycan, which can survive in many different types of environments. A virus is a structure that is smaller than bacteria, consisting of protons and nucleic acids (and sometimes lipids), which generally needs a host (plant or animal). Antibiotics may kill bacteria, but aren’t effective against a virus.

Question 28. What is a catalyst?
A catalyst is a substance that affects the rate of a reaction (usually by speeding it up) without undergoing a (permanent) chemical change.

Question 29. What is density?
Density is mass per unit volume, which provides a measure of compactness.

Question 30. What is a mole?
A mole is a collection of entities equal to Avogadro’s number, 6.022 × 1023.

Question 31. What is a tissue? What is an organ?
Tissue consists of similar cells performing a similar function. An organ consists of tissues working together to perform functions that are closely related.

Question 32. What is an artery? What is a vein?
An artery is a large blood vessel in which blood travels away from the heart. A vein is a large blood vessel in which blood returns to the heart.

Question 33. How is soil defined in geology?
Soil is the surface layer of the earth that supports plant life, and which consists of minerals, organic matter, water, and air.

Question 34. How do you determine the slope of a graph?
The slope of a graph equals the rise divided by the run.

Question 35. What are first-, second-, and third-degree burns?
A first-degree burn involves reddening of the skin, a second-degree burn also has blisters, and a third-degree burn destroys skin and affects deeper tissues.

Question 36. What is a vector? What is a scalar?
A vector includes both a magnitude and direction. A scalar has a magnitude, but not direction. (The more technical distinction involves a coordinate transformation.)

Question 37. What is speed? What is velocity?
Speed is a measure of how fast an object moves (the instantaneous time rate of change of position). Velocity is a combination of speed and direction.

Question 38. What is acceleration?
Acceleration is a measure of how velocity changes (the instantaneous time rate of change of velocity), including changes in speed and changes in direction.

Question 39. What is the concentration of a solution?
Concentration is the amount of solute present in a given amount of solvent or solution. There are different forms of concentration, such as molarity and molality.

Question 40. What does it mean for a substance to be malleable?
Malleable means that a substance can change shape by hammering (for example) without breaking.

Question 41. What is the distinction between rotation and revolution in astronomy?
Rotation occurs when a body spins on its axis (like the earth completing one rotation on its axis every 24 hours), whereas revolution refers to a body that travels in an orbit (like the earth completing one revolution around the sun every 365 days).

Question 42. What is atomic number?
Atomic number refers to the number of protons in the nucleus of an atom.

Question 43. What is an era? What is an epoch? What is a period? What is an eon?
An eon is the longest unit of geologic time, followed by an era, a period, and an epoch. Bonus if you know how it is based on rock strata.

Question 44. What is a protein?
A protein is complex polymer consisting of long chains of amino acids, which is found in cells and which is an essential part of animals’ diets.

Question 45. What are convex and concave lenses? (Which is which?)
A convex lens curves outward in the middle and causes parallel rays of light to converge at a focus. A concave lens is narrower in its middle region and causes parallel rays of light to diverge away from a focus.

Question 46. What is an esophagus?
An esophagus is a tube extending from the mouth to the stomach.

Question 47. What is an endothermic reaction? What is an exothermic reaction?
An endothermic reaction absorbs energy. An exothermic reaction releases it.

Question 48. What is the distinction between a meteor, a meteorite, and a meteoroid?
A chunk of rock smaller than an asteroid is called a meteoroid out in space, a meteor as it burns while passing through the atmosphere, and a meteorite after it lands on the surface of a planet or moon.

Question 49. What is the distinction between neurosis and psychosis?
Neurosis is a mental disorder where a symptom causes psychological pain, and psychosis is a mental disorder where reality is distorted, such as through irrational thoughts, delusions, or hallucinations.

Question 50. What is a half-life?
Half-life is the time it takes for one-half of a sample to decay.

Question 51. What is a light-year?
One light-year is the distance (not a time) that light travels in one year.

Question 52. What is an astronomical unit (AU)?
One astronomical unit (AU) equals the average earth-sun distance.

Question 53. What does the triple point of a substance refer to?
Triple point (of a substance) refers to the combination of pressure and temperature for which the solid, liquid, and gaseous phases coexist in equilibrium.

Question 54. What is a neuron?
A neuron is a nerve cell.

Question 55. When is there a normal force? In which direction is it exerted?
When an object is in contact with a surface, the surface exerts a normal force on the object which is perpendicular to the surface.

Question 56. What is evolution? (This is asking for a definition, not your opinion.)
Evolution is the process by which, according to modern scientists, organisms have descended from previous organisms.

Question 57. What is a comet?
A comet is a body (typically icy) that orbits the sun in a highly elliptical orbit, and which develops a coma and tail when passing near enough to the sun.

Question 58. What is a larva? What is a pupa?
In the metamorphosis of an insect, the larva is the juvenile form and the pupa is the form it takes between the larva and adult forms.

Question 59. What is an isotope?
Two isotopes of the same element differ in the number of neutrons.

Question 60. What is an ion? What is ionization?
An ion is an atom that has more or fewer electrons than protons, and thus has a net charge. Ionization is the process by which an ion is formed.

Question 61. What is humidity? What is the dew point?
Humidity provides a measure of how much water vapor is in the air. The dew point is the temperature below which dew can form.

Question 62. What is current?
Current is the rate of flow of charge.

Question 63. What is an allele?
An allele is one of two (or more) forms of a gene located at the same position on a chromosome.

Question 64. What is an asteroid?
An asteroid is a rocky body that orbits a star, which is smaller than a planet, but larger than a meteoroid.

Question 65. What is a gamete?
A gamete is a reproductive cell.

Question 66. What is a noble gas?
A noble gas (or inert gas) is a highly unreactive element with a full valence shell.

Question 67. What is a halogen?
A halogen is a highly reactive element needing one electron to fill its valence shell.

Question 68. What is an orbital?
An orbital refers to the allowed energy state of an electron in an atom based on its principal, orbital, and magnetic quantum numbers.

Question 69. What is the distinction between diagnosis and prognosis?
Diagnosis refers to identifying a condition, disease, or disorder. Prognosis is a prediction for how it will develop and the outcome after treatment is given.

Question 70. What is the distinction between stress and strain?
Stress is an exerted force per cross-sectional unit of area. Strain is a measure of the degree to which an object deforms as a result of the stress.

Question 71. What is hemoglobin?
Hemoglobin is the protein in red blood cells which transports oxygen.

Question 72. What is a genome?
A genome is all of the genetic information found in the DNA of an organism.

Question 73. What does it mean for an object to be submerged?
An object is submerged when it is placed below the surface of a liquid.

Question 74. What do benign and malignant mean in medical science?
Benign is non-cancerous, while malignant is cancerous.

Question 75. What is a transistor?
A transistor is a semiconductor device that can act as a switch or an amplifier.

Question 76. What is leukemia?
Leukemia refers to cancer of blood-forming cells and tissues, including bone marrow.

Question 77. What is a polar molecule?
A polar molecule has a dipole moment; it can be divided (by an imaginary line) in such a way as to be positive on one side and negative on the other side.

Question 78. What is a lesion in medical science?
A lesion refers to an injury or an abnormal change in tissue.

Question 79. What is torque?
Torque equals force times lever arm and causes a rigid body to develop angular acceleration.

Question 80. What is a free radical?
A free radical has one or more unpaired electrons.

Question 81. What is a capacitor? (Indicate both what it does and what it consists of.)
A capacitor is a device that stores charge, consisting of two separated conductors.

Question 82. What is an antigen? What is an antibody?
An antigen is a toxin or potentially harmful substance that triggers an immune response from the body, which entails producing an antibody to neutralize it.

Question 83. What does acute mean regarding symptoms or illness?
Acute means abrupt onset and severe. For a symptom like pain, the duration is usually short. For a disease, it may also mean rapidly progressing.

Question 84. What is a biome?
A biome is a group of ecosystems that share similar climates and have organisms with similar characteristics.

Question 85. What is ozone? What is the ozone layer?
Ozone is the O3 allotrope of oxygen. (The most common allotrope, O2, forms at STP). The ozone layer is a layer of the stratosphere with a high concentration of ozone. It absorbs dangerous UV radiation from the sun.

Question 86. What does the term aqueous refer to?
Aqueous refers to a solution where the solvent is water.

Question 87. What is an abdomen?
In vertebrates, the abdomen lies between the thorax and pelvis, containing the digestive organs (and more), and is also known as the belly. In arthropods, the abdomen lies at the posterior, and contains reproductive organs (and more).

Question 88. What is an electrolyte?
An electrolyte is a solute which produces ions in a solution.

Question 89. What do the terms heterozygous and homozygous mean?
Heterozygous refers to a plant or animal with two different alleles located at the same position on a chromosome. For homozygous, the alleles are the same.

Question 90. What is nuclear fission? What is nuclear fusion?
Fission is a nuclear reaction where one nucleus splits into smaller nuclei. Fusion is a nuclear reaction where smaller nuclei are joined to form a heavier nucleus.

Question 91. What is an organelle?
An organelle is a discrete cell structure that has a specialized function.

Question 92. What is wavelength? What is period? What is frequency?
Wavelength is the distance that a wave travels in one cycle. Period is the time it takes to complete one oscillation. Frequency is the number of cycles per unit time.

Question 93. What is an equinox in astronomy? What are the two kinds?
An equinox refers to the two days of the year when the sun is at a position along the ecliptic that intersects the celestial equator, causing the day and night to be approximately equal in length. (Day and night aren’t exactly equal on these two days due to atmospheric refraction and the finite size of the sun.) Vernal and autumnal are the two types of equinoxes.

Question 94. What is a carbohydrate?
A carbohydrate is a type of organic compound that typically has a chemical formula of the form Cm(H2O)n, where m and n are integers, and is a major nutrient in animal diets.

Question 95. What is cytoplasm?
Cytoplasm refers to the protoplasm of a cell, excluding the nucleus (if it has one).

Question 96. What are ribosomes?
Ribosomes are cell organelles – present throughout the cytoplasm of a cell – consisting of RNA and proteins, where proteins are synthesized.

Question 97. What is the distinction between boiling and evaporation?
Boiling is a phase transition from liquid to gas. In evaporation, the fastest molecules escape from the liquid in vapor form without a phase change. Boiling occurs at the boiling point, whereas evaporation occurs even at temperatures much lower than the boiling point. Boiling occurs throughout the volume, whereas evaporation occurs at the surface of the liquid.

Question 98. What is a nebula?
A nebula is an interstellar region consisting of dust or gas.

Question 99. What is a pathogen?
A pathogen is a disease-carrying agent, perhaps in the form of a microorganism.

Question 100. What is energy? What are kinetic and potential energy? What is activation energy?
Energy represents the ability to do work. Kinetic energy is work that can be done by changing speed. Potential energy is work that can be done by changing position. Activation energy is the energy needed for a reaction to occur.

Question 101. What is entropy?
Entropy provides a measure of the statistical disorder of the molecules of a substance.

Question 102. What is enthalpy?
The enthalpy of a system equals internal energy plus pressure times volume, where PV may be thought of as energy stored in the surroundings. For a reaction that occurs at constant pressure, the change in enthalpy equals the heat exchanged.

Question 103. What is niacin?
Niacin, also known as vitamin B3, is an essential vitamin in many common foods that helps humans keep their nervous system, digestive system, and skin healthy.

Question 104. What is a delta in geology?
In geology, a delta refers to the sediment that accumulates (often in the shape of a triangle) where the mouth of a river meets a large body of water.

Question 105. What is a buffer in chemistry?
A buffer is an aqueous solution that can neutralize an acid or base added in a small amount (such that the pH level doesn’t change appreciably).

Question 106. What is a confounding variable?
A confounding variable is a factor other than the independent variable being manipulated which may affect the outcome of an experiment.

Question 107. What is a black hole?
A black hole is a celestial object (such as a collapsed star) with so much mass that its gravitational field prevents even light from escaping.

Question 108. What is a lattice in chemistry?
A lattice is a three-dimensional array of atoms (or groups of atoms).

Question 109. What is pressure? What is buoyancy?
Pressure is force per unit area. For a fluid, this is equivalent to density times gravitational acceleration times depth. Buoyancy refers to the net upward pressure (which results in a buoyant force) exerted on an object submerged in a fluid (as a result of greater upward pressure at the bottom of the object compared to smaller downward pressure at the top of the object, due to variation of pressure with depth).

Question 110. What is solubility?
Solubility at a given temperature is the amount of solute needed to dissolve in a given amount of solvent in order for the solution to be saturated.

Question 111. What is a tendon?
A tendon is tough connective tissue joining skeletal muscles to bones.

Question 112. What is a clavicle?
A clavicle is the collarbone.

Question 113. What are linear momentum and angular momentum?
Linear momentum, also called momentum, equals mass times velocity. Angular momentum is an analogous form of momentum for a rotating object, which equals moment of inertia times angular velocity.

Question 114. What is cellulose?
Cellulose is the main constituent of the walls of plant cells

Question 115. What is excretion?
Excretion is the process by which an organism eliminates metabolic wastes.

Question 116. What is oncology?
Oncology is the branch of medicine that studies the diagnosis and treatment of cancer.

Question 117. What is refraction?
Refraction refers to the bending of a ray of light as it passes from one medium to another medium (in which light travels a different speed).

Question 118. What is diffraction?
Diffraction refers to the bending of light around an obstacle, such as when it passes through a narrow slit (or through a grating).

Question 119. What is dispersion?
Dispersion refers to the separation of light into its constituent colors.

Question 120. What is kinesthesis?
Kinesthesis is the system for sensing the position, orientation, movement, etc. of the different parts of the body.

Question 121. What is chlorophyll?
Chlorophyll is the green pigment found in plant cells, and is essential for photosynthesis.

Question 122. What is a subduction zone?
A subduction zone refers to the sinking of one lithospheric plate under another when two lithospheric plates collide.

Question 123. What is an umbra? What is a penumbra?
The umbra is the portion of the shadow of an eclipse where sunlight can’t be seen. The penumbra is the portion of the shadow of an eclipse where sunlight shows partially. (Alternatively, these terms may also be used to describe sunspots.)

Question 124. What are the dermis and epidermis (in humans)?
The epidermis is the outer layer of the skin. The dermis lies beneath it.

Question 125. What is right ascension? What is declination?
Right ascension is celestial longitude. Declination is celestial latitude.

Question 126. What is a contusion in health science?
In health science, a contusion is a more technical term for bruise.

Question 127. What are glacial striations?
Glacial striations are grooves and scratches that form during glacial abrasion.

Question 128. What is a dielectric?
A dielectric is a non-conducting material that can sustain an electric field. A capacitor can store more charge when it includes a dielectric between its plates.

Question 129. What is beta carotene?
Beta carotene is a reddish-orange pigment found in many fruits and vegetables, which the human body converts into vitamin A.

Question 130. What is a fungus?
Fungi, which include mold, mildew, mushrooms, and yeast, usually have chitin in their cell walls, are usually immobile, are often parasites, and often feed by decomposing organic matter.

Question 131. What is isotropy?
Isotropy refers to a property that is the same in all directions.

Question 132. What is glucose?
Glucose has the chemical formula C6H12O6 and is the main sugar found in blood.

Question 133. What is a basin in geology?
In geology, a basin is a wide, rounded depression in which the rock layers incline toward a spot near the center.

Question 134. What is action potential?
Action potential is a neural impulse.

Question 135. What does it mean to be in remission in health science?
Remission is when the symptoms of a disease disappear or lessen.

Question 136. What do the terms aerobic and anaerobic mean in biology?
A process that requires oxygen is aerobic, whereas a process that does not require oxygen is anaerobic.

Question 137. What is aerobic exercise?
Aerobic exercise increases the efficiency with which the body takes in oxygen, increasing the fitness of the heart and lungs.

Question 138. What is the distinction between elastic, inelastic, and perfectly inelastic collisions?
A macroscopic collision is elastic if mechanical energy is conserved, inelastic if mechanical energy isn’t conserved, and perfectly inelastic if the objects stick together. (A collision between two point-like particles is elastic if identical particles appear in both the initial and final states, and is inelastic otherwise; for a collision between point-like particles, energy is conserved by the system.) Note that the law of conservation of momentum may apply regardless of whether a collision is elastic.

Question 139. What are longitudinal and transverse waves?
In a longitudinal wave, the amplitude of oscillation is aligned with the direction of propagation. In a transverse wave, the amplitude of oscillation is perpendicular to the direction of propagation.

Question 140. What is resonance?
Resonance is the phenomenon where the frequency is just right such that the reflected waves create a standing wave with a much larger amplitude than any of the individual waves.

Question 141. What is a larynx?
Larynx is the technical term for voice box.

Question 142. What is the Kuiper Belt? What is the Oort Cloud?
The Kuiper Belt is a large belt of icy bodies in the outer solar system, which is the source of many comets and some dwarf planets like Pluto. The Oort Cloud is a vast spherical shell extending beyond the Kuiper Belt, which also contains icy bodies.

Question 143. What is a tumor?
A tumor is an abnormal mass of tissue growth. It is not necessarily cancerous.

Question 144. What is a calorimeter?
A calorimeter is a device that measures the amount of heat exchanged. A simple calorimeter consists of a container of liquid with a thermometer, to which another substance (of different temperature than the liquid) may be added.

Question 145. What is agriculture?
Agriculture is the branch of science that studies farming.

Question 146. What is a colloid in chemistry?
A colloid is a mixture where particles dispersed throughout remain suspended in the medium. (The term may refer to such particles or to the entire mixture.)

Question 147. What is a shock wave?
A shock wave results when an object travels faster than the speed of the waves it produces in a medium. Examples include V-shaped waves that ducks and boats create in water and the sonic boom created by supersonic aircraft.

Question 148. What is pneumonia?
Pneumonia refers to an infection that inflames the alveoli of the lungs.

Question 149. What are strata in geology?
In geology, strata are layers of sedimentary rock.

Question 150. What is a quark? Which flavors can you name?
A quark is a subatomic particle with fractional charge always found in groups of two or three. They make up baryons (like the proton and neutron) and mesons (like the pion and kaon). The six flavors include up, down, charm, strange, top, and bottom (not to be confused with colors, which are red, green, and blue).

Question 151. What are mitochondria?
Mitochondria are cell organelles that generate ATP (a source of chemical energy).

Question 152. What is a photon?
A photon is a single particle of light corresponding to one quantum of energy.

Question 153. Which specific particles are released in alpha, beta, and gamma decays?
A helium nucleus is released during alpha decay, an electron or positron is released during beta decay, and a photon is released during gamma decay.

Question 154. What is the distinction between an acid and a base? (Don’t use the pH scale to explain.)
An acid is a substance that increases the concentration of H+ (aq) when it dissolves in water. A base is a substance that increases the concentration of OH– (aq) when it dissolves in water.

Question 155. What is glaucoma?
Glaucoma is a group of eye conditions featuring increased pressure and nerve damage, which can lead to blindness.

Question 156. What is melanin?
Melanin is a dark brown pigment in skin that absorbs UV rays.

Question 157. What is cryogenics?
Cryogenics is the branch of science that studies low-temperature physics.

Question 158. What is a crystalline solid?
A crystalline solid features a regular geometric arrangement of its molecules, atoms, or ions.

Question 159. What is an amorphous solid?
An amorphous solid lacks the regular geometric pattern of crystalline solids.

Question 160. What is a chloroplast?
Chloroplast is a cell organelle in plants and green algae where photosynthesis occurs.

Question 161. What are eukaryotes and prokaryotes?
Eukaryotes are organisms with cells that contain a nucleus and prokaryotes are unicellular organisms (such as bacteria) with cells that don’t contain a nucleus.

Question 162. What is an aperture?
An aperture is a small opening (or its diameter) through which light enters to pass through the lens of a camera, telescope, or other optical instrument.

Question 163. What are hyperglycemia and hypoglycemia?
Hyperglycemia is abnormally high blood sugar and hypoglycemia is abnormally low blood sugar (in terms of concentration).

Question 164. What is oxidation? What is reduction?
Oxidation is a reaction where a substance loses electrons. Reduction is a reaction where a substance gains electrons. (Since an electron is negative, its charge is reduced.)

Question 165. What is a cation? What is an anion?
A cation is an ion with positive charge. An anion is an ion with negative charge.

Question 166. What are a cathode and anode in electrochemistry?
A cathode is an electrode where reduction occurs. An anode is an electrode where oxidation occurs.

Question 167. What is basalt?
Basalt is a dark, fine-grained igneous rock that is rich in magnesium and iron, and is low in silica content.

Question 168. What are the adrenal glands? What is their function?
Adrenal glands are a pair of endocrine organs above the kidney. They secrete hormones that help with metabolism, immunity, stress, etc.

Question 169. What is a positron?
A positron is the antiparticle of the electron. It has the same mass as an electron, but is positively charged.

Question 170. What is an estuary?
An estuary is a wetland that forms where a river meets an ocean.

Question 171. What is a cornea?
The cornea is the tough transparent tissue that covers the iris and pupil of the eye.

Question 172. What is a cochlea?
The cochlea is the spiraling part of the inner ear where sound is detected.

Question 173. What are biotic and abiotic factors?
Biotic factors refer to living (or previously living) elements and abiotic factors refer to non-living elements.

Question 174. What is autism?
Autism is a disorder characterized by communication difficulties and impaired social interaction, which appears during childhood.

Question 175. What are a stalactite and a stalagmite? Which is which?
A stalactite (think “t” for top or “c” for ceiling) is a mineral deposit resembling an icicle which hangs from the roof of a cave. A stalagmite (think “g” for ground) is a cone-shaped mineral deposit rising up from the floor of a cave.