Water | Sleep Podcast For Insomnia

Still awake? Might as well spend a few minutes learning about the most important substance on Earth. In this episode, we take a slow, steady look at water and how it moves through the planet in a continuous cycle.

We’ll cover where water is found, how it changes between liquid, solid, and gas, and how processes like evaporation and precipitation keep everything in motion. It’s simple, foundational stuff, explained clearly and without rushing.

No whispering, no sudden noises, just a consistent, even delivery designed to help you fall asleep.

Happy sleeping!

Transcript

Welcome to the I Can't Sleep Podcast, Where I help you drift off one fact at a time. I'm your host, Benjamin Boster, And today's episode is about water. Water is an inorganic compound with the chemical formula H2O. It is a transparent, Tasteless, Odorless, And nearly colorless chemical substance. It is the main constituent of earth's streams, Lakes, And oceans, And the fluids of all known living organisms, In which it acts as a solvent. Water, Being a polar molecule, Undergoes strong intermolecular hydrogen bonding, Which is a large contributor to its physical and chemical properties. It is vital for all known forms of life, Despite not providing food, Energy, Or being an organic micronutrient. Due to its presence in all organisms, Its chemical stability, Its worldwide abundance, And its strong polarity relative to its small molecular size, Water is often referred to as the universal solvent. Because earth's surface temperature and pressure is relatively close to water's triple point, Water exists on earth as a solid, A liquid, And a gas. It forms precipitation in the form of rain, And aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, Its solid state. When finely divided, Crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water covers about 71% of the earth's surface, With seas and oceans making up most of the water volume, About 96. 5%. Small portions of water occur as groundwater, In the glaciers and the ice caps of Antarctica and Greenland, And in the air as vapor, Clouds consisting of ice and liquid water suspended in air, And precipitation. Water moves continually through the water's cycle of evaporation, Transpiration, Condensation, Precipitation, And runoff, Usually reaching the sea. One factor in estimating when water appeared on earth is that water is continually being lost to space. H2O molecules in the atmosphere are broken up by photolysis, And the resulting free hydrogen atoms can sometimes escape earth's gravitational pull. When the earth was younger and less massive, Water would have been lost to space more easily. Lighter elements like hydrogen and helium are expected to leak from the atmosphere continually, But isotopic ratios of heavier noble gases in the modern atmosphere suggest that even the heavier elements in the early atmosphere were subject to significant losses. In particular, Xenon is useful for calculations of water loss over time. Not only is it a noble gas, And therefore is not removed from the atmosphere through chemical reactions with other elements, But comparisons between the abundances of its nine stable isotopes in the modern atmosphere reveal that the earth lost at least one ocean of water, A volume of water approximately equal to modern ocean volume early in its history. This is likely to have occurred between the Hadean and Archean eons, In cataclysmic events such as the moon-forming impact. Any water on earth during the latter part of its accretion would have been disrupted by the moon-forming impact roughly 4. 5 billion years ago, Which likely vaporized much of earth's crust and upper mantle and created a rock vapor atmosphere around the young planet. The rock vapor would have condensed within 2, 000 years, Leaving behind hot volatiles which probably resulted in a majority carbon dioxide atmosphere with hydrogen and water vapor. Afterward, Liquid water oceans may have existed despite the surface temperature of 230 degrees Celsius due to the increased atmospheric pressure of the CO2 atmosphere. As the cooling continued, Most CO2 was removed from the atmosphere by subduction and dissolution in ocean water but levels oscillated wildly as new surface and mantle cycles appeared. Geological evidence also helps constrain the time frame for liquid water existing on earth. A sample of pilobosalt, A type of rock formed during an underwater eruption, Was recovered from the Isua Greenstone Belt and provides evidence that water existed on earth 3. 8 billion years ago. In the Navuogatuck Greenstone Belt, Quebec, Canada, Rocks dated at 3. 8 billion years old by one study and 4. 28 billion years old by another show evidence of the presence of water at these ages. If oceans existed earlier than this, Any geological evidence has yet to be discovered which may be because such potential evidence has been destroyed by geological processes like crustal recycling. More recently, In August 2020, Researchers reported that sufficient water to fill the oceans may have always been on the earth since the beginning of the planet's formation. Unlike rocks, Minerals called zircons are highly resistant to weathering and geological processes and so are used to understand conditions on the very early earth. Mineralogical evidence from zircons has shown that liquid water and an atmosphere must have existed 4. 404 ± 0. 008 billion years ago, Very soon after the formation of earth. This presents somewhat of a paradox as the cool early earth hypothesis suggests temperatures were cold enough to freeze water between about 4. 4 billion and 4 billion years ago. Other studies of zircons found in Australian, Haiti and rock point to the existence of plate tectonics as early as 4 billion years ago. If true, That implies that rather than a hot molten surface and an atmosphere full of carbon dioxide, Early earth's surface was much as it is today in terms of thermal insulation. The action of plate tectonics traps vast amounts of CO2, Thereby reducing greenhouse effects, Leading to a much lower surface temperature and the formation of solid rock and liquid water. Water, H2O, Is a polar inorganic compound. At room temperature it is a tasteless and odorless liquid, Nearly colorless, With a hint of blue. The simplest hydrogen chalcogenide, It is by far the most studied chemical compound and is sometimes described as the universal solvent for its ability to dissolve more substances than any other liquid, Though it is poor at dissolving non-polar substances. This allows it to be the solvent of life. Indeed, Water, As found in nature, Almost always includes various dissolved substances, And special steps are required to obtain chemically pure water. Water is the only common substance to exist as a solid, Liquid and gas in normal terrestrial conditions. Along with oxidane, Water is one of the two official names for the chemical compound H2O. It is also the liquid phase of H2O. The other two common states of matter of water are the solid phase, Which is ice, And the gaseous phase, Water vapor or steam. The addition or removal of heat can cause phase transitions, Freezing, Melting, Vaporization, Condensation, Sublimation and deposition. Water is one of only a few common naturally occurring substances, Which for some temperature ranges becomes less dense as they cool. It is the only known naturally occurring substance which does so while liquid. In addition, It is unusual because it becomes significantly less dense as it freezes, Though it is not unique in that respect. At 1 atm pressure, It reaches its maximum density of 999. 972 kg per m3 at 3. 98 °C. Below that temperature, But above the freezing point, Water expands, Becoming less dense. Until it reaches the freezing point, At which its density in the liquid phase is 999. 8 kg per m3. As water cools to 3. 98 °C, Water volume decreases. As it freezes and becomes ice, Water expands by about 9%, Reaching a density of 917 kg per m3. This expansion can exert enormous pressure, Bursting pipes and cracking rocks. As a solid, It displays the universal behavior of contracting and becoming more dense as it cools. These unusual thermal properties have important consequences for life on earth. In a lake or ocean, Water at 4 °C sinks to the bottom and ice forms on the surface, Floating on the liquid water. This ice insulates the water below, Preventing it from freezing solid. Without this protection, Most aquatic organisms residing in lakes would perish during the winter. In addition, This anomalous behavior is an important part of the thermohaline circulation, Which distributes heat around the planet's oceans. Water is a diamagnetic material. Though interaction is weak, With superconducting magnets it can attain a notable interaction. At a pressure of 1 atm, Ice melts or water freezes, Solidifies at 0 °C, And water boils or vapor condenses at 100 °C. However, Even below the boiling point, Water can change to vapor at its surface by evaporation. Sublimation and deposition also occur on surfaces. For example, Frost is deposited on cold surfaces, While snowflakes form by deposition on an aerosol particle or ice nucleus. In the process of freeze-drying, A food is frozen and then stored at low pressure, So the ice on its surface sublimates. The melting and boiling points depend on pressure. A good approximation for the rate of change of the melting temperature with pressure is given by the Clausius-Clapeyron relation. DT over dp equals T times the quantity V sub-L minus V sub-S, All over L sub-F, Where V sub-L and V sub-S are the molar volumes of the liquid and solid phases, And L sub-F is the molar latent heat of melting. In most substances, The volume increases when melting occurs, So the melting temperature increases with pressure. However, Because ice is less dense than water, The melting temperature decreases. In glaciers, Pressure melting can occur under sufficiently thick volumes of ice. Resulting in subglacial lakes. The Clausius-Clapeyron relation also applies to the boiling point, But with the liquid-gas transition, The vapor phase has a much lower density than the liquid phase, So the boiling point increases with pressure. Water can remain in a liquid state at high temperatures in the deep ocean or underground. For example, Temperatures exceed 205 degrees Celsius in Old Faithful, A geyser in Yellowstone National Park. In hydrothermal vents, The temperature can reach 400 degrees Celsius. At sea level, The boiling point of water is 100 degrees Celsius. As atmospheric pressure decreases with altitude, The boiling point decreases by 1 degree Celsius every 274 meters. High-altitude cooking takes longer than sea-level cooking. For example, At 1, 524 meters, Or 5, 000 feet, Cooking time must be increased by a fourth to achieve the desired result. Conversely, A pressure cooker can be used to decrease cooking times by raising the boiling temperature. In a vacuum, Water will boil at room temperature. On a pressure-temperature phase diagram, There are curves separating solid from vapor, Vapor from liquid, And liquid from solid. These meet at a single point called the triple point, Where all three phases can coexist. The triple point is at a temperature of 273. 16 Kelvin and a pressure of 611. 657 Pascals. It is the lowest pressure at which liquid water can exist. Until 2019, The triple point was used to define the Kelvin temperature scale. The water-vapor phase curve terminates at 647. 096 Kelvin and 22. 064 megapascals. This is known as the critical point. At higher temperatures and pressures, The liquid and vapor phases form a continuous phase called a supercritical fluid. It can be gradually compressed or expanded between gas-like and liquid-like densities. Its properties, Which are quite different from those of ambient water, Are sensitive to density. For example, For suitable pressures and temperatures, It can mix freely in non-polar compounds, Including most organic compounds. This makes it useful in a variety of applications, Including high-temperature electrochemistry and as an ecologically benign solvent or catalyst in chemical reactions involving organic compounds. In Earth's mantle, It acts as a solvent during mineral formation, Dissolution, And deposition. The normal form of ice on the surface of Earth is Ice I sub H, A phase that forms crystals with hexagonal symmetry. Another with cubic crystalline symmetry, Ice I sub C, Can occur in the upper atmosphere. As the pressure increases, Ice forms other crystal structures. As of 2024, 20 have been experimentally confirmed and several more are predicted theoretically. The 18th form of ice, Ice 18, A face-centered cubic superionic ice phase, Was discovered when a droplet of water was subject to a shock wave that raised the water's pressure to millions of atmospheres and its temperature to thousands of degrees, Resulting in a structure of rigid oxygen atoms in which hydrogen atoms flowed freely. When sandwiched between layers of graphene, Ice forms a square lattice. The details of the chemical nature of liquid water are not well understood. Some theories suggest that its unusual behavior is due to the existence of two liquid states. Pure water is usually described as tasteless and odorless, Although humans have specific sensors that can feel the presence of water in their mouths, And frogs are known to be able to smell it. However, Water from ordinary sources, Including mineral water, Usually has many dissolved substances that may give it varying tastes and odors. Humans and other animals have developed senses that enable them to evaluate the potability of water, To avoid water that is too salty or putrid. Pure water is visibly blue due to absorption of light in the region circa 600-800 nm. The color can be easily observed in a glass of tap water placed against a pure white background in daylight. The principal absorption bands responsible for the color are overtones of the OH stretching vibrations. The apparent intensity of the color increases with the depth of the water column, Following Beer's Law. This also applies, For example, With a swimming pool, When the light source is sunlight reflected from the pool's white tiles. In nature, The color may also be modified from blue to green, Due to the presence of suspended solids or algae. In industry, Near-infrared spectroscopy is used with aqueous solutions as the greater intensity of the lower overtones of water means that glass cuvettes with short pass lengths may be employed. To observe the fundamental stretching absorption spectrum of water, Or of an aqueous solution in the region around 3500 nm, A pass length of about 25 micropascals is needed. Also, The cuvette must be both transparent around 3500 nm and insoluble in water. Calcium fluoride is one material that is in common use for the cuvette windows with aqueous solutions. The Raman active fundamental vibrations may be observed with, For example, A 1 cm sample cell. Aquatic plants, Algae and other photosynthetic organisms can live in water up to hundreds of meters deep, Because sunlight can reach them. Practically no sunlight reaches the parts of the oceans below 1000 nm. The refractive index of liquid water is much higher than that of air, Similar to those of alkanes and ethanol, But lower than those of glycerol, Benzene, Carbon disulfide and common types of glass. The refraction index of ice is lower than that of liquid water. Hydrology is the study of the movement, Distribution and quality of water throughout the Earth. The study of the distribution of water is hydrography. The study of the distribution and movement of groundwater is hydrogeology. Of glaciers is glaciology. Of inland waters is limnology. And distribution of oceans is oceanography. Ecological processes with hydrology are in the focus of ecohydrology. The collective mass of water found on, Under and over the surface of a planet is called the hydrosphere. Earth's approximate water volume, The total water supply of the world, Is 1. 386 billion cubic kilometers. Liquid water is found in bodies of water, Such as an ocean, Sea, Lake, River, Stream, Canal, Pond or puddle. The majority of water on Earth is seawater. Water is also present in the atmosphere in solid, Liquid and vapor states. It also exists as groundwater in aquifers. Water is important in many geological processes. Groundwater is present in most rocks. And the pressure of this groundwater affects patterns of faulting. Water in the mantle is responsible for the melt that produces volcanoes at subduction zones. On the surface of the Earth, Water is important in both chemical and physical weathering processes. Water, And to a lesser but still significant extent ice, Are also responsible for a large amount of sediment transport that occurs on the surface of the Earth. Deposition of transported sediment forms many types of sedimentary rocks, Which make up the geological record of Earth history. The water cycle, Known scientifically as the hydrologic cycle, Is a continuous exchange of water within the hydrosphere, Between the atmosphere, Soil water, Surface water, Groundwater and plants. Water moves perpetually through each of these regions in the water cycle, Consisting of the following transfer processes. Evaporation from oceans and other water bodies into the air, And transpiration from land plants and animals into the air. Precipitation from water vapor condensing from the air and falling to the earth or ocean. Runoff from the land, Usually reaching the sea. Most water vapors, Found mostly in the ocean, Returns to it. But winds carry water vapor over the land at the same rate as runoff into the sea, About 47 teratons per year, While evaporation and transpiration happening in land masses also contribute about 72 teratons per year. Precipitation at a rate of 119 teratons per year over land has several forms. Most commonly rain, Snow and hail, With some contribution from fog and dew. Dew is small drops of water that are condensed when a high density of water vapor meets a cool surface. Dew usually forms in the morning when the temperature is the lowest, Just before sunrise, And when the temperature of the earth's surface starts to increase. Condensed water in the air may also refract sunlight to produce rainbows. Water runoff often collects over watersheds flowing into rivers. Through erosion, Runoff shapes the environment, Creating river valleys and deltas, Which provide rich soil and level ground for the establishment of population centers. A flood occurs when an area of land, Usually low-lying, Is covered with water which occurs when a river overflows its banks or a storm surge happens. On the other hand, Drought is an extended period of months or years when a region notes a deficiency in its water supply. This occurs when a region receives consistently below average precipitation, Either due to its topography or due to its location in terms of latitude.

Reviews

I never realized there would be so many things to say about water. Very interesting and I slept very well. Thank you very much!