Float
''Float'' is a word with multiple meanings across various fields.
In physics, it refers to the state where an object remains on the surface of a liquid without sinking, governed by buoyancy and Archimedes' principle (see [[Physical Concepts]]).
In mathematics and computing, a float denotes a data type for approximate real numbers in floating-point arithmetic (see [[Mathematics and Computing]]).
In economics and finance, it describes floating exchange rates or the float of shares in stock markets (see [[Economics and Finance]]).
In arts and entertainment, a float is an elaborately decorated platform used in parades (see [[Arts and Entertainment]]).
Other uses include culinary items like root beer float, fishing devices, and aviation terms like floatplanes (see respective sections).
Physical Concepts
Buoyancy and Floating Objects
Buoyancy refers to the upward force exerted by a fluid on an object immersed in it, opposing the object's weight and arising from pressure differences within the fluid.[1] This force enables objects to float or sink depending on their interaction with the surrounding medium.[2]
An object floats when its average density is less than that of the fluid, as the buoyant force then exceeds or equals the object's weight, preventing it from sinking. Conversely, if the object's density exceeds the fluid's, the buoyant force is insufficient to counteract the weight, causing the object to sink. This density comparison determines equilibrium: for floating objects, partial immersion displaces a volume of fluid whose weight matches the object's weight.[3][2]
The magnitude of the buoyant force F_b is quantified by the equation
F_b = \rho_\text{fluid} \, V_\text{displaced} \, g,
where \rho_\text{fluid} is the density of the fluid, V_\text{displaced} is the volume of fluid displaced by the object, and g is the acceleration due to gravity.[4] This relation highlights how displacement directly influences the supportive force in fluids like water or air.
Everyday examples illustrate buoyancy effectively. Ships, constructed from dense steel, float because their overall structure displaces a large volume of water, generating a buoyant force equal to the vessel's total weight.[2] Icebergs float in seawater with about 90% submerged, as ice has a density of approximately 0.917 g/cm³ compared to seawater's 1.025 g/cm³.[5] Similarly, helium-filled balloons rise in air because helium's density (0.1786 kg/m³) is far less than air's (about 1.225 kg/m³), resulting in a net upward buoyant force.[6]
Observations of floating objects date back to antiquity, with ancient Egyptians relying on buoyant reed boats for Nile River navigation as early as 4000 BCE, demonstrating practical understanding of displacement in water.[7] Early Greek thinkers, such as Thales of Miletus around 585 BCE, pondered buoyancy by proposing that the Earth itself floated on water like a disk supported by its "floatiness," linking natural phenomena to fluid support.[8] These early insights laid groundwork for later formalizations, such as Archimedes' principle.[2]
Archimedes' Principle
Archimedes' Principle states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid displaced by the body.[9] This principle applies whether the body is fully or partially submerged and forms the basis for understanding why objects float or sink in fluids.[10]
The principle is attributed to the ancient Greek mathematician Archimedes, who reportedly discovered it around 250 BCE while bathing in Syracuse, Sicily. King Hiero II had commissioned a gold crown for a temple and provided the goldsmith with a specific amount of pure gold, but suspected the finished crown contained silver alloy. Tasked with verifying its purity without damaging it, Archimedes realized in the bath that an object's volume could be measured by the water it displaced; he famously ran through the streets shouting "Eureka!" upon this insight.[11] By comparing the crown's weight to the volume of water it displaced—indicating its density—Archimedes confirmed the fraud.[12]
The principle can be derived from hydrostatics by considering the pressure distribution on an immersed object. The net buoyant force arises from the difference in fluid pressure acting on the object's surfaces, with higher pressure at greater depths. Integrating the hydrostatic pressure p = \rho [g](/page/G) h (where \rho is fluid density, [g](/page/G) is gravitational acceleration, and h is depth) over the object's closed surface yields the vertical component as the weight of the displaced fluid:
F_b = \int_S \mathbf{p} \cdot d\mathbf{A} = \rho g V,
where V is the volume of displaced fluid and the integral is taken over the surface S, with the horizontal components canceling out.[13] This derivation shows that buoyancy is a consequence of the fluid's equilibrium under gravity, independent of the object's shape.[14]
In naval architecture, Archimedes' Principle governs ship design by ensuring the vessel's total weight equals the buoyant force from the displaced seawater volume, allowing steel hulls—denser than water—to float when their overall density is reduced by air-filled compartments.[15] For submarines, ballast tanks are filled or emptied with water to adjust the displaced volume, enabling control of buoyancy: surfacing occurs when tanks are blown with compressed air to expel water and increase V, while diving involves flooding tanks to decrease V and exceed the submarine's weight.
A modern extension of the principle facilitates precise density measurements for irregular objects, such as rocks or artifacts, using overflow methods where the object is submerged in a full container, and the volume of overflowed fluid is collected and measured.[16] Density \rho_{obj} is then calculated as mass divided by this displaced volume, providing a non-destructive technique rooted in Archimedes' original approach to the crown.[17]
Mathematics and Computing
Floating-Point Arithmetic
Floating-point arithmetic provides a method for approximating real numbers in computer systems using a finite number of bits, typically divided into fields for the sign, exponent, and mantissa (also called significand). This representation allows for a wide dynamic range of values, from very small to very large, by scaling the mantissa with the exponent, unlike fixed-point formats where the decimal point position is rigid. The mantissa holds the significant digits, often normalized to lie between 1 and the base (usually 2 for binary systems), while the exponent indicates the scale.[18]
The IEEE 754 standard, first published in 1985 and revised in 2008 and 2019, formalized binary floating-point arithmetic and became the de facto global standard for such computations in modern processors. It specifies single-precision format using 32 bits: 1 bit for the sign, 8 bits for the biased exponent, and 23 bits for the mantissa fraction (with an implicit leading 1 for normalized numbers, yielding 24 bits of precision). Double-precision uses 64 bits: 1 sign bit, 11 exponent bits, and 52 mantissa bits (53 bits of precision including the implicit 1). The exponent is stored as an unsigned integer biased by 127 for single-precision and 1023 for double-precision to accommodate both positive and negative powers of 2 without a sign bit for the exponent itself; for example, a stored exponent of 128 in single-precision represents an actual exponent of 1 (128 - 127). Special values like zero, infinity, and NaN (Not a Number) are handled via reserved exponent patterns.[19][19][20]
The value represented by an IEEE 754 floating-point number is calculated as
(-1)^s \times M \times 2^{E - \text{bias}}
where s is the sign bit (0 for positive, 1 for negative), M is the mantissa interpreted as $1.f(withfthe fractional bits),E$ is the stored exponent, and bias is 127 or 1023 depending on precision. This formulation enables efficient hardware implementation but inherently approximates most real numbers due to limited precision.[18]
Historically, floating-point concepts emerged in the early 1940s with Konrad Zuse's Z3 computer, completed in 1941, which was the first working programmable digital computer and used binary floating-point arithmetic with a 22-bit word length (including 7 exponent bits and 14 mantissa bits) for relay-based calculations. Subsequent machines, such as the IBM 704 in 1954, introduced mass-produced hardware support for floating-point operations, paving the way for broader adoption in scientific computing. The IEEE 754 standardization in 1985 addressed inconsistencies across systems, ensuring portability and reliability in floating-point results.[21][22][19]
Basic operations like addition and multiplication follow algorithms that preserve the format while managing approximation. For multiplication, the mantissas are multiplied (producing a 48-bit result for single-precision), the exponents are added and debiased, the sign is XORed, and the result is normalized (shifted to restore the leading 1) before rounding to fit the mantissa length. Addition requires aligning exponents by right-shifting the mantissa of the number with the smaller exponent (potentially losing precision through denormalization), adding or subtracting the mantissas, then normalizing and rounding the outcome. These steps introduce rounding errors, as the exact result often exceeds the representable precision; IEEE 754 mandates rounding to nearest (with ties to even) to minimize bias, but cumulative operations can amplify errors, leading to precision loss in iterative computations like summation of many terms. For instance, adding a large number to a much smaller one may discard the smaller value entirely due to alignment shifts.[18][23][18]
Data Types in Programming
In the evolution of programming languages, early computers predominantly relied on fixed-point arithmetic for handling fractional numbers due to hardware limitations, but this shifted toward floating-point representations in the late 1950s with the introduction of Fortran, which popularized normalized floating-point for scientific computations to better manage varying magnitudes of numbers.[24] By the 1960s, floating-point data types became a staple in languages like Fortran IV, enabling more flexible numerical simulations and calculations across diverse scales.[25]
Modern programming languages implement floating-point data types following standards like IEEE 754 for consistent representation, with variations in size and precision to balance performance and accuracy. In C and C++, the float type typically occupies 4 bytes (32 bits), providing approximately 7 decimal digits of precision and a range from about 1.18 × 10⁻³⁸ to 3.4 × 10³⁸.[26] This single-precision format is suitable for applications where memory efficiency is prioritized over exactness, such as graphics rendering. In contrast, Java and Python use double as the primary floating-point type, which spans 8 bytes (64 bits) and offers around 15–16 decimal digits of precision, with a vastly larger range up to approximately 1.8 × 10³⁰⁸, making it ideal for most scientific and engineering tasks requiring higher fidelity.[27] Python's float is implemented as a C double under the hood in CPython, ensuring compatibility with C libraries while inheriting its precision characteristics.
In recent years, lower-precision formats such as half-precision (IEEE 754 binary16, 16 bits, with about 3–4 decimal digits and range 5.96 × 10⁻⁸ to 6.55 × 10⁴) and specialized types like bfloat16 (used in AI for gradient computations) and 8-bit floating-point (FP8) have gained prominence, particularly in machine learning and graphics applications for improved efficiency on GPUs and reduced memory usage, supported in libraries like NumPy, PyTorch, and hardware from NVIDIA and others as of 2025.[28][29]
To illustrate basic usage, consider a simple declaration and arithmetic operation in pseudocode, which mirrors syntax in C, Java, or Python:
float pi = 3.14159; // Single-precision approximation
double radius = 5.0; // Double-precision for more accuracy
double area = pi * radius * radius; // Result: approximately 78.5398
float pi = 3.14159; // Single-precision approximation
double radius = 5.0; // Double-precision for more accuracy
double area = pi * radius * radius; // Result: approximately 78.5398
This example highlights how floating-point types store approximations of real numbers, where even a constant like π is rounded to fit the available mantissa bits.[30]
Despite their utility, floating-point data types introduce several common pitfalls that can lead to subtle errors in programs. Catastrophic cancellation occurs when subtracting two nearly equal floating-point numbers, amplifying rounding errors from earlier operations and potentially resulting in a loss of significant digits; for instance, computing the difference between 1.000001 and 1.000000 might yield zero due to precision limits rather than the expected small value.[30] Machine epsilon, defined as the smallest positive floating-point number ε such that 1 + ε ≠ 1 in the computer's arithmetic (approximately 2.22 × 10⁻¹⁶ for double precision), quantifies this rounding gap and is crucial for understanding tolerance in comparisons or iterative algorithms.[30] Additionally, special values like NaN (Not a Number), arising from operations such as 0/0 or √(-1), and infinity (from overflow like 1/0) propagate through computations and require explicit handling—such as checking isnan() or isfinite() in C—to avoid invalid results in numerical software.[30]
For scenarios demanding exact decimal arithmetic, such as financial calculations where binary floating-point approximations can accumulate errors (e.g., 0.1 + 0.2 ≠ 0.3 exactly), languages provide specialized libraries as alternatives to native floats. In Python, the decimal module implements arbitrary-precision decimal floating-point arithmetic, allowing users to set precise rounding modes and avoid binary representation issues for base-10 exactness.[31] Similarly, Java's BigDecimal class supports immutable, arbitrary-precision signed decimal numbers, constructed from strings or integers to preserve exact scales during operations like addition or division, which is essential for applications like currency handling.[32] These alternatives trade computational speed for reliability, often at the cost of 10–100 times slower performance compared to native doubles.[30]
Economics and Finance
Floating Exchange Rates
A floating exchange rate is a currency valuation system in which the price of one currency relative to another is primarily determined by the supply and demand dynamics in the foreign exchange (forex) market, contrasting with fixed exchange rate regimes where governments or central banks peg the currency to a specific value or another asset.[33] In this system, market forces such as trade flows, investment decisions, and speculation drive fluctuations, allowing currencies to appreciate or depreciate without direct official intervention to maintain a fixed parity.[34]
One key advantage of floating exchange rates is their ability to automatically adjust to economic shocks, such as changes in productivity or commodity prices, which helps restore trade balances over time by making exports more competitive during depreciations or imports cheaper during appreciations.[34] This flexibility reduces the need for painful domestic policy adjustments, like austerity measures, that are often required under fixed regimes to defend a peg.[35] Additionally, floating rates promote monetary policy independence, enabling central banks to focus on domestic goals like inflation control rather than defending exchange rate targets.[33]
The modern era of floating exchange rates emerged following the collapse of the Bretton Woods system in 1971, when U.S. President Richard Nixon suspended the dollar's convertibility into gold, effectively ending the fixed exchange rate framework established in 1944.[36] This "Nixon Shock" led to a period of turmoil, with major currencies like the U.S. dollar and Japanese yen initially floating temporarily, and by March 1973, widespread adoption of floating rates among industrialized nations as attempts to restore fixed parities failed.[37] The shift marked a transition to a more market-driven international monetary system, with numerous countries, particularly among industrialized nations, operating floating or managed floating regimes by the late 1970s. As of 2023, according to the IMF, approximately 35 countries maintain free floating regimes and 49 have floating arrangements, representing about 44% of member countries, with many others using managed floats.[38]
For example, the USD/EUR exchange rate has exhibited significant fluctuations driven by divergences in interest rates and inflation between the United States and the Eurozone; during 2022, the euro depreciated sharply against the dollar as the Federal Reserve raised rates more aggressively than the European Central Bank to combat higher U.S. inflation, reaching parity levels not seen since 2002.[39] Such movements reflect how higher interest rates in one region attract capital inflows, strengthening its currency, while elevated inflation erodes purchasing power and pressures depreciation.[39]
Although floating rates are market-determined, central banks often engage in occasional interventions to mitigate excessive volatility or address disorderly market conditions, such as selling foreign reserves to support a depreciating currency during sudden capital outflows.[40] These "managed floats" aim to smooth short-term swings without targeting a specific rate, as seen in interventions by the Swiss National Bank in 2011 to cap the franc's appreciation amid the eurozone debt crisis.[41] Such actions are typically sterilized—offset by domestic monetary operations—to avoid broader impacts on the money supply.[42]
Float in Stock Markets
In stock markets, the float refers to the number of a company's shares that are available for trading by the public, excluding those held by insiders, major shareholders, or under restrictions such as lock-up agreements.[43] This metric represents the portion of outstanding shares that can be freely bought and sold, providing a key indicator of a stock's market availability.[44]
The float is calculated by subtracting restricted shares—typically those owned by company officers, directors, or large institutional investors—from the total issued or outstanding shares.[45] For example, if a company has 100 million outstanding shares and 20 million are restricted, the float would be 80 million shares.[46] The U.S. Securities and Exchange Commission (SEC) defines public float more precisely as the aggregate worldwide number of shares of voting and non-voting common equity held by non-affiliates, often used in regulatory contexts like determining reporting requirements.[47]
Historically, the concept of float developed alongside the growth of organized stock exchanges in the 19th century, as trading volumes increased and distinctions arose between shares held by founders or insiders and those accessible to the broader public; the New York Stock Exchange, formalized in 1817, marked an early institutionalization of such share trading dynamics.[48] Modern regulations governing float, including disclosure requirements for restricted shares, were established by the SEC under the Securities Exchange Act of 1934 to promote transparency and protect investors.[49]
A related concept is clearance float, which describes the time delay between trade execution and final settlement, during which shares and funds are effectively "floating" in the system; in the U.S., this was shortened to T+2 business days in 2017 and further to T+1 effective May 28, 2024, to reduce counterparty risk and improve efficiency.[50][51] The size of the float significantly impacts stock liquidity: a high float generally enhances liquidity by allowing more shares to absorb buy and sell orders without large price impacts, thereby reducing volatility, while a low float can lead to heightened price swings due to limited supply.[44][52] For instance, stocks with floats under 10 million shares are often considered low-float and prone to rapid price movements on moderate trading volume.[46]
Arts and Entertainment
Parade Floats
Parade floats are elaborate, mobile platforms mounted on wheeled chassis, such as trucks or trailers, designed to serve as moving stages in public processions, often decorated with thematic elements like flowers, sculptures, animatronics, and lighting to convey stories or celebrate cultural motifs.[53] These structures allow performers, such as dancers or musicians, to participate while the float travels along a parade route, enhancing the visual spectacle of events like festivals and holidays.
The origins of parade floats trace back to medieval Europe, where "pageant wagons" functioned as wheeled stages for religious plays and processions, transporting actors and scenery during community gatherings.[54] In the United States, floats gained prominence during the Mardi Gras celebrations in New Orleans, with informal processions featuring decorated carts, including cotton carts, occurring in the 1830s, evolving from French and European carnival traditions brought by settlers, and the first organized parade in 1857 by the Mystick Krewe of Comus.[55] The Tournament of Roses Parade in Pasadena, California, further popularized floral floats starting in 1890, when horse-drawn carriages adorned with flowers marked the inaugural event to showcase the region's mild winter climate.[56]
Construction of modern parade floats begins with a sturdy base frame made from steel tubing and plates, powered by gas engines for propulsion and steering, often incorporating hydraulic systems to enable moving parts like rotating elements or elevating sections for dramatic effect.[57] The superstructure is typically formed using chicken wire stretched over wooden or PVC frameworks to create shapes, which are then padded with floral foam— a water-absorbent material that supports thousands of fresh flowers glued in place to cover the surface entirely, as required in events like the Rose Parade.[53] Additional embellishments include LED string lights for nighttime visibility and animatronic figures for thematic animation, with volunteer teams spending months assembling these multi-ton creations in specialized workshops.[58]
Parade floats hold deep cultural significance as symbols of community identity and festivity, fostering social unity and storytelling in traditions worldwide. In Brazil's Carnival, particularly the Rio de Janeiro samba school parades, floats serve as narrative vehicles that depict historical events, social commentary, or folklore through elaborate designs, competing for prestige and reinforcing cultural heritage since their introduction in the early 20th century.[59] Similarly, in the United States, the Macy's Thanksgiving Day Parade uses floats to promote joy and consumerism, with giant balloon versions symbolizing American pop culture and drawing millions annually since 1924.[60]
Notable examples include Macy's Parade floats featuring iconic pop culture characters, such as the Snoopy balloon atop his doghouse, which has appeared in various iterations since 1968 to represent whimsy and holiday cheer, or the Kermit the Frog float from 1977, embodying Muppet entertainment.[61] In the Rose Parade, floats like the 2023 "Turning the Page" entry by City of Hope, adorned with over 40,000 roses and depicting a book transforming into a butterfly, highlight themes of hope and renewal using all-natural floral materials.[53]
In music, the term "float" has inspired numerous titles and themes, often evoking sensations of buoyancy, freedom, or emotional detachment across genres. One seminal example is the 1977 R&B single "Float On" by The Floaters, which peaked at number two on the Billboard Hot 100 for two weeks and held the number-one spot on the R&B chart for six weeks, blending zodiac sign introductions with smooth harmonies to symbolize effortless connection in relationships. The song's innovative spoken-word structure and crossover appeal marked an early mainstream use of "float" as a metaphor for lighthearted romance, influencing soul and disco trends.
Transitioning to rock and alternative scenes in the late 1990s and early 2000s, Bush released the track "Float" on their 2001 album Golden State, which debuted at number 22 on the Billboard 200 and featured the song's introspective lyrics about navigating chaos and disconnection, with Gavin Rossdale's vocals gliding over grunge-infused guitars to convey a sense of surreal detachment. Similarly, Modest Mouse's "Float On," the lead single from their 2004 album Good News for People Who Love Bad News, became a breakthrough hit, reaching number 68 on the Billboard Hot 100 and topping the Alternative Songs chart for eight weeks while earning a Grammy nomination for Best Rock Song. The track's optimistic yet wry lyrics, describing resilience amid misfortune, captured indie rock's evolution toward accessible anthems of perseverance, propelling the album to platinum status.
In the Celtic punk genre, Flogging Molly's 2008 album Float debuted at number four on the Billboard 200, showcasing the band's signature blend of Irish folk and punk energy through tracks like the title song, which uses "float" to symbolize drifting through life's uncertainties with defiant spirit. The album received critical acclaim for its thematic depth, including explorations of immigration and loss, and solidified the band's role in bridging traditional roots music with modern punk audiences. By the 2010s, "float" appeared in hip-hop lyrics to denote effortless success or emotional elevation, as in Drake's 2011 track "Headlines" from Take Care, where lines like "They know, they know, they know" paired with floating ad-libs evoke a detached supremacy over industry pressures, contributing to the album's diamond certification.
Beyond music, "float" has themed visual media, notably Pixar's 2019 animated short Float, directed by Bobby Rubio, which premiered at the Tribeca Film Festival and later streamed on Disney+, portraying a father's protective journey with his levitating son as an allegory for neurodiversity and acceptance, earning praise for its emotional subtlety and inclusive storytelling.[62] In television, the ABC sitcom The Goldbergs referenced parade floats in its 2016 episode "Ho-ly K.I.T.T.," where characters attend the Philadelphia Thanksgiving Day Parade to see a Knight Rider-themed float, humorously highlighting family enthusiasm for pop culture spectacles.
The motif's evolution reflects shifting cultural contexts: from the 1970s' feel-good escapism in R&B to 2000s indie and punk's introspective buoyancy amid personal turmoil, and into 2010s hip-hop and media's emphasis on resilience and identity, often tied to chart-topping successes like Modest Mouse's eight-week Alternative chart reign or Flogging Molly's top-five album debut, underscoring "float"'s enduring appeal as a symbol of transcendence.
Food and Beverages
Root Beer Float
The root beer float is a classic American dessert beverage consisting of vanilla ice cream scooped into a tall glass and slowly topped with chilled root beer, which causes the carbonation to react with the ice cream and create a frothy, creamy foam on top.[63] This simple preparation, typically using one or two scoops of ice cream and about 8-12 ounces of root beer per serving, emphasizes the contrast between the cold, dense ice cream and the effervescent soda, resulting in a sweet, nostalgic treat often garnished with whipped cream or a maraschino cherry.[63]
The root beer float originated in 19th-century United States soda fountains, with its invention credited to Frank J. Wisner, a Colorado gold mine owner and brewer, in August 1893.[64] Inspired by the sight of snow-capped Cow Mountain resembling ice cream floating in dark root beer at dusk, Wisner experimented at his Cripple Creek soda fountain by adding vanilla ice cream to root beer, initially naming the drink the "Black Cow" after the mountain's appearance.[64] The treat gained widespread popularity during the Prohibition era (1920–1933) as a non-alcoholic alternative, promoted by root beer chains like A&W, which had opened its first stand in 1919 and capitalized on the boom in sodas and drive-in culture.[65]
Variations on the root beer float include using chocolate ice cream or drizzling chocolate syrup into the glass for a richer, cocoa-infused version, or substituting coffee ice cream for a caffeinated twist that blends the soda's herbal notes with roasted flavors.[66] Internationally, adaptations like Japan's cream soda float—made with bright green melon soda, vanilla ice cream, and sometimes a preserved cherry—offer a similar fizzy, creamy profile but with a fruitier, less sarsaparilla-based taste, reflecting local soda preferences since the mid-20th century.[67]
Nutritionally, a standard root beer float is high in sugar, primarily from the soda and ice cream, contributing to its indulgent appeal but also its limited health benefits, with a typical 12-16 ounce serving containing around 300 calories, including significant amounts of added sugars and saturated fats.[68] In American culture, the root beer float has become an enduring icon of mid-20th-century diners and drive-ins, evoking postwar leisure and family outings as a staple at soda fountains and fast-food spots from the 1950s onward.[65]
Other Culinary Uses
Beyond the classic root beer float, the concept of "float" in culinary contexts extends to techniques where lighter elements are delicately positioned atop denser liquids to create visual and textural contrast. One prominent example is the French dessert known as îles flottantes (floating islands), consisting of poached meringue "islands" served in a pool of crème anglaise custard. Originating in the 17th century with early recipes documented by François-Pierre de la Varenne, the father of classic French cuisine, this dish evolved through the centuries and was refined by chef Auguste Escoffier in the early 20th century, who incorporated tropical variations in his 1902 publication.[69][70]
In savory applications, the float technique appears in Asian soups, particularly Chinese egg drop soup (dànhuātāng), where lightly beaten eggs are slowly poured into simmering broth, forming wispy, floating strands or ribbons as they cook. This method is a traditional element of Chinese cuisine with origins dating back to ancient times, possibly the Han Dynasty (206 BCE–220 CE).[71] Similar egg floats are used in other Asian broths, such as Japanese tamago toji in udon soups.[72]
Modern interpretations incorporate molecular gastronomy, where liquid nitrogen is employed to instantly freeze ice cream bases, creating ultra-smooth textures for floats that enhance the traditional ice cream-based drinks. This technique, popularized in the late 20th century by chefs like Heston Blumenthal, allows for rapid freezing at -196°C, minimizing ice crystal formation and enabling creative floats with infused flavors that remain buoyant on beverages.[73]
Regionally, floats manifest in diverse forms, such as British sherry float cocktails, where a layer of sherry is gently floated atop mixed drinks like flips or cobblers for a stratified effect, a practice dating to 19th-century tavern recipes emphasizing sherry's role in English mixology. In Indian cuisine, ras malai, a Bengali dessert from the 19th century, features soft chenna (cottage cheese) balls that float in thickened, saffron-infused milk (ras), absorbing flavors while maintaining buoyancy.[74][75]
Successful preparation of these floats hinges on temperature control to ensure elements remain afloat: for meringues, poaching in milk heated to a gentle simmer (around 80-85°C) prevents deflation and sinking, while whisking egg whites at low speed builds stable foam; in egg drops, the broth must reach a rolling boil before adding eggs to promote even dispersion without clumping.[76][72]
Fishing Floats
Fishing floats, also known as bobbers, are essential devices in angling that serve as visual indicators for detecting fish bites while maintaining bait at a desired depth. These lightweight buoys attach to the fishing line and float on the water's surface, providing buoyancy to suspend hooks and bait below. When a fish strikes, the float typically dips, tilts, or submerges, alerting the angler to set the hook promptly.[77]
The earliest known use of fishing floats dates back to at least the fourth century AD, with the first detailed written description appearing in the 1496 Treatyse of Fishing with an Angle, which details methods for making floats from cork or quills for trout fishing.[78] Modern plastic floats emerged in the mid-20th century, coinciding with the rise of synthetic materials in tackle manufacturing, replacing traditional natural options for greater durability and affordability. In recent years, electronic fishing floats equipped with LED lights and sensors to detect bites have become available, providing visual or app-based alerts, particularly useful for night fishing.[79]
Fishing floats come in two primary types: fixed and slip. Fixed floats, often clip-on or spring-loaded, attach securely to the line at a set position, ideal for shallow waters or precise depth control up to about 6 feet.[80] Slip floats, by contrast, slide freely along the line until stopped by a bead or knot, allowing easy adjustment for deeper presentations—typically 8 to 20 feet—without re-rigging, which makes them versatile for varying conditions.[81] Materials vary to suit sensitivity and durability; cork provides natural buoyancy and subtle action for panfish, while porcupine or goose quills offer lightweight, responsive indicators for finicky bites in clear water. Plastic versions, molded from high-impact polymers, resist waterlogging and are common in contemporary setups for their bright visibility and robustness.[82][83]
The core function of a fishing float is to balance buoyancy against the weight of the bait, line, and sinkers, ensuring the bait hovers at the target depth while remaining detectable. Buoyancy is tuned by selecting a float size and material that matches the rig's total weight—smaller, lighter floats (e.g., 1-2 grams) for delicate presentations, and larger ones (up to 10 grams) for heavier baits in current. Upon a strike, the float's movement—submersion or sideways tip—signals the angler, as the fish's pull overcomes the float's neutral position.[81][77] This setup prevents bait from drifting too deep or shallow, increasing strike detection in low-visibility conditions.[84]
In techniques like stillwater angling, floats excel for targeting suspended fish such as crappie or walleye in lakes, where a slip float rig allows probing stratified depths. For fly fishing in stillwaters, a float acts as an indicator in nymphing setups, suspending weighted flies beneath a tapered leader to mimic drifting insects. A basic slip float setup involves threading the line through the float, followed by a bobber stop (rubber bead and knot) to set depth, a small split-shot sinker 12-18 inches above the hook, and bait or fly at the end—ensuring the float sits half-submerged for sensitivity.
Line (main) --> Slip Float --> Bobber Stop (bead + knot) --> Split Shot (1-2) --> Leader (12-24") --> Hook/Bait/Fly
Line (main) --> Slip Float --> Bobber Stop (bead + knot) --> Split Shot (1-2) --> Leader (12-24") --> Hook/Bait/Fly
This configuration, adjustable via the stop, facilitates casts up to 50 feet and quick depth changes (e.g., from 5 to 15 feet) during a session.[81][85]
In competitive fishing tournaments, regulations often govern tackle to promote fairness, with organizations like the International Game Fish Association (IGFA) imposing general limits on line class and rod components. Some specialized match angling events may include restrictions on float sizes to ensure equitable competition. Local bass or crappie tournaments may enforce uniform tackle inspections.
In construction and plumbing, a float is a fundamental hand tool used for smoothing and leveling surfaces during the application of plaster, mortar, or concrete. The plasterer's float, typically a flat rectangular tool with a wooden or rubber pad attached to a handle, is employed to apply, spread, and finish plaster or mortar on walls and ceilings, ensuring an even, compact surface free of trowel marks.[86] Wooden versions provide a textured finish suitable for initial coats, while rubber pads offer flexibility for smoother, more polished results on finer layers.[87]
The concrete float serves a similar purpose in masonry work, featuring a blade made of magnesium, wood, or resin to trowel and smooth wet cement surfaces, which helps embed aggregate and prevent surface cracks by promoting uniform water distribution and curing.[88] Magnesium blades, prized for their lightweight durability and ability to retain air in the mix, are particularly effective for large-scale pours, while wood options absorb excess moisture to avoid overworking the surface.[88]
These tools trace their origins to ancient Roman construction practices, where wooden implements were used for applying lime-based stuccos; Vitruvius's De Architectura outlined recipes for smooth plaster finishes.[89] By the 19th century, with the invention of Portland cement in 1824 and the standardization of reinforced concrete techniques, floats evolved into more precise instruments tailored for industrial-scale building, enabling consistent finishes on expansive surfaces.[90]
Key techniques involve the bull float for initial leveling on large areas, where the tool is pushed and swept in overlapping arcs to flatten the surface, fill voids, and draw up the cement paste (or "cream") without sealing it prematurely, thus aiding proper hydration and crack prevention.[91] For detailed finishing, the hand float is then used in similar sweeping motions after edging, providing precise control to eliminate coarseness and achieve a uniform texture before final troweling.[91]
Proper maintenance extends tool life and ensures performance; after each use, floats should be cleaned with water and a mild abrasive to remove residue, then dried thoroughly and stored in a moisture-free environment to prevent rust on metal components or degradation of wooden and rubber parts.[92] Safety considerations include selecting floats with ergonomic handles that reduce wrist strain during repetitive motions, helping mitigate repetitive strain injuries common in construction trades.[93]
Transportation
Floatplanes
Floatplanes are a type of seaplane equipped with buoyant pontoons or floats mounted beneath the fuselage, replacing traditional wheeled landing gear to enable takeoff and landing on water surfaces. These aircraft, often derived from conventional landplanes, feature streamlined pontoons that provide hydrodynamic lift during water operations, with some designs incorporating retractable wheels within the floats for amphibious capabilities, allowing transitions between water and land without external modifications. The pontoon configuration contrasts with flying boats, which integrate a hull-shaped fuselage directly for buoyancy, emphasizing the floatplane's modular undercarriage approach for versatility in diverse environments.[94][95][96]
The development of floatplanes began in the early 1910s, pioneered by American aviation innovator Glenn Curtiss, who achieved the first successful powered seaplane flight in the United States on January 26, 1911, using a modified biplane fitted with floats. Curtiss's experiments, including the 1911 Model D with a central float and outrigger pontoons, laid the groundwork for practical water-based aviation, advancing designs for naval applications. During World War II, floatplanes played a crucial role in maritime patrols, reconnaissance, and search-and-rescue missions; for instance, U.S. Navy scout floatplanes like the Curtiss SOC Seagull were catapult-launched from cruisers to spot enemy submarines and surface vessels, extending over-the-horizon visibility. Postwar, floatplanes evolved into modern bush planes, such as the De Havilland Canada DHC-2 Beaver and DHC-6 Twin Otter on floats, optimized for rugged, short takeoff and landing (STOL) performance in remote terrains.[97][98][99][100]
Operational challenges for floatplanes include managing water conditions, such as waves that can cause porpoising or instability during takeoff and landing, requiring pilots to maintain precise airspeed and attitude to avoid structural stress on the pontoons. Beaching gear—temporary wheeled dollies attached to the floats—facilitates pulling the aircraft ashore on sandy or gravel beaches, preventing hull damage and enabling maintenance in areas without docks, though improper use can lead to gear entanglement in soft substrates. A representative example is the Cessna 185 Skywagon equipped with floats, a popular choice for its robust six-cylinder engine and payload capacity of around 900 pounds, which handles rough water better than lighter trainers but demands vigilant pre-flight inspections of float struts and water rudders.[101][102][103]
One primary advantage of floatplanes is their ability to access isolated regions without established runways or infrastructure, making them indispensable for delivering supplies, conducting surveys, or supporting emergency services in archipelagos and wilderness areas. In modern applications as of 2025, floatplanes remain vital in Alaska and Canada, where they facilitate tourism and fishing charters; operators like those at Tikchik Narrows Lodge use De Havilland Beavers and Cessna 206s on floats to reach remote lakes for fly-in fishing trips targeting salmon and trout, covering hundreds of square miles in the Togiak National Wildlife Refuge. Similarly, in northern Manitoba, charters such as those from Gangler's North Seal River Lodge employ float-equipped aircraft for multi-day excursions to fly-in lodges, providing efficient transport over roadless terrains while adhering to updated environmental regulations for noise and wildlife disturbance.[104][105][106][107]
Floatation in Vehicles
Floatation in vehicles refers to the use of buoyancy principles to enable operation on water, primarily through watertight designs, foam materials, and strategic weight distribution in amphibious cars, boats, and military transports. Early experiments in amphibious vehicle design date back to the late 18th and early 19th centuries, with American inventor Oliver Evans constructing the Oruktor Amphibolos in 1805, a steam-powered dredger capable of land and water travel that demonstrated basic buoyancy via its hull displacement.[108]
Post-World War II military applications advanced floatation significantly, exemplified by the DUKW, a 2.5-ton six-wheel-drive amphibious truck developed by GMC in 1942 and produced through 1945 for ferrying supplies and troops from ships to beaches during invasions like Normandy. Over 21,000 units were built, featuring a watertight hull and propeller for seamless land-to-water transitions, providing critical logistical flexibility in amphibious operations. In civilian contexts, the Amphicar Model 770, produced from 1961 to 1968 in West Germany, represented a consumer amphibious car with a watertight body, double-seal doors, and twin propellers driven by a 43-horsepower engine, allowing it to achieve 7 knots on water despite modest land performance. These designs relied on hull buoyancy to support vehicle weight, preventing submersion during water travel.[109][110][111]
For small boats and recreational craft, floatation is mandated by U.S. Coast Guard regulations to ensure unsinkability, requiring foam-filled hulls in vessels under 20 feet to provide level flotation even when swamped. These standards, outlined in the Boat Builder's Handbook, specify that closed-cell polyurethane foam must occupy sufficient volume—typically 15-20% of hull displacement—to generate buoyancy exceeding the boat's weight plus maximum load, distributed in compartments to maintain stability and prevent capsizing. In engineering terms, buoyant materials like foam are strategically placed low in the hull and bilges to lower the center of gravity, enhancing metacentric height for roll stability on water, as detailed in military design handbooks for wheeled amphibians. This distribution counters hydrodynamic forces, ensuring the vehicle remains upright under wave action or uneven loading.[112][113][114]
Modern innovations build on these principles with electric propulsion and enhanced flood resistance. The WaterCar EV, introduced in the 2020s, is a street-legal electric amphibious vehicle with a watertight hull and battery-powered props, achieving 5-7 mph on water while complying with road standards. Similarly, the BYD Yangwang U8 electric SUV, launched in 2024, features four electric motors and retractable propellers for brief water traversal, using its sealed body for buoyancy in emergencies like floods. For unmanned systems, amphibious drones such as the miniaturized UAV developed in 2024 integrate buoyant composites for air-water transitions, enabling autonomous surveillance in marine environments. In flood-prone areas, vehicle buoyancy from air-filled tires provides temporary flotation—up to 0.3-0.5 meters of water depth—before hydrodynamic drag destabilizes the chassis, as analyzed in studies of submerged vehicle forces. These advancements prioritize lightweight, distributed foam and sealed compartments for dual-domain stability without compromising land mobility.[115][116][117][118]