Name: water molecules and surface tension
Uploaded: 2019-03-11T09:21:00.000Z
Duration: 1 min 7 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Earth and Environmental Science

Earth's Systems

ESS.EES.3.1

Cohesion

응집력이란같은 종류의 분자가 서로 달라붙으려 하는 성질을 뜻합니다.전형적인 예로는 물이 있습니다.여러 개의 분자가 물방울을 형성하는 것은분자들이 수소 결합을 통해 응집력이 생기면서 가능한 것입니다.물방울이 모이면,표면 쪽에 있는 몇몇 분자들은 공기에 노출됩니다.달라붙을 수 있는 적절한 물질이 이 접점에는 없기 때문에,물방울들은 서로에게 끌리게 되며,안쪽으로 끌어당기는 힘이 생겨납니다.그러한 끌림은 여러 개의 결합을 생성하고,응력 상황에서 파열을 견딜 수 있는 표면을 생성하는데,이러한 현상을 표면 장력이라고 합니다.이러한 현상의 결과로써, 작은 물체들이 물 위를 걸을 수 있게 됩니다.그 물체가 존재하는 응집력을 깨트리지 않는 한 말이죠.

양, 은진, 손재학, 이상임, Piotr G. Jablonski, 김호영. "Water Striders Adjust Leg Movement Speed를 to Optimize Takeling to Takes Off Speed for Their Morphology." Nature Communications 7 (2016년 12월 7일). [<a href="https://doi.org/10.1038/ncomms13698">출처</a>]

응집력

응집력(cohesion)은 동일한 유형의 분자(예: 물 분자)가 서로 끌어당기는 인력입니다. 예를 들어 부분적으로 음전하를 띠는 한 물 분자의 산소는 부분적으로 양전하를 띠는 다른 물 분자의 수소에 수소결합을 합니다. 이런 식으로 물 분자는 다른 물 분자와 최대 4개의 수소결합을 형성할 수 있습니다.
 
 어떤 표면에서 여러 개의 물 분자가 응집력을 통해 모이면 물방울이 형성됩니다. 물은 일반적으로 표면 전체에 퍼지지 않습니다. 이는 물 분자가 표면이나 주변 공기를 구성하는 분자보다 서로에게 더 끌리기 때문입니다.
 
 표면장력(surface tension)은 응집력으로 인해 발생합니다. 소금쟁이는 이 표면장력을 이용해 물 위를 걷습니다. 표면장력은 물과 공기 사이의 단면(즉, 수면)에서 발생합니다. 물 분자는 공기 중의 분자보다 서로에게 더 이끌리기에 표면에 있는 물 분자는 자신의 옆과 아래에 인접한 물 분자와 결합 합니다. 표면 물 분자는 특히 한 쪽(공기쪽)으론 다른 물 분자와 결합을 형성할 수 없기 때문에 주변 물 분자와 더 강한 결합을 형성 합니다. 이렇게 강하게 결합된 분자는 압축된 표면적을 가지고 있어 구형의 물방울을 만들고, 물의 높은 표면장력과 소금쟁이 다리의 부력은 곤충이 수면 위에 머무를 수 있게 합니다.
 
 수은은 쉽게 찾아볼 수 있는 또 다른 응집성 분자입니다. 유리용기에서 수은은 수은 분자 간의 응집력이 수은과 유리 사이의 부착력 보다 강해서 때문에 유리 전체로 퍼지거나 유리를 적시지 않습니다. 반면 물은 응집력이 뛰어나지만 유리 속 규소에 대한 부착력도 있어 유리용기의 바닥에 고르게 분산됩니다.

응집력은 물 분자와 같은 동일한 유형의 분자 사이의 인력입니다. 물 분자는 전체적으로 중성 전하를 띠지만 극성입니다 ...

Education

교육

JoVE Core

Biology

생물학

Fundamentals

기초 원리

Chemistry of Life

생명의 화학

KEY TERMS AND CONCEPTS

주요 용어 및 개념

water molecules and surface tension

Water molecules stick to each other through cohesion. Water is neutral overall, but it is a polar molecule. The oxygen atom in one water molecule has a partial negative charge, and it can bind with a hydrogen atom that has a partial positive charge in another water molecule. This forms a hydrogen bond. Each water molecule can form up to four hydrogen bonds with other water molecules, and these bonds give water its cohesive nature.

Cohesion helps water form droplets on a surface. Water does not usually spread out because the water molecules are more attracted to each other than to the surface or the air around them. The attraction between water molecules at the surface and the bulk water is called surface tension, and it comes from cohesion. At the water-air boundary, surface molecules can only make hydrogen bonds beside and below them. That limited bonding creates a compressed surface area and spherical droplets.

Surface tension is strong enough to support pond skaters, also called water striders. These insects use the surface of water to walk across it. Their buoyant legs and the high surface tension of water help them stay on top of the water.

Mercury is another cohesive liquid. In a glass container, mercury stays in spherical droplets because the cohesive forces between mercury molecules are stronger than the adhesive forces between mercury and glass. Water is also highly cohesive, but it has an affinity for silica, which is a main component of glass. Because of that, water spreads evenly at the bottom of a glass container.

Water Molecules and Surface Tension

the periodic table and organismal elements

the-periodic-table-and-organismal-elements

Periodic Table Basics for Living Things

The periodic table helps explain which elements living things need and how those elements are related. Elements are the smallest units of matter that cannot be broken down further by chemical processes. There are 118 known elements, but not all occur naturally, and even fewer are essential for life. Living matter is made mostly of carbon, nitrogen, hydrogen, and oxygen. Together, these elements make up most of the human body and are also found in all life on Earth. Smaller amounts of calcium,...

atomic structure

Atoms and Their Subatomic Particles

Atoms are the smallest units of elements, and they make up all matter. Each atom contains three subatomic particles: protons, neutrons, and electrons. These particles give an atom its mass and its charge. The idea that matter is made of tiny particles goes back to Democritus, a Greek philosopher around 450 B.C. He used the word atomos, which means “indivisible.” The idea was not accepted at the time, but it returned many centuries later. In the 19th century, John Dalton proposed an atomic...

isotopes

Atomic Mass and Isotope Basics

Atomic mass and isotopes are linked by the number of protons and neutrons in an atom. The number of protons sets an element’s atomic number, or Z. For example, every atom with eight protons is oxygen. Atoms of the same element can still differ because they can have different numbers of neutrons. The mass number, or A, is the total of protons and neutrons. Atoms with the same atomic number but different mass numbers are called isotopes. Elements can have several isotopes. Carbon-12, carbon-13,...

electron behavior

Electron Shells and Valence Electrons

Electrons are negatively charged subatomic particles that occupy regions around the positively charged nucleus of an atom. Their location is linked to energy levels called shells. They are also grouped into sub-shells and orbitals within each shell. An electron’s shell shows its general energy level. Electrons closer to the nucleus have less energy, while electrons farther away have more energy. The sub-shell gives a more exact location and energy level. An orbital is the shape of the region...

electron orbital model

Electron Orbitals and Energy Levels

Electron orbitals show where electrons are most likely to be found around the atomic nucleus. They also help explain energy levels, orbital shapes, and three-dimensional orientation. In an atom, electron location is described first by a shell, or principal energy level. It is then described by a subshell within that shell and by the individual orbitals inside each subshell. The first shell is closest to the nucleus. It has only one subshell and one spherical orbital, called the 1s orbital.

covalent bonds

Electronegativity and Covalent Bond Polarity

Covalent bonds form when two atoms share electrons to fill their valence shells. The way those shared electrons are pulled depends on electronegativity, which is an atom’s ability to attract electrons in a bond. When atoms have similar electronegativities, they form nonpolar covalent bonds. When their electronegativities differ, the bond is polar because the electrons are shared unevenly. The number of covalent bonds an atom can make depends on its valence electrons. Oxygen has six valence...

ionic bonds

Ionic Compounds and Electrolytes

Ionic compounds form when atoms gain or lose electrons to reach a more stable electron configuration. The charged particles that result are called ions. Ionic bonds are electrostatic attractions between oppositely charged ions. The most reactive elements include those with one valence electron, such as potassium, and those that need one more valence electron, such as chlorine. Ions that lose electrons become positive cations. Ions that gain electrons become negative anions. Cations and anions...

hydrogen bonds

Hydrogen Bonds in Water

Hydrogen bonds in water are weak attractions between atoms that are already part of other chemical bonds. One atom is electronegative, such as oxygen, and carries a partial negative charge. The other is a hydrogen atom that is bonded to another electronegative atom and has a partial positive charge. These attractions form because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom like oxygen or nitrogen. The electrons in that bond are shared unequally.

van der waals interactions

Intermolecular Forces in Polar Solutions

Intermolecular forces are the attractions and repulsions that act between atoms and molecules. These electrostatic forces come from particles with permanent, partial, or temporary charges. For neutral atoms and molecules, the main types are ion-dipole, dipole-dipole, and dispersion forces, which are together called van der Waals forces. Polar molecules have a partial positive end and a partial negative end. That separation of charge creates a dipole. In water, oxygen is more electronegative...

elements and compounds

Elements, Compounds, and Bonding

Elements and compounds are the two main kinds of pure substances. A pure substance contains only one kind of matter. An element contains only one type of atom. A compound contains two or more types of atoms joined by a chemical bond. Elements can be atomic or molecular, depending on their basic units. They are unique forms of matter with specific chemical and physical properties. Ordinary chemical reactions cannot break an element into a smaller substance. There are 118 elements, but only 98...

molecular shapes

Electron Geometry and Lone Pairs

Electron geometry and lone pairs help explain why molecules take specific shapes. The arrangement of electron groups around a central atom controls the molecular geometry. Valence electrons form bonding pairs, which sit mainly between bonded atoms, or lone pairs, which belong to one atom only. Electron pairs in the valence shell spread out to reduce repulsion. They do this by maximizing the distance between one another. A diatomic molecule has two regions of electron density, and these are...

pH Scale in Everyday Solutions

pH measures how acidic or basic a water-based solution is. It depends on the concentration of hydronium ions, H3O+, in the solution. In one liter of pure water at neutral pH, there are 1×10−7 moles of hydronium ions. Because hydronium ion levels can vary over a very wide range, measuring pH directly in moles is not practical. The pH scale converts hydronium ion concentration into a negative logarithm. Pure water has a pH of 7 and is neutral. Most solutions fall between 0 and 14, but some, such...

chemical reactions

Atoms, Bonds, and Chemical Reactions

Chemical reactions rearrange atoms to form new substances. In a reaction, the starting materials are called reactants, and the new substances are called products. The atoms stay the same type and number, but their bonds change, so the substances become different compounds. During a chemical reaction, bonds between atoms break and form again. This means the shared electrons are rearranged. Some reactions happen on their own, while others need an energy source such as heat or light. In biology,...

redox reactions

Electron Transfer in Redox

Redox reactions are chemical reactions that involve electron transfer between atoms or molecules. When one particle gains electrons, another must lose them at the same time. That is why oxidation and reduction always happen together. The two roles in a redox reaction are linked. The atom that is oxidized acts as the reducing agent, or reductant. The atom that is reduced acts as the oxidizing agent, or oxidant. A simple way to remember the ideas is OIL-RIG, which means oxidation is losing...

cohesion

Water molecules stick to each other through cohesion. Water is neutral overall, but it is a polar molecule. The oxygen atom in one water molecule has a partial negative charge, and it can bind with a hydrogen atom that has a partial positive charge in another water molecule. This forms a hydrogen bond. Each water molecule can form up to four hydrogen bonds with other water molecules, and these bonds give water its cohesive nature. Cohesion helps water form droplets on a surface. Water does not...

adhesion

Water Climbing by Adhesion

Water can climb or stick to surfaces because of adhesion, which is the attraction between different kinds of molecules. In water, this is easy to see on polar surfaces such as glass or cellulose in plants. The positive hydrogen side of water is more attracted to the negative oxygen in silica than to nearby water molecules. This attraction helps explain capillary action. If a narrow glass tube is placed in a beaker of water, water molecules attach to the tube’s surface and the water level rises.

states of water

Water Phase Changes and Ice Density

Water changes between solid, liquid, and gas states as temperature and molecular motion change. In this lesson, the focus is on how water freezes, melts, vaporizes, and returns to liquid or solid form. The balance between intermolecular forces, which pull molecules together, and kinetic energy, which pushes them apart, controls each state. Water freezes when intermolecular forces become stronger than kinetic energy. Unlike most substances, ice is less dense than liquid water. This happens...

specific heat

How Specific Heat Affects Temperature

Specific heat capacity describes how much energy a substance needs to rise by 1 degree Celsius for each gram. It is often written with calories, grams, and degrees Celsius, but it can also be shown in joules, kilograms, and Kelvin. For water, 1 gram needs 1 calorie to increase by 1°C, which is also written as 1 cal/g-°C or 4186 J/kg/K. Water has a high specific heat capacity, so it takes in a large amount of heat before its temperature changes much. It also gives off a lot of heat when it...

vaporization

Vaporization, Boiling, and Evaporation

Vaporization changes a liquid into vapor when temperature adds enough kinetic energy to overcome intermolecular forces. It is a surface phenomenon, which means it starts at the liquid’s surface. The energy needed to vaporize a set amount of liquid at a given pressure and constant temperature is called the heat of vaporization. Water shows this process clearly. When liquid water is vaporized, it becomes steam. One way this happens is boiling, which occurs when vapor bubbles form beneath the...

solvents

Water as a Biological Solvent

Water acts as a biological solvent in many living systems. A solvent is a substance, usually a liquid, that dissolves another substance called a solute. When a solvent and a solute mix, they form a solution, which is a uniform mixture of both parts. Water is called a universal biological solvent because its polar structure helps it dissolve many other polar compounds. Polarity means that one side of the molecule has a slight positive charge and the other side has a slight negative charge.

carbon skeletons

Carbon Backbones in Biomolecules

Carbon backbones give biological molecules their structure and flexibility. Living things are built from macromolecules that contain carbon atoms, and organic compounds are defined by a carbon backbone. Carbon is tetravalent, so each carbon atom can bond with four other atoms. Its valence electrons are stable, so carbon rarely becomes an ion. As carbon chains get longer, they can form ring structures, double bonds, and branching side chains. Carbon-carbon bonds create the carbon skeleton.

key terms and concepts

Learn how water molecules bond through cohesion, create surface tension, form droplets, and help pond skaters walk on water in this high school science topic.

Water Molecules and Surface Tension | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

JoVE Core 시리즈는 생물학의 주요 개념을 설명하는 300개가 넘는 간결하고 이해하기 쉬운 애니메이션 비디오 강의와 오늘날 실험실에서 수행된 실제 연구 실험을 보여주는 150개가 넘는 과학자 활동 비디오를 통해 생물학에 활기를 불어 넣습니다.

Pennsylvania State Academic Standards

Earth and Space Science

3.3.9-12.K

Louisiana Student Standards for Science

High School

Earth Science

Earth’s Systems

HS-ESS2-5

Alabama Course of Study Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

9-12.B.1.4.b

Florida Department of Education

Life Science

SC.912.L.18

SC.912.L.18.12

myJoVE Corporation

Igneous Volcanic Rock

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The Carbon Cycle

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Igneous Intrusive Rock

Source: Laboratory of Alan Lester - University of Colorado Boulder
Igneous rocks are products of the cooling and crystallization of high temperature ...

using-topographic-maps-to-generate-topographic-profiles

Using Topographic Maps to Generate Topographic Profiles

Source: Laboratory of Alan Lester - University of Colorado Boulder
Topographic maps are &#34;plan-view&#34; representations of Earth&#39;s ...

determining-spatial-orientation-rock-layers-with-brunton

Determining Spatial Orientation of Rock Layers with the Brunton Compass

Source: Laboratory of Alan Lester - University of Colorado Boulder
Most rock units exhibit some form of planar surfaces or linear features. Examples ...

Making a Geologic Cross Section

Source: Laboratory of Alan Lester - University of Colorado Boulder
Geologic maps were first made and utilized in Europe, in the mid-to-late 18th century. ...

Use models to explain how mantle convection powers plate tectonics.

ESS.EES.2.1

Analyze and interpret data to predict locations of volcanoes and earthquakes based on plate boundaries.

ESS.EES.2.2

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An Overview of Alkenone Biomarker Analysis for Paleothermometry

Source: Laboratory of Jeff Salacup&#160;- University of Massachusetts Amherst
Throughout this series of videos, natural samples were extracted and ...

Topographic Surveying and Contours

Topographic surveying is critical for documenting the Earth's surface, focusing on capturing elevations, slopes, and natural and man-made features. It is ...

Plotting of Topographic Maps

Topographic maps represent the Earth's surface features using contour lines, which connect points of equal elevation to create a two-dimensional ...

Methods of Obtaining Topography

Topography involves measuring and mapping land elevations, natural features, and artificial structures to create accurate representations of the terrain. ...

Use models to explain how plate tectonics influence topography.

ESS.EES.2.3

The Soil Ecosystem

Plants obtain inorganic minerals and water from the soil, which acts as a natural medium for land plants. The composition and quality of soil depend not ...

Conditions on Early Earth

What are Biogeochemical Cycles?

The most common elements in organic molecules, carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus, are only available in the ecosystem in limited ...

The Water Cycle

The Earth&rsquo;s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, ...

The Nitrogen Cycle

Nitrogen atoms, present in all proteins and DNA, are recycled between abiotic and biotic components of the ecosystem. However, the primary form of ...

The Phosphorus Cycle

Unlike carbon, water, and nitrogen, phosphorus is not present in the atmosphere as a gas. Instead, most phosphorus in the ecosystem exists as compounds, ...

The Sulfur Cycle

Sulfur, an important element in the chemical makeup of proteins, is recycled through the atmosphere and aquatic and terrestrial environments. Found in the ...

Bioremediation

Bioremediation is the use of prokaryotes, fungi, or plants to remove pollutants from the environment. This process has been used to remove harmful toxins ...

Carry out investigations to explain how the rock cycle and rates of weathering, erosion, and soil formation influence Earth's systems.

ESS.EES.2.4

What is Climate?

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What is Weather?

Overview

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Variation of Atmospheric Pressure

Change in atmospheric pressure with height is particularly interesting. The decrease in atmospheric pressure with increasing altitude is due to the ...

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Analyze and interpret data to explain how volcanic activity influences changes in Earth's atmosphere, geosphere, biosphere, and hydrosphere.

ESS.EES.2.5

States of Water

Water exists in any one of the three classical states: solid (ice), liquid (water), and gas (steam or water vapor). The state of water depends on i) the ...

The potential of hydrogen (pH) is a measure of the acidity or basicity of a water-based solution determined by the concentration of hydronium ions (H3O+). ...

Solvents

A solvent is a substance, most often a liquid, that can dissolve other substances. Here, the substance being dissolved is called a solute. When a solvent ...

Redox Reactions

Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another ...

Adhesion

Adhesion occurs when one type of molecule is attracted to a different molecule. Water exhibits adhesive properties in the presence of polar surfaces, such ...

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Specific Heat

The specific heat capacity of a substance refers to the energy required to increase the temperature of one gram of that substance by one degree Celcius. ...

Vaporization

The physical form of a substance changes by changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize ...

Role of Water in Human Biology

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solubility-equilibria-ionic-product-of-water

Solubility Equilibria: Ionic Product of Water

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Carry out investigations to explain the properties of water.

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Mechanism of heat transfer

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Use models to explain how water is an agent of energy transfer.

ESS.EES.3.2

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Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global ...

Analyze and interpret data to explain how major greenhouse gases influence climate.

ESS.EES.3.3

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Water Molecules and Surface Tension

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