Name: energy forms and conservation
Uploaded: 2020-09-03T13:38:25.000Z
Duration: 4 min 10 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Physical Science

Energy

3.2.9-12.Q

What is Energy?

エネルギーは仕事をする 能力として定義されます 仕事とは 加えられた力に反応して 物体が移動する距離と 定義されます 例えば 本を地面から持ち上げて 机の上に置くと 重力の力に逆らって 仕事が行われます エネルギーは主に　ポテンシャルと運動の 2つのタイプに分類されます ポテンシャルエネルギーは 物体の位置や組成 または状態に関連する エネルギーです 安静時エネルギー あるいは保存 エネルギーとして知られています 例えば テーブルの上でに 保持された本は その高さに起因する ポテンシャルエネルギーを持ちます このポテンシャルエネルギーは その位置に保持されている限り 本に蓄積されたままです ポテンシャルエネルギーの 異なる形態としては 重力ポテンシャルエネルギー 電気ポテンシャルエネルギー 化学ポテンシャルエネルギー 核エネルギー 弾性エネルギーなどがあります 重力ポテンシャルエネルギーは ポテンシャルエネルギーの中で 最も明らかな形であり 重力場の影響を受けた 物体の相対的な位置に依存します 例えば テーブルの上に 置かれた本には 重力ポテンシャルエネルギーが 蓄積されています 電位エネルギーは 電荷の引力や反発から来るもので 例えば 電気回路の コンデンサーの中に 蓄えられたエネルギーは 電位エネルギーの形をしています 化学的ポテンシャルエネルギーは 分子に蓄えられたエネルギーです 例えば 乾燥した木材は 化学的ポテンシャルエネルギーを 蓄えていますが これは木材が燃えると放出され 他のエネルギーに変換されます 核エネルギーは 原子核から発生します 弾性エネルギーとは 伸びたパチンコのように その形状によって物体に 蓄えられたエネルギーのことです 運動エネルギーとは 物体の運動に 関連するエネルギーです 例えば 本がテーブルから落ちると その運動により そのポテンシャルエネルギーが 運動エネルギーに変換されます 運動エネルギー自体も 様々な形で存在します 機械的 電気的 熱的エネルギー あるいは放射エネルギーなどです 機械的エネルギーが 動く車のような 物体の機械的な 動きによるものであるのに対し 電気的エネルギーは 落雷に見られるように 電荷の流れによって 構成されています 運動エネルギーが 太陽光のエネルギーのように 電磁波の形をしている場合は 放射エネルギーとなります 熱エネルギーは 物体内の 原子や分子の運動に伴う 運動エネルギーです 物体の中の原子や 分子が素早く動いたり 振動したりして お互いに衝突する回数が増えると 物体の温度が上昇します 燃焼する炎からの熱は 熱エネルギーの一例です これらの原子や分子の 振動や運動が遅くなると 逆のことが起こります その場合 水が凍るときのように 対象物が冷たいと 熱エネルギーが低いと言われます これらすべての異なる形態は ある種類から別の種類へ またはある物体から別の物体への エネルギーの流れを促進して 仕事を完了させることを 可能にします エネルギー保存の法則では エネルギーは 創造されることも 破壊されることもなく ある種類のものから別のものへと 変化するだけだとされており システムの総エネルギーは 保存されたままです 例えばアーチェリーでは 伸びた弓に保持された矢には 弾性ポテンシャルエネルギーが 含まれています 弓が解放されると この潜在的なエネルギーは 矢の運動エネルギーに変換され 矢は標的に向かって 飛んでいきます ここでも 全体のエネルギーは 保存されたままです

エネルギーとは？

宇宙はさまざまな形態の物質で構成されており、あらゆる形態の物質にエネルギーが含まれています。  地球上のさまざまなエネルギーは、究極のエネルギー源である太陽に由来します。 植物は太陽から光エネルギーを取り込み、光合成の過程を通じて化学エネルギーに変換します。 この植物に貯えられたエネルギーは多くの方法で活用することができます。 例えば、食品として植物を食べることで、身体にエネルギーを供給し、木材や石炭（化石化された植物）を燃やすことで、熱と電気を発生させます。 したがって、物質のすべての変化はすべてエネルギー変化を伴うため、エネルギーがどのようにある形態から別の形態へ流れているかを理解することが重要です。  
 
 エネルギーは仕事をする能力と定義されています。 仕事は、物体に力を加えると、物体が対抗する力を超えたことで物体が動いた場合に発生します。 たとえば、机が床の抵抗を超えて部屋を横切るように押されたときに、仕事が発生します。  
 
 エネルギーは、位置エネルギーと運動エネルギーという2 つの主要なタイプにグループ化できます。 位置エネルギーとは、物体の相対位置、組成、または条件に関連するエネルギーです。 運動エネルギーは、物体の運動に関連するエネルギーです。 例えば、ダムにある水は、地面から高い位置にあるためにエネルギーが発生する可能性があります。 水が発電機を通して下方向に流れると運動エネルギーが得られ、水力発電所で発電するための仕事をすることができます。 
 
 <h4>位置エネルギー </h4>
 
 位置エネルギーは、静止エネルギーまたは蓄積エネルギーとしても知られています。 一般的な位置エネルギーには、木からぶら下がっているリンゴに蓄えられた重力の位置エネルギー、 電荷の引力や斥力によって物体に蓄えられた電気的な位置エネルギー、原子と分子の結合部に蓄えられた化学的な位置エネルギーなどがあります。 また、原子核に蓄えられた核エネルギーと、その形状によって伸縮ばねに蓄えられた弾性エネルギーも、位置エネルギーの一種です。 
 
 通常、エネルギーが高い物体やシステムは安定性が低くなるため、安定性を確保するためにエネルギーレベルが低いほうへと動く傾向があります。 例えば、放射性元素ウラン 235 （ U235 ）には不安定な核があります。 安定性を確保するため、小型で安定した元素に分裂し、蓄積された核エネルギーを放出します。 この放出されたエネルギーは、原子力発電所での発電に使用されます。  
 
 <h4>運動エネルギー </h4>
 
 物体の運動エネルギーの量は、その質量と速度によって異なります。 同じ速度で傾斜した平面を転がる、異なる質量の 2 つのボールを考えてください。 より重い球により多くの運動エネルギーがあります。 同様に、同じ質量の 2 つのボールが異なる速度で傾斜した平面を転がると、より速く動くボールのほうがより多くの運動エネルギーを持ちます。  
 
 異なる運動エネルギーの形態として力学的、電気的、放射性、音、 熱エネルギーがあります。 力学的エネルギーは、物体の動きに関連しています。 物体の移動が速いほど、力学的エネルギーが多くなります。  たとえば、銃やダムを流れる水から発射される弾丸は、力学的エネルギーの例です。 電気エネルギーは電荷の流れに起因し、雷雨のときの落雷や、日常にある電気回路や電子機器に見られます。 放射エネルギーも運動エネルギーの一種で、電磁波として伝送され、光と熱の形で体感できます。 太陽光が放射エネルギーの一例です。 
 
 熱エネルギーは原子と分子のランダムな動きに関連しています。 物体の原子や分子がすばやく動いたり振動したりすると、その原子や分子は運動エネルギー（ KE ）の平均が高くなり、その物体は「高温」と呼ばれます。 原子と分子がゆっくりと動いているときは、平均 KE が低く、物体は「低音」と示されます。 したがって、物体の温度変化によって熱エネルギーを観測することができます。 化学反応や相変化（融解や気化など）が発生しないと仮定すると、物質試料中の熱エネルギー量が増加すると、温度が上昇します。 同様に、化学反応や相変化（凝縮や凍結など）が発生しないと仮定すると、物質試料の熱エネルギー量が減少すると、温度が低下します。 
 
 <h4>エネルギー保存法則 </h4>
 
 エネルギーは、ある形から別の形に変換できるが、変化する前に存在していた総エネルギーは、変化後も常に何らかの形で存在します。 この観測は、エネルギー保存法則として表現されています。 エネルギー保存法則は、エネルギーの形が変わることはあっても、エネルギーの発生や破壊はないと規定しています。 したがって、システムの総エネルギーは一定のままです。 たとえば、化学エネルギー ( 位置エネルギーの一種 ) は、ガソリンを構成する分子に保存されています。自動車のエンジンのシリンダ内でガソリンが燃焼すると、化学反応で急速に膨張したガス状の生成物が、シリンダのピストンを動かすことで力学的エネルギー（運動エネルギーの一種）を発生させます。 
 
 このテキストは <a href=https://openstax.org/books/chemistry-2e/pages/5-1-energy-basics">、 Openstax, Chemistry 2e, Section 5.1: Energy Basics から引用しています。</a>

宇宙はさまざまな形の物質で構成されており、すべての形の物質にはエネルギーが含まれています。 地球上のさまざまな形態のエネルギーは、...

Education

JoVE Core

Chemistry

化学

Introduction: Matter and Measurement

序論：物質と測定

KEY TERMS AND CONCEPTS

主要用語と概念

energy forms and conservation

Energy is a property of matter that appears in many forms. On Earth, most energy starts with the Sun. Plants capture light energy from the Sun and use photosynthesis to turn it into chemical energy. That stored energy can then move through living things and materials in several ways. People get energy from plant foods, and wood or coal, which come from fossilized plants, can be burned to produce heat and electricity.

Energy is defined as the ability to do work. Work happens when a force moves an object against a resisting force. Pushing a table across a room against the floor is one example. To understand changes in matter, it helps to track how energy changes from one form to another.

Energy is often grouped into two main types: potential energy and kinetic energy. Potential energy is stored energy linked to an object’s position, composition, or condition. Kinetic energy is the energy of motion. Water held behind a dam has potential energy because of its height. When it flows downward through generators, it gains kinetic energy and can help produce electricity in a hydroelectric power plant.

Potential energy is sometimes called energy at rest. It includes gravitational potential energy, such as an apple hanging from a tree, electrical potential energy from the attraction or repulsion of charges, and chemical potential energy stored in bonds between atoms and molecules. It also includes nuclear energy in an atomic nucleus and elastic energy in a stretched spring. In general, systems with high potential energy are less stable and tend to move toward lower energy states. Uranium-235 is one example. Its unstable nucleus splits into smaller, more stable elements and releases stored nuclear energy that can be used in nuclear power plants.

The amount of kinetic energy depends on mass and speed. If two balls move at the same speed, the heavier ball has more kinetic energy. If two balls have the same mass, the faster one has more kinetic energy. Kinetic energy includes mechanical, electrical, radiant, sound, and thermal energy. Mechanical energy is tied to motion, like a bullet fired from a gun or water moving down a dam. Electrical energy comes from the flow of electric charges, such as lightning or electricity in circuits. Radiant energy travels as electromagnetic waves and includes sunlight. Thermal energy comes from the random motion of atoms and molecules, so faster motion means higher average kinetic energy and a hotter object. Slower motion means lower average kinetic energy and a colder object. If no chemical reaction or phase change happens, adding thermal energy raises temperature, and removing it lowers temperature.

Energy can change form, but it is not created or destroyed. This is the Law of Conservation of Energy. The total energy in a system stays constant even when energy is converted from one form to another. Gasoline shows this change clearly. It stores chemical energy, which is a type of potential energy. When gasoline burns in a car engine, the reaction produces gases that move the pistons and create mechanical energy, which is a type of kinetic energy.

Energy Forms and Conservation

scientific laws and theories

How Science Explains Laws and Theories

Scientific laws and scientific theories describe science in two different ways. A law is a concise verbal or mathematical statement that summarizes many experimental observations. It describes or predicts aspects of the natural world that stay the same under the same conditions. A scientific theory is different because it explains why natural events happen. It is a unifying principle that gives a well-supported and testable explanation for a broad set of observations. Strong theories are the...

the scientific method

How Scientists Test a Hypothesis

Chemistry uses the scientific method to turn observations into testable answers. Scientists begin by observing a phenomenon in the physical world and then asking a question about it. This process helps explain everyday chemistry through evidence. A question leads to a hypothesis, which is a tentative explanation for what is being observed. Scientists often use earlier research and published literature to shape that idea. A strong hypothesis must be testable, meaning it can be supported by...

physical and chemical properties of matter

physical-and-chemical-properties-of-matter

Distinguishing Physical and Chemical Changes

Matter can be identified by its properties, which are the features that help us tell one substance from another. These properties fall into two main groups: physical properties and chemical properties. Understanding the difference helps explain how matter changes. A physical property is a feature of matter that is not linked to a change in chemical composition. Examples include density, color, hardness, melting point, boiling point, and electrical conductivity. Some physical properties can be...

what is energy?

Energy is a property of matter that appears in many forms. On Earth, most energy starts with the Sun. Plants capture light energy from the Sun and use photosynthesis to turn it into chemical energy. That stored energy can then move through living things and materials in several ways. People get energy from plant foods, and wood or coal, which come from fossilized plants, can be burned to produce heat and electricity. Energy is defined as the ability to do work. Work happens when a force moves...

classifying matter by state

States of Matter and Their Properties

States of matter help describe how matter behaves in chemistry. Matter is anything that has mass and takes up space. It is found everywhere, including air, water, soil, mountains, and even our bodies. The three common states on Earth are solid, liquid, and gas. A solid has a definite shape and a definite volume. Its particles, such as atoms or molecules, are packed very closely together and held in place by strong forces, so they only vibrate slightly. This tight arrangement makes solids...

measurement: standard units

Measurement: SI Units and Conversions

Measurement gives three kinds of information: a number, a unit, and an estimate of uncertainty. The number shows size or magnitude. The unit gives a standard for comparison. The uncertainty reflects possible error in the measurement. Numbers can be written in more than one way. A value may appear in decimal form or in scientific notation, which is also called exponential notation. For example, the maximum take-off weight of a Boeing 777-200ER airliner is 298,000 kilograms, or 2.98 × 10^5 kg. <br...

classifying matter by composition

Matter: Elements, Compounds, and Mixtures

Matter can be grouped by composition into pure substances and mixtures. A pure substance has a constant composition throughout and uniform properties. For example, any sample of sucrose has the same composition and the same physical properties, such as melting point, color, and sweetness, no matter where it is isolated from. A mixture contains two or more kinds of matter in varying amounts. Its parts can be separated by physical changes, such as evaporation. The components keep their own...

measurement: derived units

SI Units, Density, and Property Types

SI units and derived units help describe physical properties in chemistry. The International System of Units, or SI system, uses agreed-upon base units for seven fundamental properties: length, mass, time, temperature, electric current, amount of substance, and luminosity. Units made by combining these base units are called SI-derived units. Speed is one example. If distance is measured in meters and time in seconds, the derived unit for speed is meters per second, or m/s. Miles per hour is...

dimensional analysis

Using Conversion Factors to Cancel Units

Dimensional analysis is a method for using conversion factors to cancel units and solve measurement problems. It is also called the factor label method. The main rule is that units must be treated the same way as the numbers attached to them. A conversion factor is a ratio of two equal quantities written in different units. For example, 1 meter is equal to 1.0936 yards. That relationship can be used to build a factor that converts one unit into the other. When a value is multiplied or divided...

uncertainty in measurement: accuracy and precision

uncertainty-in-measurement-accuracy-and-precision

Measurement Error: Reading Results Correctly

Measurement error affects how scientists judge the quality of their results. Repeated measurements help show whether results are precise and accurate. A measurement is precise when repeated values are very similar. A measurement is accurate when it is very close to the true or accepted value. Precise values agree with each other, while accurate values agree with the true value. A pharmaceutical quality control chemist can use this idea to check machines that dispense 500 mL of cough syrup. The...

uncertainty in measurement: reading instruments

uncertainty-in-measurement-reading-instruments

Measurement Uncertainty and Significant Figures

Measurement uncertainty and significant figures show how carefully a value can be read from an instrument. Counting is different. If the number of objects does not change during counting, the result is exact. Defined quantities are exact too. For example, 1 foot is exactly 12 inches, 1 inch is exactly 2.54 centimeters, and 1 gram is exactly 0.001 kilograms. Most other measurements are not exact because the measuring process has limits. The result depends on the device used and on the person...

uncertainty in measurement: significant figures

uncertainty-in-measurement-significant-figures

Significant Figures and Rounding Rules

Significant figures and rounding rules help students report measurements with the right level of certainty. A measurement includes every digit that was actually measured, including the last uncertain digit. That is why a value can look simple but still carry useful information about the tool used to measure it. Zero can also be significant when it is part of a measured value. For example, if a scale reads 140 pounds to the nearest pound, the 1, 4, and 0 are all significant. Reporting...

key terms and concepts

Explore how energy moves from the Sun to plants, how potential and kinetic energy work, and why the law of conservation of energy matters.

Energy Forms and Conservation | JoVE K12

chemistry

JoVE Core 化学は、簡潔で理解しやすいアニメーションビデオレッスンを使用して、一般的な化学の概念を生き生きとしたものにします。さらに、活動する科学者のビデオでは、現在世界中の実験室で行われている古典的そして独創的な研究・実験をお見せします。

3.2.9-12.R

Life Science

matter-and-energy-in-organisms-and-ecosystems

Matter and Energy in Organisms and Ecosystems

3.1.9-12.F

Louisiana Student Standards for Science

High School

HS-PS3-3

HS-PS3-4

Life Sciences

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

From Molecules To Organisms: Structures And Processes

HS-LS1-7

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Study Of Matter

Classification of matter

Tennessee Academic Standards

Physics

PHYS.PS3.2

PHYS.PS3.3

CHEM1.PS3.4

Virginia  Standards of Learning

HIgh School

CH.7

CH.7.a

Arizona Science Standards

Earth and Space Science

HS.E1

HS.E1U1.12

HS.E1U1.13

HS+Phy.P4

HS+Phy.P4U1.6

HS.P4

HS.P4U3.9

Alabama Course of Study Science

9-12.PS.1.1

Matter and Its Interactions

9-12.PS.3.4.h

Earth's Place in the Universe

9-12.ESS.1.1

Next Generation Science Standards

Florida Department of Education

SC.912.E.7

SC.912.E.7.1

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

C-PS3-4

P-PS3-1

P-PS3-2

P-PS3-3

Georgia Standards of Excellence

SPS7.

Types of Energy

The universe is composed of matter in different forms, and all forms of matter contain energy.&#160; The different forms of energy on Earth originate from ...

Energy Basics

Chemical reactions, such as those that occur when you light a match, involve changes in energy as well as matter.

Chemical changes and their accompanying ...

Conservation of Mechanical Energy

The mechanical energy E of a system is the sum of its potential energy U and the kinetic energy K of the objects within it. What happens to this ...

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Conservation of Energy

The terms &#39;conserved quantity&#39;&#160;and &#39;conservation law&#39;&#160;have specific scientific meanings in physics, which differ from the ...

Conservation of Energy: Application

When solving problems using the energy conservation law, the object (system) to be studied should first be identified. Often, in applications of energy ...

Students who demonstrate understanding can create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known. Clarifying Statement: Emphasis is on explaining the meaning of mathematical expressions used in the model. Assessment Boundry: Assessment is limited to basic algebraic expressions or computations; to systems of two or three components; and to thermal energy. kinetic energy, and/or the energies in gravitational, magnetic, or electric fields.

3.2.9-12.O

Types of Potential Energy

Potential energy is also known as energy at rest or stored energy. Common types of potential energy include the gravitational potential energy stored in ...

Types of Kinetic Energy

The amount of kinetic energy of an object depends on its mass and speed. Consider two balls of different masses rolling down an inclined plane at the same ...

Kinetic Energy - I

It&#8217;s plausible to suppose that the greater the velocity of a body, the greater effect it could have on other bodies. This does not depend on the ...

Kinetic Energy - II

The kinetic energy of a particle is one-half of the product of the particle&#8217;s mass and the square of its speed. Note that just as Newton&#8217;s ...

Gravitational Potential Energy

Potential energy is not just a property of each object, but also a property of the interactions between objects in a chosen system. For each type of ...

Elastic Potential Energy

Elastic potential energy is the energy stored as a result of the deformation of an elastic object, such as the stretching of a spring. An object is ...

Energy in Simple Harmonic Motion

To determine the energy of a simple harmonic oscillator, consider all the forms of energy it can have during its simple harmonic motion. According to ...

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problem-solving-energy-in-simple-harmonic-motion

Problem Solving: Energy in Simple Harmonic Motion

Simple harmonic motion (SHM) is a type of periodic motion in time and position, in which an object oscillates back and forth around an equilibrium ...

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Kinetic and Potential Energy of a Wave

All forms of waves carry energy; this is directly visualized in nature. For instance, the waves of earthquakes are so intense that they can shake huge ...

Energy and Power of a Wave

The total energy associated with a wavelength is the sum of the potential energy and the kinetic energy. The average rate of energy transfer associated ...

Energy Carried By Electromagnetic Waves

Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes, this energy is obvious, such as in the summer sun&#39;s ...

Students who demonstrate understanding can develop and use models to illustrate that energy at the macroscopic scale can be accounted for as a combination of energy associated with the motions of particles (objects) and energy associated with the relative positions of particles (objects). Clarifying Statement: Examples of phenomena at the macroscopic scale could include the conversion of kinetic energy to thermal energy, the energy stored due to position of an object above the earth, and the energy stored between two electrically-charged plates. Examples of models could include diagrams, drawings, descriptions, and computer simulations. Assessment Boundry: N/A

3.2.9-12.P

The universe is composed of matter in different forms, and all forms of matter contain energy. &#xA0;The different forms of energy on Earth originate from ...

Energy Transfer in Chemical Reactions

Chemical reactions require sufficient energy to cause the matter to collide with enough precision and force that old chemical bonds can be broken and new ...

Students who demonstrate understanding can design, build and refine a device that works within given constraints to convert one form of energy into another form of energy. Clarifying Statement: Emphasis is on both qualitative and quantitative evaluations of devices. Examples of devices could include Rube Goldberg devices, wind turbines, solar cells, solar ovens, and generators. Examples of constraints could include use of renewable energy forms and efficiency. Assessment Boundry: Assessment for quantitative evaluations is limited to total output for a given input. Assessment is limited to devices constructed with materials provided to students.

Students who demonstrate understanding can plan and conduct an investigation to provide evidence that the transfer of thermal energy when two components of different temperature are combined within a closed system results in a more uniform energy distribution among the components in the system (second law of thermodynamics). Clarifying Statement: Emphasis is on analyzing data from student investigations and using mathematical thinking to describe the energy changes both quantitatively and conceptually. Examples of investigations could include mixing liquids at different initial temperatures or adding objects at different temperatures to water. Assessment Boundry: Assessment is limited to investigations based on materials and tools provided to students.

force-and-potential-energy-in-one-dimension

Force and Potential Energy in One Dimension

Force can be calculated from the expression for potential energy, which is a function of position. The component of a conservative force, in a particular ...

force-and-potential-energy-in-three-dimensions

Force and Potential Energy in Three Dimensions

Consider a particle moving under the action of a conservative force that has components along each coordinate axis. Each component of force is a function ...

Energy Diagrams - I

The dynamics of a mechanical system can be easily understood by interpreting a potential energy diagram. Since energy is a scalar quantity, the ...

Energy Diagrams - II

Energy diagrams are important to understand the dynamics of a system. The topology of an energy diagram helps illustrate the equilibrium points of the ...

Students who demonstrate understanding can develop and use a model of two objects interacting through electric or magnetic fields to illustrate the forces between objects and the changes in energy of the objects due to the interaction. Clarifying Statement: Examples of models could include drawings, diagrams, and texts, such as drawings of what happens when two charges of opposite polarity are near each other. Assessment Boundry: Assessment is limited to systems containing two objects.

3.2.9-12.S

Energy Forms and Conservation

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