ENERGY Part One Basics and Definitions Energy is

ENERGY!!!

Part One: Basics and Definitions

Energy is… • Energy is the ability to do work. • Work is movement. Energy is expended to move objects from one place to another. • Forces acts on things (matter) to create energy (movement).

How is energy measured? • The scientific unit for energy is the Joule (J) • One joule is defined as the amount of energy used when one Newton of force moves an object 1 meter. • Energy = Force applied (N) x distance moved (m).

How is energy measured? • If it takes 50 Newtons (N) to move an object 20 meters (m), then 1000 Joules (J) of energy were used. • 50 N x 20 m = 1000 J

How is energy measured? • Energy can also be measured in Calories. • 1 food Calorie = 4184 Joules

Is one Joule a lot of energy? • A typical candy bar has about 1 000 Joules of energy in it. • A stick of dynamite has about 2 100 000 Joules of energy in it. • That means that two 240 calorie candy bars have as

Gummy Bear Sacrifice!!!

Part Two: The Law of Conservation of Energy

The law of conservation of energy • Energy cannot be created or destroyed!! • The amount of energy in the universe is constant (we’re pretty sure…) • Energy can change form from one type of energy to another.

The six types of energy • • • Mechanical Energy Chemical Energy Thermal Energy Electrical Energy Electromagnetic Energy Nuclear Energy

Example of energy changing form: • The chemical energy from gasoline in a car transforms into mechanical energy (the movement of the pistons in the engine) and thermal energy (the heat caused by friction in the engine block).

More examples of energy conversion can be found at the end of this presentation.

Part Three: Mechanical Energy

Mechanical Energy • Mechanical energy is associated with the motion and position of objects. • Mechanical energy is broken into two categories: • Kinetic Energy = Energy of moving things • Potential Energy = Movement stored as a result of position.

Total Mechanical Energy is the sum of Kinetic Energy and Potential Energy ME = PE + KE

Kinetic Energy • Can be calculated if you know an object’s mass in kilograms (kg) and its velocity in meters per second (m/s). • KE = ½ mv 2

Kinetic Energy • A one ton truck travels at 60 miles per hour. How much kinetic energy does it have? • First convert units to metric. • A 1000 kg pickup truck travels at 27 m/s. • KE = ½ x 1000 x 272 • KE = 364 500 Joules

Potential Energy • Potential energy is stored movement. • Movement can be stored as a result of shape or position.

Potential Energy • Examples: • A rock on a high cliff can fall. • A stretched spring or rubber band can snap back.

Gravitational Potential Energy • PE stored in objects as a result of their height off the ground can be measured if you know the objects Mass in kilograms (kg), its Height off the ground in meters (m), and the Acceleration due to gravity (9. 8 m/s 2) • Gravitational PE = mgh

Gravitational Potential Energy • A 1000 kg truck drives off a 50 meter cliff. How much potential energy does it have the moment it leaves the cliff? • PE = 1000 kg x 50 m x 9. 8 m/s 2 • PE = 490 000 Joules

Potential Energy turns into Kinetic Energy. • As the weight falls its potential energy is converted into kinetic energy. • Before it falls 100% of the mechanical energy is PE. • The moment before impact 100% of the mechanical energy has been converted to KE

Practice using the KE and PE equations to solve the following problem

Assume this is a frictionless Environment.

Mechanical Waves. • Mechanical Energy can move from place to place as a mechanical wave. • Mechanical waves require matter to move through. We call the matter a Medium.

Mechanical Waves. • The matter that carries a mechanical wave is called a medium. • Examples of different mediums: • Air • Water • Earth

Types of Mechanical Waves • Longitudinal Wave: Particles in medium move parallel to the direction of wave motion. Example: Sound waves, and earthquake primary waves. • Like a Slinky.

Types of Mechanical Waves • Transverse Wave: particles in wave move perpendicular to the direction of movement. Example: Earthquake secondary waves. • Like a Jump rope.

The following link may help you to understand the difference between wave types: Types of Waves

Parts of a Wave:

Parts of a Wave: • Wavelength – The shorter the wavelength, the more energy the wave delivers per second. • Amplitude – The bigger the amplitude the more energy the wave has.

Part Four: Thermal Energy

Thermal Energy • Thermal Energy is the vibration of particles in a substance. • Temperature is a measurement of average kinetic energy of the particles in a substance.

Particles of Hot air move faster than particles of Cold air.

Temperature and State of Matter • The hotter a substance is, the faster its particles move. • Eventually the particles in a solid substance vibrate so much that the substance liquefies. • If the liquid particles continue to heat up, they will eventually have enough speed to fly away and evaporate

• Gas particles are moving too fast to stick together. • Particles in a liquid are rolling over each other and mixing. They still have too much kinetic energy to form a uniform structure. • Particles in a solid still vibrate, but their order remains consistent

Thermal Energy Transfer. • Thermal energy flows from warmer areas to colder ones.

Thermal Energy Transfer • Convection – Mass movement of particles in a fluid (like air, water, or magma) when the hot areas of the fluid rise above the cooler ones. • Conduction – Through objects in contact. Vibration of the particles in one substance transfers to the other substance. (Like when energy is transferred between billiard balls) • Radiation – Hot particles can lose kinetic energy by turning it into Infrared Radiation. When this happens the ‘heat’ is no longer

Conduction – Vibration of one particle is passed to the next particle.

Convection – Hot fluid rises, cool fluid falls.

Radiation – Vibrations of particles give off Electromagnetic Energy in the form of Infrared Radiation. This heat is no longer moving particles. It has turned into a type of light.

Infrared Radiation can be seen with special cameras.

Part Five: Electrical Energy

Electrical Energy • A form of energy resulting from the flow of charged particles, such as electrons or protons.

Electrical Energy • Particles flow because of the attraction between positive and negative charges. • When positively and negatively charged particles are separated, they are attracted to each other. • If they have a way to get to each other they will flow.

These batteries have charges separated from one another. When connected by a wire the charges flow until they can reach other and become neutral

Electricity Vocabulary • Current • Voltage • Resistance

Current (I) • Electric current is a flow of electric charge through a conductor (usually a wire). • This charge is typically carried by moving electrons, but any flow of charged particles (protons, ions, or electrons) is considered an electrical current.

Voltage (V) • Voltage is the potential to develop a current through a conductor (like a wire). • The higher the voltage, the bigger the maximum current that can be pushed through a wire. • Example: A 9 V battery can deliver bigger current than a 1. 5 V battery.

Resistance (R) • Electrical resistance is the opposition to the passage of an electric current through an object. • Refers to how well something conducts. • Metal conducts electricity well and has low resistance. Rubber doesn’t conduct electricity because it has a high resistance.

Ohm’s Law • Ohm’s law describes the mathematical relationship between Voltage (V), Current (I), and Resistance (R). • V = IR

• This analogy helps explain the relationships in Ohm’s Law. V = IR • The water tank represents Voltage, how much water is available to flow. • The tap represents Resistance because it keeps the water from flowing out all at once. Only so much water is allowed through. • The stream of water represents the Current.

Circuits • An electrical circuit is a closed loop giving a return path for the current. • In the case of a battery, electrons flow from the negative node to the positive one. • There are three types of basic circuit. • Simple • Series • Parallel

Simple Circuit • A simple circuit allows electrons to flow from one side of the battery to the other. • The electrons flow through the bulb and some of the electrical energy is converted to light (electromagnetic energy) and heat (thermal energy).

Series Circuit • Circuits in series lose voltage through each component. • These bulbs will both be dim because the same current must light both bulbs.

Parallel Circuits • Circuits in parallel don’t lose voltage through each component. • These bulbs will both be bright because they have their own separate current.

Electricity Generation • Where does our electricity come from? • Our household electricity is produced by changing other types of energy into electrical energy. • This is called an energy

Example of converting energy into electricity: • Coal (Chemical Energy) gets burned Heat (Thermal Energy) boils water Steam turns a turbine (Mechanical Energy) Turbine runs a generator. Generators turn mechanical energy into electricity (Electrical Energy).

Want some extra credit? Build a simple generator! Ask me how ; -)

Problems with Power Production • All methods of power generation have disadvantages. • Generally producing electricity is either expensive, dirty, dangerous, non-renewable, or it destroys the environment.

Part Six: Nuclear Energy

Einstein and Nuclear Energy • Albert Einstein figured out that all matter contains unexpectedly HUGE!? ! amounts of energy!! • E = mc 2 • Energy (E) equals mass (m) multiplied by the speed of light (c) squared.

Einstein and Nuclear Energy • His discovery was so shocking because no one had ever seen matter yield this much energy. • Our biggest bombs at the time could only release tiny amounts of energy compared to what Einstein predicted could be released.

Einstein and Nuclear Energy • If we burned 3 kilograms of gasoline (about 1. 05 US Gallons or 3. 97 liters), it would yield 140, 000 Joules. • This is a lot of energy but burning something only releases the CHEMICAL ENERGY. • There is still a HUGE amount of energy trapped in the nuclei of the gasoline atoms. • Energy trapped inside the nucleus of an atom is called NUCLEAR ENERGY

Einstein and Nuclear Energy • If we took that same 3 kilograms of gasoline and broke open every single atom in it we would release 2. 7 x 1017 Joules of energy! • This is almost 2 billion times the energy we obtained from the "ordinary" burning of one gallon of gasoline!

The Basic Atom Lots of energy inside!!

Basic Atom Vocabulary • Nucleus - The very dense region, consisting protons and neutrons, at the center of an atom. • Proton - A subatomic particle in the nucleus with a positive (+1) electric charge. • Neutron – A subatomic particle in the nucleus with no charge (+0). (It is neutral) • Electron – A subatomic particle outside of the nucleus with a negative (-1) charge.

Basic Atom Vocabulary • Atomic Number – The number of protons in the nucleus of an atom. • Atomic Mass – The number of protons + neutrons in the nucleus of an atom.

Nuclear Energy • Nuclear energy is stored inside the nuclei of atoms.

The Basic Atom Lots of energy inside!!

Nuclear Energy • Nuclear energy can be released in two ways: • Nuclear Fission • Nuclear Fusion

Nuclear Fission • Nuclear fission means: To split the nucleus. • Nuclei are very difficult to split. • Splitting a nucleus can be accomplished by shooting it with radiation (like in a nuclear bomb), or crashing it into another nucleus at very high speed (like in a particle accelerator).

Fission in a nuclear reactor:

Nuclear Fusion • Nuclear fusion means: To combine two nuclei into one. • Positively charged Nuclei repel each other. • Forcing two nuclei to combine takes A LOT of force. (like the pressure inside a star)

Nuclear Fusion in a Star: • A Star is a massive ball of Hydrogen being crushed by gravity. • Eventually the pressure in the center of a star is so great that Hydrogen (H) atoms begin to fuse together to form Helium (He). • Nuclear fusion in a star is what creates the all of the energy that a star releases.

Balanced forces in a Star:

Part Seven: Electromagnetic Energy

Electromagnetic (EM) Energy • Waves of electrical and magnetic energy moving together through space at light speed. • Also called electromagnetic radiation.

Types of Electromagnetic Waves • • Radio Waves Microwaves Infrared Light Visible Light Ultraviolet Light X-rays Gamma Rays

Electromagnetic Waves vs. Mechanical Waves Mechanical Wave Electromagnetic Requires medium to travel Can travel in a vacuum Can have many frequencies, amplitudes, and speeds. Can have many frequencies & amplitudes. Only one speed: 3. 00 x 108 m/s Created from vibrations of electrons Just keeps going forever Created from vibrations of large masses Lose energy as they travel

Parts of an Electromagnetic Wave:

Parts of an Electromagnetic Wave: • Wavelength and Frequency – The higher the frequency the more energy the wave delivers per second. • Amplitude – The bigger the amplitude the more energy the wave has.

A prism can be used to bend different wavelengths of colored light found in ‘white light, ’ which isn’t really white. Really it’s all the colors mixed together.

Electromagnetic Waves. • We can see visible light with our eyes, but most of the wavelengths in the electromagnetic spectrum are invisible to us. • There is a whole world of light surrounding us that we cannot detect with the naked eye. • Just ask Sir Frederick William Herschel how he discovered Infrared ; -)

Bug’s-Eye View of a Narcissus Visible Light Ultraviolet Light

Scientists use special cameras to see different wavelengths of EM radiation. • This is what the sun would look like if you could see (top left to bottom right) X-rays, Ultraviolet Light, Infrared Light, and Radio Waves.

Looking at different types of EM radiation tells us a lot about what’s happening in deep space. • Take the following example of ‘The Crab Nebula’ • The Crab Nebula is the remnant of a supernova explosion that was seen on Earth in 1054 AD. It is 6000 light years from Earth.

Crab Nebula in Visible Light

This picture of The Crab Nebula in Ultraviolet light shows us where majority of the energy is.

When seen in X-ray the structure of the Crab Nebula Comes into focus. At the center of the bright nebula is a rapidly spinning neutron star, or pulsar that emits pulses of radiation 30 times a second!!

Part Eight: Chemical Energy

Chemical Energy • Chemical Energy is stored in the chemical bonds between atoms. CH 4 H 2 O NH 3

Chemical energy in chemical bonds • Multiple atoms can bond together into larger molecules. • It takes energy to form these chemical bonds. • Breaking chemical bonds releases the trapped energy.

Chemical Energy vs. Nuclear Energy Chemical Energy Stored inside the nucleus of an atom. Stored in bonds between atoms. Holds the nucleus of an Holds multiple atoms atom together.

Chemical energy and combustion. • A good way to release the chemical energy in something is to burn it. • When a substance is burned chemical bonds in the molecule are broken and the energy comes out in the form of heat and light.

One molecule of propane can be burned with five molecules of oxygen creating three molecules of carbon dioxide and four water molecules.

Chemical energy is trapped in the bonds holding propane together. When it burns all of these bonds are broken, releasing energy.

Chemical Energy and You • You get your energy from burning a high-energy molecule called ‘Glucose. ’ • Glucose is a large molecule with many chemical bonds. • Glucose: C 6 H 12 O 6

Look at all those Chemical bonds!! Glucose!

The law of conservation of energy • Energy cannot be created or destroyed!! • The amount of energy in the universe is constant (we’re pretty sure…) • Energy can change form from one type of energy to another.

Energy Conversions!

Can you identify the energy conversion pictured? In this example chemical energy in fireworks is transformed into light (electromagnetic energy).

• Chemical (Rocket Fuel) Thermal Energy (Heat) + Electromagnetic Energy (Light) + Mechanical Energy (Flying Rocket).

• Mechanical energy • Potential Energy (PE) Kinetic Energy (KE) + Sound (mechanical wave).

• Electrical Mechanical Energy (sound waves are mechanical waves)

• Chemical Energy (in the riders food) Mechanical + Thermal Energy

• Nuclear Heat + Light + Sound Energy.

• Mechanical Energy (PE stored in water at the top of a hill) Mechanical Energy (KE of falling water transfers to the spinning turbine) Electrical Energy.

• Electromagnetic Energy Chemical Energy. • Plants use light to build chemical bonds in glucose.

• Chemical (gasoline) Mechanical Energy.

Can you think of any other types of energy that can be converted?