Vocabulary Energy Wave Amplitude Conduction Convection Radiation Color spectrum Wavelength Potential energy Kinetic energy Light energy Chemical energy Mechanical energy
What is Energy? Energy is defined as the ability to do work Work is using energy to move something
What are Waves? A wave is a disturbance that transfers energy from place to place. Most waves need a medium or substance to travel through Gas, liquids & solids can all be mediums Moving objects have energy. A moving object can transfer energy to a medium, producing waves.
Mechanical Waves Waves that REQUIRE a medium through which to travel are called mechanical waves. Mechanical waves do not carry the medium they travel through with them Waves on the ocean do not move the water molecules with them Molecules stay in place, just bob up and down transferring the energy onward Mechanical waves are produced when an energy source causes a medium to vibrate
Types of Waves Mechanical waves are classified by how they move through a medium. Two types of Mechanical Waves Transverse waves Longitudinal waves
Transverse Waves Transverse waves move the medium at a right angle to the direction of the wave Moving a rope up and down, crests & troughs
Longitudinal Waves Longitudinal waves move the medium parallel to the direction in which the waves travel Like a slinky being pushed back and forth Compressions: when the coils or waves are close together Rarefactions: when the coils or waves are farther apart. Example: Sound
Properties of Waves Foldable Fold your paper into 4 sections Label sections speed, amplitude, frequency, and wavelength In each section write: Definition How you measure it in longitudinal and transverse waves 3 facts On the back, draw and label an example of each wave
Waves Wavelength Amplitude Frequency Speed The energy of a wave depends on the wavelength
Wavelength A wave travels a certain distance before it starts to repeat its motion Wavelength is the distance between two parts of a wave Crest to crest Trough to trough
Amplitude Amplitude is the rise of a wave from the rest position Rest position The more energy a wave has, the greater the amplitude.
Amplitude Amplitude of transverse waves: the maximum distance a wave moves up or down Amplitude of longitudinal waves: measurement of how compressed, or rarefied, the waves are. Dense compressions means it has a large amplitude
Frequency Number of complete waves that pass a given point in a certain amount of time. If one wave passes by every second, the frequency is 1 wave per second. Frequency is measured in hertz (Hz)
Speed Light waves travel faster than sound waves (about a million times faster!) Speed = how far the wave travels in a given length of time Speed = distance/time
Related Formulas Speed, wavelength and frequency are related to one another Speed = Wavelength X frequency Frequency = Speed/Wavelength Wavelength = Speed/Frequency If you increase the frequency, the wavelength decreases
Mini-Lab! Station 1- Frequency Station 2- Amplitude Station 3- Speed Station 4- Wavelength
Practice Complete the practice Wave Math worksheet for homework!
Reflection When a wave hits a surface through which it cannot pass, it bounces back.
Refraction When a wave enters a new medium at an angle, one side of the wave changes speed before the other side causing the wave to bend.
Diffraction When a wave moves around a barrier or through an opening, it bends and spreads out
Constructive Interference Waves combine to make waves with a larger amplitude
Destructive Interference When two waves combine to make a wave with a smaller amplitude.
Waves Lab Needed materials: water, container, dropper, Using pages O 24, follow the lab instructions. Answer the analysis questions. Do not answer question 6. Write & fill in the table.
What are Waves? Waves that do not require a medium to travel are called electromagnetic waves Light from the sun
Electromagnetic Waves Transverse wave that transfers electrical and magnetic energy Moves at the speed of light (186,000 miles per second) Do not require a medium, so they can travel through empty space, like space (vacuum)
Electromagnetic Spectrum All electromagnetic waves travel at the same speed, but they have different wavelengths and frequencies. The electromagnetic spectrum is the complete range of electromagnetic waves in order of increasing frequency
Light Energy, AKA Electromagnetic Light behaves like waves and packets of energy at the same time The amount of energy carried by an EM wave increases with frequency
Electromagnetic Spectrum Made up of: Radio waves-radio, tv, microwaves Infrared rays-heat lamps, infrared cameras Visible light-colors, light we see Ultraviolet rays-rays from the sun X-rays-medicine, engineering Gamma rays-some radioactive materials
Electromagnetic Project Answer questions 1-2 on page O81 Draw and label the Electromagnetic Spectrum. Follow the example I show. Use page O74.
Light Energy Demo Demonstrate how white light can be separated into the visible color spectrum. As light passes through a prism, the waves are bent or refracted Red wavelengths bend the least Complete five different observations with the prisms. For each, draw (using the colored pencils) the way you see the light separated.
Worksheet Complete the worksheet Properties of Waves You may use your notes, not your neighbor! Complete the worksheet Interactions of Waves. Use book pages O 17-23.
Properties of Waves Complete the worksheet Waves & Energy You may use your book or notes as a reference if necessary.
Waves Reading & Worksheet Read pages O 17-26. Use the worksheet provided as a guide to your reading Complete the worksheet Interactions of Waves
Waves Electromagnetic Do need a to travel through. Don t need a to travel through. Transverse Waves Lowest parts called. waves. Spread-out parts called. Examples of EM waves: (pg O 74) Highest parts called. Close-together parts called.
ENERGY! Types of energy: Light Sound Earthquake waves Heat Wind Electrical Chemical Nuclear Energy is the ability to do work or cause change When an object is moved because of energy, the energy is transferred to the object Energy is measured in JOULES (J)
Potential & Kinetic Energy Kinetic Energy: The energy an object has due to its motion What can effect kinetic energy? Velocity has a greater impact on effecting the overall K.E. Mass more mass means more E to make it move K.E. = ½ X Mass X Velocity ^2 Potential Energy: stored energy that results from the position or shape of an object Gravitational, elastic
Potential & Kinetic Energy Mechanical energy is the combination of kinetic and potential energy Let s talk PENDULUM: draw a picture, label potential and kinetic Let s talk bouncing ball Are these examples cyclic
Energy Three mini-labs to complete with observations 1.Compare the transfer of energy through various mediums Sound Light Heat Earthquake waves
Heat Heat is thermal energy moving from a warmer object to a cooler object. The energy depends on the movement of the atoms lots of movement = higher heat Does temperature rise at the same rate for everything? Hot sand & cold water.
Specific Heat Amount of heat needed to increase the temperature but the temperature does not increase at the same rate for everything
Heat Transfer How is heat transferred? Conduction: heat is transferred from one object to another without the movement of matter. Examples? Convection: heat is transferred by the movement of currents within a fluid. Examples? Radiation: transfer of energy by electromagnetic waves Examples?
Heat Transfer Activity Compare the transfer of heat by conduction, convection & radiation. Provide 3 examples of each.
Conversion of Energy Most forms of energy can be transformed into another type of energy Mechanical (movement) to electrical, such as a dam Toaster: Electrical to heat Cell phone: Electrical to electromagnetic Your body: Chemical to mechanical, Chemical to thermal
Response to Energy Plant to sunlight? Humans to light, sound, motion Cockroaches to light intensity
Review Name 3 devices that help people sense types of energy: i.e., seismograph Define conduction, convection, and radiation. Give 2 examples of each. Think of an example of energy transformation between the following: Mechanical to mechanical Electrical to heat Chemical to electrical Electrical to electromagnetic Mechanical to sound Write 3 facts about mechanical waves, transverse waves, longtitudinal waves, and electromagnetic waves
Review Section M Page 201-202: 1, 3, 5-9, 11-15, 19, 23 Section O Page 31: 1-7 Page 32: 9-11, 13, 19 Page 33: 1, 2, 3, 5, 6 Page 101: 1, 2, 3, 7 Page 102: 11, 13, 14, 15 Page 103: 1, 2, 3, 4, 6