Vocabulary Terms - Energy energy the ability to do work or cause change (work is force exerted on an object causing it to move a distance) heat Heat is a form of energy that flows between two substances of matter due to their differences in temperature. Hotter to cooler object. Measured in joules. specific heat The amount of energy required to raise the temperature of 1 kg of a substance by 1 Kelvin. temperature A measure of the average kinetic energy of the individual particles in an object heat energy The internal motion of the atoms. The moving particles produce heat. Heat can also be produced by friction (ex. rubbing hands together) chemical energy The potential energy stored in chemical bonds. ex: When fossil fuels are burned, chemical energy is released. A match stores chemical energy. Food and fuel store chemical energy. electromagnetic energy the energy of light and other forms of radiation ex: X-Rays nuclear energy energy stored in the nucleus of an atom electrical energy the energy of electric charges mechanical energy/heat energy associated with the motion and position of an object. To find an object's mechanical energy, and its potential and kinetic energies. ex: you kick a football
fossil fuel All energy in oil, gas & coal originally came from the sun captured through photosynthesis. Fossil fuels release energy that ancient plants captured from the sun. kinetic energy energy of motion potential energy stored energy energy conversion/ change from one form of energy to another form transformation combustion the process of burning fuel Law of Conservation of Energy when one form of energy is converted into another, no energy is destroyed in the process. currents (air, electrical, water) Vocabulary Terms - Heat Transfer heat transfer Heat energy moving from a warmer object to a cooler object by collision of atoms within a substance. conduction The transfer of heat through a material (medium) by direct contact of molecules; without the movement of matter itself. As the molecules are heated, they move faster and bump into one another; creating more heat. Example: A spoon in a cup of hot cocoa. The spoon gets hot. convection The transfer of heat in a fluid (gas or liquid) by means of up & down movement called convection currents. Cooler more dense fluids sink and warm less dense fluids rise.
Example: water boiling or soup in a pot, baseboard heaters heating the room radiation Heat that is transferred through empty space (a vacuum) by invisible infrared rays (electromagnetic rays). No medium is required. Travels at the speed of light in straight lines. This is also known as thermal radiation. For example: Sun warming Earth or a fire warming your body thermal equilibrium A higher temperature object which is in contact with a lower temperature object; will transfer heat until both have a constant (equal) temperature. conductor A substance, body, or device that readily conducts heat, electricity, sound, etc. Example: metal, silver insulator A material or an object that does not easily allow heat, electricity, light, or sound to pass through it. Example: Air, cloth and rubber are good electrical insulators; feathers and wool make good thermal insulators. vibrations Vibrations cause waves. molecules Tiny particles that make up matter. Vocabulary Terms - Waves waves A traveling disturbance that carries energy from one place to another. Parts of transverse waves: crest, trough, Crest - Highest point (peaks) Trough - Lowest point
wavelength, amplitude Amplitude - The greatest movement from rest. Found by measuring the distance from rest to rest or from trough to trough. The greater the amplitude, the greater the energy Wavelength - The distance between 2 consecutive (one after another) crests or troughs. (The shorter the wavelength, the higher the frequency.) Parts of longitudinal waves: compression, rarefaction, amplitude frequency The number of waves passing a point in a certain amount of time. Measured in hertz (Hz). 1Hz=1 wave/sec. (The higher the frequency the greater the energy.) amplitude The greatest movement from rest. Found by measuring the distance from rest to rest or from trough to trough. The greater the amplitude, the greater the energy Mechanical Waves (longitudinal/ compressional, transverse, surface) Waves that travel through a medium. 1. Transverse- vibrates up and down or right to left. The motion of the medium is at right angles to the direction of the wave. 2. Longitudinal (Compressional )- move in and out as a series of compressions and rarefactions. The motion of the medium is parallel to the direction of the wave. 3. Surface Waves- move in circular motion. They are combination waves that move both ways (Transverse and longitudinal) Electromagnetic Waves Light waves that do not require a medium to travel through. They travel through a vacuum (a space free of particles)
ex. Light from sun travels to earth through a vacuum of space. medium The matter (solid, liquid or gas) through which a mechanical wave travels through. Ex. Water is a medium for ocean waves, air for sound waves vacuum Empty Space - the absence of matter light waves Light waves are transverse waves which are the only electromagnetic waves that are visible to the human eye. (Visible Light) sound waves Sound is the disturbance that travels through a medium as a longitudinal wave. Electromagnetic Spectrum The electromagnetic spectrum is made up of transverse waves from gamma rays to radio waves. It is organized from the smallest wavelength (gamma rays) to the largest wavelength (radio waves). reflection when a wave strikes a barrier and bounces back refraction the bending of waves due to a change in speed diffraction the bending of waves around a barrier or through an opening in a barrier interference when two or more waves arrive at the same time and combine into one absorption waves get absorbed into the material; amplitude gets smaller and smaller opaque Opaque materials reflect or absorb all light * Light cannot be seen through this. Example: red plastic cup
transparent Transparent materials transmit all the light passes through, allowing you to see clearly what is on the other side. Example: window translucent Translucent materials scatter the light that passes through them, thus only allowing you to see blurry images. Example: fogged glass Parts of the eye pupil, lens, retina, cornea, iris, optic nerve convex lens A lens that curves outward. Images are virtual (An upright image) or real (images appear upside down) depending on distance from the lens due to parallel light waves that never meet. concave lens A lens that curves inward. Images can only be virtual (Upright) and appear to be smaller. Parts of the ear 1. Outer ear: acts as a funnel to gather sound energy 2. Middle ear: (hammer, anvil, stirrup and eardrum) transfers sound energy from the air to the fluid filled cochlea (found in the inner ear) via the eardrum; which vibrates and amplifies the sound 3. Inner ear: hairlike structure of the cochlea changes vibrations to signals which are passed to the brain pitch (also known as intensity) How high or low the sound is perceived to be. The pitch of a sound wave depends on the frequency of the sound wave. infrasound Sound waves with frequencies below the human range of hearing. ultrasound Sound waves with frequencies above the human range of hearing. echo A reflected sound wave loudness A person s perception of a sound. Loudness depends on the amount of energy it takes to make the sound and the distance from the source of the sound.
sonar a system for detecting waves Doppler Effect the apparent change in frequency of a wave due to the motion of the source. Example: changing pitch of a police car siren as it moves by you. When a sound source moves, the frequency of the waves changes because the motion of the source adds to the motion of the waves.