a. A wave is a disturbance which moves through a medium b. Amplitude: the height of the wave c. Crest: The top of the wave d. Trough: The bottom of the wave e. Wavelength: the distance from one crest to the next or one trough to the next f. Frequency: number of complete cycles in one second g. Period: the time taken for one complete cycle

a. Waves move energy from one place to another without moving matter. b. Most waves move through matter c. Mechanical waves: require a medium to travel through (air, water, ropes) i. There are three different mechanical waves. 1. Transverse waves: move up and down 2. Longitudinal waves: move side to side 3. Surface waves: these are a mix of transverse and longitudinal

d. Electromagnetic waves: do not require a medium to travel through i. Example: Light and Radio e. The unit of Frequency is Hertz (Hz)

a. These waves can travel in a vacuum b. The energy transferred by these waves are called electromagnetic radiation c. This is how the sun’s energy arrives to earth d. The only waves we can see are Visible Light Waves.

a. This spectrum is made up of radio wave, microwaves, infrared rays, visible light waves, ultraviolet rays, X-rays, gamma rays b. Radio waves: use in broadcasting to carry signals for radio programs. i. Your radio picks up the radio waves and converts them into electrical signals ii. These electrical signals are converted into sound

c. Microwaves: shorter wavelengths and higher frequencies than radio waves i. Used in cellular communications and radar d. Infrared rays: the invisible heat you feel i. Also called Infrared radiation e. Visible light: make up only a small part of the spectrum. i. Visible light that appears white is the mixture of all the different colors. ii. Blackness is the absents of light iii. Visible light bends and refracts when entering a new medium.

f. Ultraviolet rays: High energy, therefore can damage or kill living cells. i. Too much exposure burns your skin and can cause skin cancer g. X-rays: can penetrate most objects i. Bones and Lead absorb X-rays h. Gamma rays: shortest wavelengths and highest frequencies. i. Most dangerous because they have the highest energy. ii. Can look at the bodies internal structures.

a. Transverse vs. Longitudinal i. Transverse waves move perpendicular to the medium. ( S wave) ii. Longitudinal waves move parallel to the medium. ( P waves) 1. Example: Sound Waves

b. Longitudinal Waves i. Vocabulary 1. Compression : when the waves are close together 2. Rarefaction: when waves are far apart. ii. To find the wavelength in a longitudinal wave, measure from one compression to the next.

c. Sound waves i. Pitch is the frequency of sound 1. This is measured in Hertz (Hz) ii. As wavelength increases, pitch decreases 1. Therefore, a low pitch sound has a long wavelength 2. Therefore, a high pitch sound has a short wavelength. 3. Between a low pitch and a high pitch, which wave has the most energy? iii. Humans hear between 20 Hz and 20,000 Hz.

iv. Label one picture “Deep Pitch” and one picture “High Pitch”

v. We measure sound volume with the unit decibels (Db) vi. the loudness of a sound wave depends on the amplitude 1. The higher the amplitude of the wave, the louder the sound. 2. The louder the sound, the higher the decibels.

vii. Labe one Picture with “High Volume” and label one picture with “Low Volume”

a. How to find the period of the wave. (speed) i. Speed = frequency x wavelength ii. V=f( λ ) iii. Frequency = Speed ÷ wavelength iv. f=V/ λ v. Many time wavelength is measured in Nanometers (nm)

1. Example. If I have a sound wave with a frequency of 12 Hz and a wavelength of 3 cm. What is the Speed of this wave? 2. Example: If I have a wave with a speed of 14 cm/s and a wavelength of 2 nm what is the Frequency of this wave?

1. If there is a wave moving at a frequency of 35 Hz and the wave has a wavelength of 3 nm. What is the Speed of this wave? 2. If a sound wave is moving at a speed of 6 nm/s and has a wave length of 8 nm. What is the frequency of this wave? 3. Compare these two sound waves. wave 1: Amplitude of 3 nm and a wavelength of 5 nm wave 2: Amplitude of 7 nm and a wavelength of 2 nm a. Which of these two waves has a higher pitch? b. Which of these two waves has a higher volume? 4. Describe the difference between “Compression” and “Rarefaction”

a. Law of Reflection: the angle at which a ray approaches a surface is the angle at which the ray will be reflected off the surface (draw) b. Two different kinds of Reflection i. Regular reflection and diffuse reflection ii. Regular reflection: occurs when parallel rays of light hit a smooth surface. 1. This creates an image 2. An image is a copy of the object 3. Examples of surfaces: Glass, metal, and still water

iii. Diffuse reflection: occurs when parallel rays of light hit an uneven surface. 1. This still follows the Law of Reflection 2. Most light reflects diffusely 3. There is either no image or the image is unclear. (draw)

c. Mirrors i. Plane mirrors: a flat sheet of glass with a smooth, silver colored coating on one side. 1. Due to the smooth coating, light reflects by regular reflection creating a virtual image. 2. This image is the same size and same direction as the object

ii. Concave Mirrors: a mirror with a surface that curves inward (like the inside of a bowl) 1. Optical Axis: an imaginary line that divides the mirror in half. 2. Focal Point: where the rays reflect and meet off the concave surface 3. These can produce a Real image. These images are upside down. (draw)

iii. Convex Mirrors: a mirror with a surface that curves outward 1. Produces a virtual image that is smaller than the object (draw)

1. What is the Law of Reflection? 2. Explain the difference between a Concave Mirror and a Convex Mirror. 3. Draw a diagram of a Concave mirror being hit by parallel rays of light. (include optical axis, focal point) 4. Does a Convex mirror produce a Virtual Image or a real image? 5. What is the difference between a Virtual image and real image?

a. When light passes through or hits objects it can be refracted, reflected and/or absorbed. i. Refracted light may cause you to see something that is not actually there. ii. The more transparent an object is the less light will be absorbed into that object iii. An opaque object will both reflect and absorb light

b. Refraction i. As light enters a new medium the speed that the waves move changes, depending on the medium. ii. This change in speed is what causes the light to bend iii. The Speed of Light will slow down when it enters water or glass iv. Draw:

v. Index of Refraction 1. This is how much light bends in a given medium. 2. The greater the index the greater the bend 3. Fill in this Chart MediumIndex of Refraction Air1.00 Water1.33 Corn Oil1.47 Diamond2.42

b. Prisms i. When light rays enter a prism each wavelength is refracted in a different way. 1. The longer the wavelength the less it is bent 2. Due to this difference in refraction each wavelength is separated from the other. 3. This in turn creates a rainbow. a. Red: refracts the least (longest wavelength) b. Violet: Refracts the most (shortest wavelength.)

ii. Rain 1. Rain Droplets act as tiny prisms 2. rain droplets refract the light coming into them and they create a rainbow in the droplet 3. Once the light hits the other side of the droplet it is reflected out of the droplet 4. When there are thousands of rain droplets reflecting out it creates one giant rainbow

c. Mirage i. An image of a distance object cause by refraction of light e. Lenses i. A lens is a curved piece of glass or other transparent material ii. Two different kinds of lenses 1. Concave Lenses and Convex Lenses

iii. Concave Lenses 1. These lenses have a thinner center compared to its edges 2. When the parallel light rays pass through the concave lens, the rays bend away from the optical axis. 3. This bend away causes the object to appear smaller than it really is

iv. Convex Lenses 1. These lenses have a thicker center compared to its edges 2. When the parallel light rays pass through the convex lens, the rays are bent toward the optical axis 3. This bend toward the axis causes the objects to appear larger than they really are. 4. Convex lenses are used in glasses and contact lenses.

1. Describe how a rain droplet creates a rainbow? 2. How are convex lens different than convex mirrors? 3. If object number 1 has an index of refraction of 2.3 and object number 2 has an index of refraction of 1.9. Which object bends light more?

Unit 2 Continued

a. Energy is the ability to do work or cause change b. Energy can change form and change state c. A state of matter is a form in which matter exists

a. First Law of Thermodynamics: Energy cannot be created or destroyed b. Second Law of Thermodynamics: Heat can only go from a hotter to a cooler c. Three States of Matter i. Solid, liquid, and gas

i. Solid 1. Has a definite shape and volume 2. Particles are packed together tightly and have ordered arrangement

i. Liquid 1. Has a definite volume but no shape of its own 2. Particles are packed tightly but not as rigidly as a solid. 3. These particles can move freely around each other

i. Gas 1. Has no definite shape or volume 2. The particles will spread apart to fill their container

d. Changing of State i. Freezing point: the point at which a liquid becomes a solid ii. Boiling point: the point at which a liquid becomes a gas 1. Because heat can only go from a hotter to a cooler, as the heat goes into the liquid it causes the particles to vibrate faster

e. Energy and Change of State i. Potential Energy: this results from the position or the shape of an object ii. Kinetic Energy: this results from the motion of an object ii. The total Kinetic and Potential energy in the particles in an object is called Thermal Energy 1. When heat is added to a system the Thermal Energy changes 2. When a system loses or gains Thermal Energy it can cause the substance to change state.

f. Forms of Energy i. Forms of energy has to do with the small particles in the object ii. Nuclear Energy: comes from the nucleus of an atom 1. An atom is the smallest building block of our world 2. This energy is released during a Nuclear Reaction 3. These reactions are created in nuclear power plants to create an alternative power source a. This power is harnessed by a process called Fission (the splitting of atoms)

iii. Thermal Energy: total amount of kinetic and potential energy of the particles in an object. 1. The amount of movement is the kinetic energy of the particles 2. The arrangement of particles is the potential energy iv. Electrical Energy: this is the energy of an electrical charge 1. This is the energy inside batteries and electrical outlets

v. Electromagnetic Energy: formed when energy travels through space in waves 1. These are vibrating electrical charges 2. These do not require a medium, they can travel through a vacuum vi. Chemical Energy: Potential energy stored in chemical bonds 1. Chemical Bonds hold atoms together 2. When the bond is broken energy is released 3. Examples: Food, matches

g. Energy Transformation: a change from one form to another form i. Single Transformations: One energy being transformed into another form to do work. 1. Example: your body, takes chemical energy from food and changes it into mechanical energy.

ii. Multiple Transformations: Series of transformations are needed to do work. 1. Example: A car. Electrical Energy in the engine produces a spark. The spark is thermal energy and releases chemical energy in the fuel. This eventually transforms into mechanical energy that turns the car.

h. Energy Conservation: First Law of Thermodynamics i. Total Energy before transformations is the same as the total energy after the transformation ii. The energy has just changed form iii. Friction: force one surface exerts on another surface 1. Friction transforms kinetic energy into thermal energy.

a. Thermal Energy: total energy of all the particles i. Potential and Kinetic Energy combined ii. Factors: 1. Objects Temperature 2. Number of particles in the object 3. How the particles are arranged iii. The more particles in an object at a given temperature the more thermal energy it has 1. A 1-liter pot of tea compared to 0.2 mug of tea at 75 degrees.

iv. Difference between heat and thermal energy 1. Thermal energy is the temperature you feel 2. Heat is the transfer of thermal energy from a warmer object to a cooler object. a. The warmer object will cool down, the cooler object will warm up until the two objects are the same temperature

a. Three ways heat is transferred i. Conduction: transfers heat from one particle to another 1. Example: Stove tops. Heat goes from the burner to the pot or pan

ii. Convection: only occurs in fluids. Such as water and air. 1. Heated air is less dense than cooler air 2. Hot air rises above the cool air 3. This flow is called the Convection Current 4. This current in air is what causes wind and weather changes

iii. Radiation: transfer of energy by electromagnetic waves 1. Only form of heat that does not require matter 2. Example: Feel the radiation from a fire without touching it