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Acutus Mens
Science Reviews
Question | Answer |
---|---|
Define wave. | A periodic disturbance in a solid, liquid, or gas as energy is transmitted through a medium. |
Give 3 examples of media. | Solid, Liquid, Gas |
What 2 things can waves travel through? | Matter and Space |
What does a wave carry? | Energy |
What kind of waves require a medium? | Mechanical Waves |
What kind of waves do NOT require a medium? | Electromagnetic Waves |
What do we call waves that are produced by a combination of longitudinal and transverse waves? | Surface Waves |
What is amplitude? Why is it significant? | Height of the wave from the rest point; Larger amplitude = more energy |
What is frequency? Why is it significant? | The number of waves produced in a given amount of time; as frequency increases, wavelength decreases and vice versa |
How do we calculate wave speed? | Wave speed (γ) = wavelength (λ) X frequency (f) |
What is the relationship between frequency and wavelength? | As frequency increases, wavelength decreases and vice versa |
Differentiate between reflection, refraction, and diffraction. | Reflection – the bouncing back of a wave; Refraction – the bending of a wave as it changes medium; Diffraction – bending of a wave around a corner or through a hole |
What is interference? Explain the two types of interference. | When waves overlap. Constructive – waves overlap and builds (gets louder or brighter); Destructive – waves overlap and collapse (dimmer light or creates noise) |
What is a standing wave? Give an example. | Pattern of vibration that stimulates a wave that is standing still (looks like it is standing still); car wheels spinning while driving |
Explain resonance. Give an example. | When 2 objects naturally vibrate at the same frequency; sound produced by one causes the other to vibrate; loud radio bass causes mirrors to vibrate |
What kind of wave is a sound wave? | Mechanical and Longitudinal |
How does sound travel? | By vibration |
In what direction do sound waves travel? | All directions. |
Define a medium. | An object through which a wave travels (solid, liquid, gas). |
What are the 3 sections of the ear? | Outer, Middle, Inner |
What are the 3 bones in the middle ear called? | Hammer, Anvil, Stirrup |
What is responsible for transmitting sound electrically to the brain? | Cochlea |
Predict what may have happened if a person has lost their hearing | (answers will vary). |
What are the 3 kinds of instruments? | Strings, Winds, Percussion |
What is pitch? How is it related to frequency? | How low or high a sound seems to be; high pitch = high frequency and low pitch = low frequency |
What do we call sounds that have a frequency too high to hear? | ultrasonic |
What happens when a jet breaks the sound barrier? | Build up of constructive interference; as the jet reaches the sound barrier, the constructive waves move quickly to the back of the jet resulting in rapidly moving particles that create a sound know as a “sonic boom” |
Describe the Doppler effect . | Change in frequency of a wave when the source or observer is in motion (like severe weather warning sirens). |
Define noise. | Random mix of frequencies (depends on listener). |
Define loudness. What is the unit used to measure loudness? | How well a sound can be heard; decibel |
How are amplitude and frequency related? | High amplitude = high frequency and vice versa |
What is used to change a longitudinal sound wave into a transverse wave? | Oscilloscope |
What is an echo? | Reflected sound wave |
What surface reflects an echo the best? | Flat, smooth surface |
What is an electronic echo called? | Radar |
What do we call the process of using sound to locate an object? | echolocation |
What medical procedure allows us to “see” inside the body without surgery? | Ultrasonography (ultrasound) |
Define a sonic boom. | The crashing of constructive waves built up as a jet passes through the sound barrier. The particles crash together all at once resulting the very loud sound. |
What are the 2 kinds of standing waves? | Fundamental and resonant frequencies |
Define sound quality. | Blending of pitches through interference. |
Define noise. | Random mix of frequencies (depends on listener). |
What is an electromagnetic wave? | A wave that is made of electric and magnetic fields that vibrate – does not require a medium. |
Define radiation. | Transfer of energy by electromagnetic waves. |
What is the electromagnetic spectrum? | All the frequencies or wavelengths of electromagnetic radiation; divided based on wavelength |
List the waves of the electromagnetic spectrum in order from longest to shortest. | Radio Waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-Rays, Gamma Rays |
Differentiate between the 2 kinds of reflection. | Regular – reflection seen when using a flat, plane mirror; Diffuse – reflection seen when using a contoured mirror (like a fun house mirror). |
Compare absorption to scattering. | Absorption – light particles are absorbed by the object (very little light is reflected); Scattering – light is largely reflected (like a disco ball) |
What is refraction? Give an example. | Bending of a wave as it changes medium; a light beam travelling through a piece of paper (gas to solid, then back to gas) |
Define diffraction. | Bending of light around corners or through a hole (under a door, etc.) |
What are the three things light can do? | Reflect, Absorb, and Transmit |
What are the 3 kinds of objects and how do they relate to light? | Opaque – absorbs part of light and reflects the rest; Transparent – transmits light; Translucent – absorbs part and scatters the rest. |
When we look at an object, what color do we see? | The color of light that is reflected. |
What happens to the other colors that are not reflected by an object? | They are absorbed. |
What are the three primary colors of light? | Red, Blue, and Green |
When the 3 primary colors of light are combined in equal amounts, what do they create? | White light |
What is pigment? | An opaque substance that reflects and absorbs light. |
What are the three primary pigment colors? | Cyan, Magenta, Yellow |
When the three primary pigments are added together in equal amounts, what is the result? | Black |
Compare the primary colors of light to the primary colors of pigments. | Light – Red, Green, and Blue – combine to make white light; Pigments – Cyan, Magenta, and Yellow – combine to make black |
Draw a convex and concave lens/mirror. | Concave - like a cave, Convex - sticks out |
What is a plane mirror? | Flat mirror |
Which type of lens magnifies? | convex |
Which type of lens make images appear fine and crisp? | concave |
What are the 2 most common vision problems? | Nearsightedness and farsightedness |
What is the function of the following parts of the eye: retina, pupil, lens, optic nerve, cornea, iris? | Retina – contains rods (black,white) and cones (color) Pupil – where light passes through Lens – refracting convex lens Optic Nerve – flips image right side up and sends signals to brain Cornea – provides shape to the eye Iris – colored portion of the eye |
Name 3 ways light affects your life (answers will vary). | Cameras, Telescopes, Lasers, etc. |
What are the properties of a magnet? | Material that attracts ferromagnetic material. |
What are the opposite ends of a magnet called? | poles |
What is magnetic force? | The push or pull exerted by a magnet. |
Explain how a magnetic field works. | The area around a magnet where t he magnetic force is effective. |
How can a magnet lose its’ magnetic alignment? (How can you destroy a magnetic field?) | Striking it very hard, dropping from a very high altitude, heating it. |
How can you create a magnet? | Rub a ferromagnetic material on a strong magnet – only temporary. |
How is the Earth like a magnet? | Has a magnetic field, made of spinning electrons |
Explain the relationship between north and south poles on a magnet. | Like poles repel, opposite poles attract. |
How does a compass work? | Magnetized needle that aligns itself with the magnetic pull of the Earth (pointing North). |
What happens when you break a magnet? | You get 2 new (less powerful) magnets. |
Give an example of a magnetic light show. | Aurora Borealis (Northern Lights) |
What is generated when charges flow through a wire? | Electric current |
What is the unit used to express the amount of charge that flows through a wire? | Amperes (amps) |
What does an electric current produce? What happens if the current reverses? | A magnetic field; the magnetic field reverses as well. |
What can electrical current flow through? | A circuit. |
Define an electric circuit. | The closed path through which charges can flow. |
What are the 3 components to a circuit? | Energy source, wires, load. |
Compare a conductor to an insulator and give an example of each. | Conductor moves current easily – the electrons are loosely bound. Copper is an excellent example. Insulator prevents current from moving – the electrons are tightly bound. Rubber is an excellent example. |
What happens when you flip a switch? | The circuit closes and the electrons are free to move. |
What is resistance? | The opposition to the flow of a charge. |
What object is used to help control resistance? | A resistor. |
Give an example of how resistance is very useful in our lives. | Prevents electrical fires. Your toaster would blow up without resistance! |
Compare a series and a parallel circuit. Use drawings if necessary. | Series connects loads in only one path. Parallel connects to loads on both sides providing multiple paths for current to flow. |
What are the characteristics of a superconductor? | No electrical resistance, very efficient, strongly repels magnets, must be kept very cool. |
How does an electric motor function? | Changes electrical energy into mechanical energy. |
What is a galvanometer? | A device, run by an electromagnet that detects current. |
What is an armature? | A coil or loop in a motor that provides movement for a charge. |
What is the function of a commutator? | Reverses the direction of a charge. |
How does an electric generator work? | Changes mechanical energy to electrical energy. |
What function does a transformer serve? | Speed up or slows down current as it flows through wires. |
What is ferromagnetic material and how is it used in electromagnets? | Material made from iron or nickel that is highly attracted to magnets. It provides the core to an electromagnet. |
How does an electromagnet function? | Has 2 poles that act like switches; when attached to an energy source the ferromagnetic material becomes magnetized. |
What is the coil called that is used in an electromagnet? | A solenoid. |
How can you increase or decrease the power/strength of an electromagnet? | Increase or Decrease the number of coils in the solenoid or add a stronger/weaker ferromagnetic material. |
Give an example of an electromagnet. | A crane in a junkyard, but all of your technological devices contain electromagnets. |
What does the law of electric charges state? | Like charges repel, opposites attract. |
How are an electric force and an electric field related? | An electric force creates an electric field. |
Describe 3 ways to charge an object. Give examples. | Friction–rubbing balloon sticking it to the wall (wiping electrons); Conduction–wiping feet and then touching a metal doorknob (charge transfers by direct contact); Induction–an object is exposed to another charge (Van Degraff Generator) |
What kind of device can detect a charge? | Electroscope |
Explain static electricity and electric discharge. | Charge at rest on an object; touching a conducting object (doorknob) transfers the charge (discharge). |
In relation to electricity, what does it mean to be grounded? | Electric current to transferred to the ground via wires. |
Compare AC to DC. | AC – Alternating Current – moves in 2 directions; DC - Direct Current – moves in |
What is voltage and how it related to energy? | Voltage is the amount of energy needed to push a charge through a wire |
What unit is used to express voltage? | volts |
Why do batteries vary in voltage? | They vary in need and size. |
How does resistance factor in with insulators and conductors? | Conductors have low resistance; Insulators have low resistance. |
If you wanted maximum voltage what kind of wire would you want? Does temperature play a part? | Thick, short wires in a cool setting is ideal! |
What does Ohm’s Law state? | The ratio of voltage to current is constant and referred to as Resistance. |
What unit to we use to measure resistance? | An Ohm - Ω |
Define electric power. What unit is used to express electric power? | The rate at which electrical energy is changed into other forms of energy. (Plug in a lamp and it changes into light and thermal energy). |
One kilowatt (kW) equals how many watts? | 1,000 |
Give examples of series and parallel circuits. | Series – old Christmas tree lights and burglar alarms; Parallel – circuitry in a home or building |
What is a fuse? | Small, thin piece of metal that expands and opens a circuit to prevent the flow of charge. |
How are circuit breakers used in our homes? | To prevent electrical fires; a safety net. |