Unit F Forces and Energy
Experiments 571,
- Lesson 1 Motion pg. 570
- Position
- Location of an object
- Motion
- Change in position over time
- Distance
- Direction
- Frame of reference
- Group of objects from which you can measure a position or the motion
- Speed
- Fast an objects position changes over time
- Distance traveled divided by time spent traveling
- Mph (miles per hour)
- Velocity
- Measurement that combines both speed direction of moving object
- Acceleration
- Change in velocity over time for an object
- Slowing down or speeding up is a change
- Going forwards backwards or sideways is change in direction
- Momentum
- Product of mass multiplied by velocity
- Change mass or velocity
- Inertia
- Tendency of any object to resist a change in motion
- Or of a moving object to keep moving straight line
- More mass object has more inertia
- Forces and Motion Lesson 2 pg. 582
- Force
- Any push or pull from 1 object to another
- Friction
- Force that opposes the motion of 1 object moving past another
- Smooth surfaces have less friction
- Heat is produced in friction
- Air resistance slows down the object
- Water resistance slows it down
- Balanced Forces
- Forces act on an object w/o changing its motion
- Stays constant speed same direction
- Friction of tires, engine pushing bus forward, wind dragging
- Unbalanced forces
- Force causes an object to change its motion
- Sir Isaac Newton studied forces
- Newton’s 1st Law of Motion
- Object at rest stays at rest
- Object in motion stays in motion
- Unless acted on by an unbalanced force
- Push or pull changes the motion
- Friction or drag
- Law of Inertia
- Newton’s 2nd Law
- The unbalanced force on an object
- Is equal to the mass of the object
- Multiplied by its acceleration
- F = m x a
- Newton’s 3rd Law
- All forces occur in pairs
- These 2 forces are equal in strength
- Opposite in direction
- Action force
- Push of 1st object on the 2nd object
- Reaction force
- Push of 2nd object back on 1st object
- For every action there is an equal but opposite reaction
- You push on a wall while roller skating what happens
- Work and Energy Lesson 3 pg. 596
- Work
- Measurement of energy used to perform a task
- Energy
- Ability to perform work or to change an object
- Potential Energy
- Potential to do work
- Energy stored in the position or structure of object
- Kinetic Energy
- Energy of a moving object
- Positive work adds energy to object
- Law of Conservation of Energy
- Energy can’t be created or destroyed
- It can only change form
- Gains kinetic energy but loses potential energy
- Simple Machines Lesson 4 pg. 606
- Simple Machines
- A machine that takes one force and changes its direction, distance or strength
- Effort
- Force you apply to machine
- output
- Force a machine supplies
- Load
- Object moved by the output
- Work= force x distance
- Lever on teeter totter
- Pulley
- Wedge
- Screw
- Wheel and axle
- Inclined plane like a ramp
- Lever
- Bar that rotates around
- Fulcrum
- a pivot point
- crowbars, seesaws-1st class levers
- wheel barrow 2nd class lever
- fishing pole-3rd class levers
- Compound machine
- 2 or more simple machines are combined
- Tow trucks, elevators
- Efficiency
- Ratio of input energy to output work
- Heat Lesson 1 pg. 624
- Heat
- Thermal energy that flows between objects due to a difference in temperature
- Temperature
- Measurement of the average kinetic energy of particles in an object
- Particles vibrating faster makes temp higher
- Measured w/ a thermometer
- Conduction
- Passing of heat through a material while material stays in place
- Stirring hot cocoa with a metal spoon
- D. Convection
- Flow of thermal energy through a liquid, or gas
- caused by hot parts rising cool parts sinking
- Radiation
- Transfer of energy through electromagnetic rays
- Visible light, x-rays, radio waves
- Infrared Rays
- Close in color to red visible light
- Electromagnetic rays are produced
- Can’t see them
- Radiate heat
- Thermal Conductivity
- Ability of a material to transfer heat
- Conducts heat easily
- Heat capacity
- Materials with low heat capacity changes temp quickly
- Sound Lesson 2 pg. 636
- Compressions
- Regions of air that has many particles
- Rarefactions
- Regions of air that have few particles
- Sound Wave
- Series of rarefactions and compressions traveling through a substance
- Medium
- Substance which the wave travels through
- Carries energy
- Vacuum
- Region that contains few or no particles
- No medium travels through region
- Absorption
- Transfer of energy when a wave disappears into a surface
- Echoes
- Sound waves reflected back
- Frequency
- Number of times an object vibrates per second
- Pitch
- How high or low a sound is
- Related to frequency
- Doppler effect
- Change in frequency due to moving away or toward wave
- More times it vibrates makes pitch higher
- Amplitude
- How dense the air is in the compressions or rarefactions compared to normal air
- Echolocation
- Echoes bounce off an object and back to tell where things are located
- Sonar
- Sound navigation and ranging
- Sends out sounds waves that reflect off of objects
- Return time and direction determine location
- Light Lesson 3 pg. 650
- Wavelength
- The distance between one peak and the next in a wave
- Photon
- Particles of light
- Tiny bundle of energy by which light travels
- Translucent
- Objects that blur light as it passes through it
- Transparent
- Objects allow most light through it
- Opaque
- Allows no light to pass through it
- Image
- Picture of light source that light makes when it bounces off a shiny surface
- Law of Reflection
- The angle of an incoming light ray equals the angle of the reflected light ray
- Refraction
- Bending of waves as they pass from one subStance into another
- Convex mirrors
- Curved out
- Images always appear upright and reduced
- Concave mirrors
- Curved in
- Images upright or upside down, enlarged or reduced
- Prism
- Separates light when passing through an object
- Spectrum
- Band of color in rainbow
- From light passing through a prism
- Electromagnetism
- Way in which electric and magnetic forces interact
- Electricity Lesson 4 pg. 664
- Electricity
- Movement of electrons
- Static Electricity
- Buildup of charges particles
- Two objects rub together
- Electrons are knocked of one object and onto the other object
- Grounding
- Occurs when a conductor shares its excess charge with a much larger conductor
- Electric Current
- Flow of electricity through a conductor
- Circuit
- Formed when an electric current passes through an unbroken path of conductors
- Voltage sources
- Moves electrons along the path
- Increases volts of electrons in circuit
- Batteries
- Switch
- Device that can open or close the path
- Resistor
- Object in electrical circuit resists the flow of electrons
- Measured in ohms
- electrons loses energy
- lightbulb
- amperes
- electric charge measured in units
- Short circuits
- Shorts the circuit and can start a fire or damage appliance
- Breakers
- Switch that opens when it detects too much current
- Fuse
- Wire breaks if too much current flows through it
- Ground fault interrupter
- Sensitive to changes in current
- Usually has a red button on it
- Turns outlet off
- Magnetism Lesson 5 pg. 676
- Magnetism
- Ability of an object to push or pull on another object that has the magnetic property
- North Pole
- South pole
- Magentic field
- Lines that show the area of the magnetic forces around a magnet
- Closer the lines the stronger magnetic force is
- Electromagnet
- Electric circuit that produces a magnetic field
- Voice coil
- Operates audio speakers
- Generator
- Device that creates electric current
- spinning an electric coil between the poles of a magnet
- Alternating Current
- Electric current that rapidly changes directions
- Magnetic Levitation
- Lifting of an object by means of magnetic forces
- Used by trains to travel on tracks