heat, force, motion, electricity, magnetism, sound, light today is the last day of notes!...as long...
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HEAT, FORCE, MOTION, ELECTRICITY, MAGNETISM, SOUND, LIGHT
Today is the LAST day of Notes!...As long as you behave tomorrow & Friday!!
Heat & Phase Changes
What happens to the speed of the particles in gases as they are exposed to freezing temperatures?
They slow down
What happens if a liquid is vaporized?
It turns into a gas
Phase Change Graph
Heat
Phase Change Graph
Heat
Phase Change Graph
Heat
Phase Change Graph
Heat
Phase Change Graph
Heat
Phase Change Graph
Heat
Phase Change Graph
Conduction, Convection, Radiation
This website I’m going to show you is linked on my website…www.schoolrack.com/abrowder
Thermal Expansion
Alcohol & mercury are liquids that are used in thermometers…why?
Both expand at predictable rates when heated
What do you feel as you drive across the James River Bridge? Why?
Expansion joints are put on bridges because the concrete expands & contracts when what happens?
The temperature changes
Speed
At what speed would a bus have to move in order to travel 40 kilometers in two hours?
20 kilometers/hour
What is the formula for speed?Speed = Distance ÷ Time
Speed = 40 km ÷ 2 hr
Work
What is the definition of work?
•The scientific definition of work = using a force to move an object a distance▫…when both the force and the motion
of the object are in the same direction
Work requires motion…If there’s no motion, there is no work being done
Which of the following is work?
A lamp hanging from a ceiling A man pushing against a concrete
wall A car being towed down a street A rocket drifting through space
Which of the following is work?
A lamp hanging from a ceiling A man pushing against a concrete wall A car being towed down a street A rocket drifting through space
Mechanical Advantage
A large cart on wheels full of bird seed mix that needs to be moved onto a moving truck could be moved either by lifting it above the ground and setting it onto the truck platform or by using an inclined plane. The advantage of using the inclined plane is that the work can be done –
A. more quickly B. with less friction C. using less force D. using less energy
Mechanical Advantage
A large cart on wheels full of bird seed mix that needs to be moved onto a moving truck could be moved either by lifting it above the ground and setting it onto the truck platform or by using an inclined plane. The advantage of using the inclined plane is that the work can be done –
A. more quickly B. with less friction C. using less force D. using less energy
Mechanical Advantage
A truck manufacturer reduces the mass of a car by 350 kg. If the new design is otherwise identical to the old design, how will the new truck compare to the old truck? A. It will have a greater gravitational
attraction to the road. B. It will require more fuel to operate C. It will need less force to move D. It will release more gas emissions
Mechanical Advantage
A truck manufacturer reduces the mass of a car by 350 kg. If the new design is otherwise identical to the old design, how will the new truck compare to the old car? A. It will have a greater gravitational
attraction to the road. B. It will require more fuel to operate C. It will need less force to move D. It will release more gas emissions
Power P = w/t
To finish a project 500,000 Joules of work are needed. The time taken to complete the project is 50 seconds. How much power is needed?
10,000 J/sec
Power = 500,000J ÷50 sec
Simple Machines
A wheel & axle is a lever that rotates around a fixed point. All of the following machines employ a wheel & axle except a –
A. Bicycle B. Skateboard C. Pencil sharpener D. Crowbar
Simple Machines
A wheel & axle is a lever that rotates around a fixed point. All of the following machines employ a wheel & axle except a –
A. Bicycle B. Skateboard C. Pencil sharpener D. Crowbar What type of simple machine is a
crowbar? Lever!
Static Electricity
What are some examples of static electricity?
A balloon sticks to a wall after it is rubbed with a piece of wool.
Laundry in a clothes dryer sticks together because it becomes charged with static electricity. The electrons are transferred as clothes rub against each other in the dryer
When I comb my hair, the hair appears to be attracted to my comb. My hair and the comb must have what type of charges?
Unlike charges
Current Electricity
Direct Current vs. Alternating Current Direct Current = (DC) electric current
that flows through a wire in only one direction Example = current that flows through batteries
Alternating Current = (AC) electric current that reverses its direction regularly Example = used to run appliances
Kinds of Electricity
Static• An electric
charge that collects or builds up on the surface of an object
•Examples– Shocking– Lightening
Current• The flow of
electric charges carried through a material such as wire or other conductors
• Examples– Power lines– Computers– Appliances
What Is Static
Electricity?• A stationary electrical charge that is built up on the surface of a material
Conductors and Insulators
Conductors• Any material that
allows electric charges to move through it
• Examples:– Metals (esp.
copper)– Your body– Electric wires
Insulators• Materials that do
not allow electric charges to flow freely through them
• Examples:– Wood– Glass– Rubber
Simple Circuits
• Series circuit– All in a row– 1 path for electricity– 1 light goes out and the
circuit is broken and all the lights go out.
– Shares voltage; current stays the same across circuit.
– Ex: Old Christmas Lights
• Parallel circuit– Many paths for
electricity– 1 light goes out and the
others stay on– Shares current; voltage
stays the same across circuit.
– Ex: Your house, power lines
Series Circuits
Single Path for Current to Flow
Parallel Circuits
Often missed question…, but you’re gonna ace it next week!
Correct answer = F
1
Magnetism
Magnetism is the attraction of a magnet for another object.
A magnetic pole is the area of a magnet where the magnetic effect is strongest.
Electromagnets Electromagnets are
strong temporary magnets.
Magnetism can be turned on and off
Made by wrapping a wire around a piece of iron and sending a current through the wire.
Magnetic field is in the same direction as the electric current.
Strength of Electromagnets
There are several ways to increase the strength of an electromagnet: Increasing the
voltage or current Increasing the
number of loops of wire
Make the loops of wire tighter
Increase the number of nails in the core
Use iron for the core
Waves
Identify each of the labeled parts of the wave above.
wavelength
trough
amplitude
crest
Identify Compression, Rarefaction, & Wavelength
A = Nothing
B = Wavelength – the distance between one point on a compression and the corresponding point on the next compression in a sound wave
C = Compression – the part that’s squished together D = Rarefaction – the part that’s spread out
What is Sonar?
Uses sound waves to measure the distance between objects underwater• Sonar
– Sonar is a system of detecting reflected sound waves.
– The sonar device measures the time it takes to detect the reflected sound waves.
Which travels faster, sound or light?
Light travels faster than sound.You see the fireworks before you
hear themYou see the lightning before you
hear the thunder
Light
The reason we see things with our eyes is because light is reflected
Reflection of Light
Angle of incidence = Angle of reflection
What property of light causes this pencil to appear bent?
Refraction – because light travels slower through water than through air
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