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