May 1, 2018 Mental Math…be ready. You need: Clean paper (2) / pencil Warm Up: Mental Math…be ready. I CAN: demonstrate unbalanced and balanced forces with magnets. I CAN: show a transfer of energy through electrical circuits.

Today’s agenda Mental Math Reminders/calendar Review simple machines and Newton. Magnets and Circuits

Swagrrr No 7th test ELA 7 Math 7 Math I May 2018 Sunday Monday Tuesday Wednesday Thursday Friday Saturday   Forces and energy Magnets 1 Magnets / eclectricity 2 Electricity 3 Catch up 4 Review Test Assess MobyMax Milkshakes 5 6 7 Atmosphere 8 9 10 11 12 13 Mother’s Day 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 No School Memorial Day 29 30 31 APRIL 30 Progress reports Swagrrr No 7th test ELA 7 Math 7 Math I

June 2018 EOG testing ELA 7 Math 7 Math I Busch Gardens NCFE SS/Sci 7 Sunday Monday Tuesday Wednesday Thursday Friday Saturday   1 Atmosphere 2 3 4 5 6 7 8 Last day (due to snow) 9 EOG testing ELA 7 Math 7 Math I Busch Gardens NCFE SS/Sci 7 NCFE testing

Simple Machines (Making work easier…phew!) REVIEW

Simple Machines Foldable 8 Simple Machine Notes 7 Lever 6 Pulley 5 Wheel & Axle 4 Wedge 3 Screw 2 Inclined Plane 1 Title Tab Simple Machines By John Smith REVIEW Line up your papers about 1-2 cm apart Fold the papers over. Number and title each flap

REVIEW How do machines do work? Machines make work easier by changing 3 things about the FORCE you exert to do work: AMOUNT OF FORCE you exert DISTANCE over which you exert force DIRECTION in which you exert force

What are SIMPLE MACHINES? REVIEW There are only 6 basic simple machines that make work easier: Inclined Plane Wedge Screw Lever Wheel & Axle Pulley

REVIEW COMPOUND MACHINES Compound Machines – are made of combinations of two or more simple machines. For example, a simple can opener is a combination of 3 simple machines: Lever Wheel & axle Wedge

REVIEW WORK & SIMPLE MACHINES Simple machines DON’T change the amount of WORK done! (They change the size, distance or direction of your FORCE!) WORK IN = WORK OUT* (*usually machines lose a bit of work due to FRICTION…)

What is the mechanical advantage of a machine? REVIEW A machine’s mechanical advantage is the number of times a machine increases a force exerted on it. Mechanical = Output Force Advantage Input Force

What is the mechanical advantage of a machine? REVIEW You exert 10 N of force on a can opener. The can opener exerts 30 N of force on the can. What is the mechanical advantage? Mechanical = Output Force = 30 N Advantage Input Force 10 N Mechanical Advantage = 3

What is the efficiency of a machine? REVIEW The EFFICIENCY compares: the work you put IN to the work the machine puts OUT. An IDEAL machine is 100% efficient. INPUT WORK = OUTPUT WORK In the real world, some input work is always lost due to FRICTION between the moving parts of the machine.

What is the efficiency of a machine? REVIEW EFFICIENCY = Output Work x 100% Input Work You mow the lawn with a rusty lawn mower. You do 50,000 J of work on the lawn mower but only 25,000 J go to cutting the lawn. What is the efficiency of the lawn mower?

What is the efficiency of a machine? REVIEW You mow the lawn with a rusty lawn mower. You do 50,000 J of work on the lawn mower but only 25,000 J go to cutting the lawn. What is the efficiency of the lawn mower? EFFICIENCY = Output Work x 100% Input Work Efficiency = 25,000 J x 100% 50,000 J Efficiency = 50%

Try these problems on your own… REVIEW Mechanical = Output Force Advantage Input Force EFFICIENCY = Output Work x 100% Input Work

Making a foldable: Newton’s Laws of Making a foldable: Newton’s Laws of Motion On the inside, include the following info for each law: 1) What does the law say? 2) What’s an example of a situation that shows the law in action. 3) Draw a picture that shows the law in action. NEWTON’S LAWS Newton’s First Law of Motion Newton’s Second Law of Motion Newton’s Third Law of Motion

THE LAW OF Newton’s 1st Law INERTIA

Newton’s 1st Law of Motion Newton’s 1st law of motion states: An object at rest will remain at rest, -and- an object moving at a constant velocity will continue moving at a constant velocity, -UNLESS- it is acted upon by an unbalanced force.

THE LAW OF Newton’s 2nd Law Acceleration

Newton’s 2nd Law of Motion Newton’s 2nd law of motion describes how UNBALANCED FORCES and MASS affect the ACCELERATION of an object.

Newton’s 2nd Law of Motion It states: ACCELERATION depends on the object’s MASS, and the net FORCE acting on the object. We can also write it mathematically: Force = Mass x Acceleration

Try one on your own… Ms. Litwak’s van runs out of gas. How much force does she need to push the 2000kg van at an acceleration of 0.5 m/s2? 0.5 m/s2 F = m x a F = 2000 kg x 0.5 m/s2 F = 1000 N right

Newton’s 2nd Law of Motion Speed, Distance & Time We can also write the formula like this: Acceleration = Force Mass Mass = Force Acceleration Force = Mass x Acceleration m F a

THE LAW OF Newton’s 3rd Law Interaction

Which forces are acting to get this guy up in the air? His feet push DOWN on the ground. But wait… His downward push can’t be causing his upward motion.

Which forces are acting to get this guy up in the air? His feet push DOWN on the ground. The ground pushes UP on the man. There must be a force pushing UP! The force of the ground pushes him UP!

Newton’s 3rd Law of Motion Newton’s 3rd law says that: For every action force, there is an equal and opposite reaction force. ALL forces act in PAIRS! Action Force: Man’s feet push DOWN on the ground. Reaction Force: Ground pushes UP on the man.

Identify the force pairs in each situation A space shuttle lifts off. Action Force – engine pushes gases down & out. Reaction Force – the gases push the rocket up. *This upward force must be stronger than gravity pulling down on the rocket!

Identify the force pairs in each situation A person stands still. Action Force – gravity pulls the person down to the floor. Reaction Force – the floor pushes up on the person. *You don’t need MOTION for force pairs. They are everywhere!

What is Momentum? Momentum is a measure of how much motion object has. It is affected by mass and velocity. The heavier an object is, the more momentum it has. It’s easier to stop soccer ball coming towards you at 20 m/s than a car coming at 20 m/s. It’s easier to stop car travelling at 1 km/h than a car travelling 60 km/h!

Conservation of Momentum When objects collide, their total momentum is conserved (stays the same), unless outside forces act. The total amount of motion coming into a collision will also come out of the collision.

Place 4 coins in a row, touching each other. Place the 5th coin about 2 inches away from the end of the row, keeping it in line. Lightly flick your finger forward, propelling the single coin against the others. What do you observe? Try it again, flicking 2 coins into a row of 3 coins. What do you observe?

Momentum = mass x velocity Momentum can be calculated using this formula: Momentum = mass x velocity A golf ball with a mass of 0.05 kg travels at 16 m/s. A baseball with a mass of 0.15 kg travels at 7 m/s. Which ball has the greater momentum? Golf ball’s momentum = 0.05 kg x 16 m/s Baseball’s momentum = 0.15 kg x 7 m/s = 0.8 kg m/s = 1.05 kg m/s

Magnets What do you already know? List at least three things

Magnets Work with your elbow partner (so you can use the ONE desk – not across the desks). Use the marble and magnet. What can you do? Why? WRITE IT DOWN! Using the terms balanced and unbalanced forces, write three sentences about your magnet investigation.

Magnets Magnets create unbalanced forces. Magnets can use that unbalanced force to create motion…for certain metals. Magnets can therefore cause acceleration (change in speed or direction). Magnets are related to Earth. Magnets are related to positive and negative charges – like electricity.

Circuits

Let’s act it out! Make a circle = CIRCUIT What can you figure out? Follow this with an energy ball (or start with the energy ball?)

Electricity It is the flow of the ELECTRONS that we call electricity. An electron is one of the tiny particles within an atom. An atom is the smallest thing that is still recognized as a basic element (not just a part or piece of something larger).

Electricity It is the flow of the ELECTRONS that we call electricity. This flow of electrons is how the current is approximately measured. Can you count how many electrons flow past a given point in one second? One COULOMB is about: 6 x 1018 6, 000,000,000,000,000,000 6 quintillion One AMPERE (Amp) is really one coulomb of electrons going past a point each second.

Key Vocabulary Electricity: A source of power generated from the flow of electrical current. Electron: A small, atomic particle with a negative charge. Energy: The ability to do work.

Key Vocabulary Circuit : A path through which electrical current can flow. Circuit Diagram : An illustrative picture used to explain the paths through which electricity can flow. Conductor: A material that allows for electrical current to flow. Current: The flow of electrons through a conductor.

Circuit Just examples – two “easy” or “simple” and two that are…not.

Electrical shorthand We have created a “short-hand” or a way to draw out circuits using symbols. Bulb/lamp/light – can be used as an indicator to simply show there is electrical flow OR may be the main purpose for the circuit Bulb

Electrical shorthand Wire/wiring – the connection between parts, allows for flow (and extension over distances), must be a CONDUCTOR, typically is covered with INSULATION to protect those who may come in contact.

Negative Positive Electrical shorthand Battery Power source - in simple circuits that power source is most likely a battery. Battery Negative Positive

Electrical shorthand Switch - closed (allows flow) Switch - open (stops flow)

Electrical shorthand Motor Buzzer Sometimes you may want to add in a motor or a buzzer (sound maker)… Motor Buzzer

Let build! – Simple Circuit 1st DRAW out a simple circuit with one bulb and one battery. 2nd BUILD your simple circuit = try to make your bulb light up. 3rd DRAW / WRITE = what worked and why, what did not work and why. BONUS: Can you create / add in a switch?

Clean up! Your “creation” should be drawn on your paper – so you aren’t losing the info/design. All supplies OFF of the “circuit board” Wires / bulbs should be separated (not wound together) Wires / bulbs go back into the cup Tape should be put around the outside of the cup

What if I have a need for more lights? I want to have three lights over my dinner table. Can you create a circuit to help? EXTENSION: this is great for those who can move ahead while waiting for others to finish.

Let build! Series Circuit 1st DRAW out a series circuit with multiple bulbs and ONE battery. 2nd BUILD your series circuit = try to make your bulbs light up. 3rd DRAW / WRITE = what worked and why, what did not work and why.

But… If ONE bulb burns out, I don’t want to lose all three. How do I fix that?

Let build! Parallel circuit 1st DRAW out a parallel circuit with multiple bulbs and ONE battery. 2nd BUILD your parallel circuit = try to make your bulbs light up. 3rd DRAW / WRITE = what worked and why, what did not work and why.

Clean up! Your “creation” should be drawn on your paper – so you aren’t losing the info/design. All supplies OFF of the “circuit board” Wires / bulbs should be separated (not wound together) Wires / bulbs go back into the cup Tape should be put around the outside of the cup

Let discuss Share what you built What would happen if the battery were turned around in the circuit? Which would be brighter…light bulbs in series or light bulbs in parallel? Why? Briefly describe the differences between a parallel and a series circuit.