The Top Ten...

Reasons Newton was a pretty cool dude.


Well this guy Newton taught us a lot of stuff, the most famous being his 3 laws. These laws, however, are the basic ideas behind some pretty fabulous inventions and concepts.






10. We can use Newton's nifty laws to determine the height of a building.

Yep, that's right.Newton’s second law states that force is directly proportional to acceleration and mass is inversely proportional to acceleration.

or...

 a=f/m

From Newton's Second Law we found our way to Free Fall. 

An object in free fall has a constant acceleration of 9.8 m/s^2 (or 10 as we used it). In our lab from Unit 2 we used this nifty number to calculate the height of third Anderson by dropping a ball multiple times from the third floor and taking the average time it took to reach the ground. We then used that average time and using the equation d=1/2gt^2 solved for the distance of the building. 

9. Newton saves our lives with airbags (in terms of momentum)! 

Newtons 3rd law states that for every action there is an equal but opposite reaction. This led into momentum.

Momentum=(mass)(velocity). 
Momentum=p. 
change in p= pfinal-pinitial. 
Impulse=J. J=F(change in t).
J=change in P. 

Momentum will be the same no matter what, so the impulse will be the same. Airbags increase the time impulse occurs, which means the force will be less (remember the big F and little t?). And a smaller force will lead to less of an injury!

8. Newton helps us flip!

Yep, that's right, all those gymnasts you see at the Olympics, they have one big guy to thank: NEWTON.

Newton's first law of motion talks a bit about inertia. It says: An object at rest remains at rest unless acted upon by a force. An object in motion remains in motion, and at a constant velocity, unless acted upon by a force.

Inertia is the tendency of an object to resist any change in its motion.

In Unit 5 Inertia took a different turn.  Rotational Inertia. w\Which is how much an object is willing to spin.

When gymnasts are flipping they tuck their arms close to their body, bringing their mass closer to center, decreasing their rotational inertia and making them spin fast enough to complete the turns.

7. Newton helps us play sports!

Rotational Inertia (which ties back into Newton's first law) can also help us run!

 Runners bend their knees when running because it lowers their center of gravity closer to the base of support making them harder to push down, and in a sports like Lacrosse or Football some contact is possible. Also, by bringing mass closer to the center of mass rotational inertia decreases meaning the ability to spin increases for when they need to be able to make those quick turns

6. Newton helped me make a mouse trap car!

Newton’s 1st Law- this is the law of inertia which states that an object at rest will remain at rest until a force acts to move it and an object in motion will stay in motion until a force acts to stop it. Our car wanted to stay moving so all we had to do to keep it that way was decrease the forces acting to stop it, such as friction.  

Newton’s 2nd Law- this is the law of acceleration which states that acceleration is equal to fnet over mass or a= fnet/m. By making our car lighter we could increase its acceleration because mass is inversely proportional to acceleration. Much the same way if we could increase the force we could also increase the acceleration.

 Newton’s 3rd Law- this is the law of action and reaction which states that for every action there as an equal but opposite reaction. By rotating our axle backwards and winding the string tighter we knew the car would rotate faster forwards.

5. Newton helps us measure force!

This guy Newton was so fabulous, he has his own system of measurement.

Force is measured in Newton's. 

But wait, just what is force you may ask? A force is a push or a pull that acts on an object.

Net Force: all forces acting on an object added together

Equilibrium: when an object is at rest or moving at a constant velocity, when all forces acting upon an object are equal and opposite.

4. Newton explains seat belts!

C'mon, we've all been there, asking why exactly we need those stretchy strips of material keeping us in our seats. 

Well, Newtons first law of motion states that an object in motion will remain in motion and an  object at rest will remain at rest until a force acts upon it. Therefore when a car stops and our bodies are moving forward they want to continue that way a seat belt keeps us from crashing through the windshield. 

3. Newton helps us pack!

Packing can be a hassle, especially when you have all those heavy boxes. Newton's second law helps us figure out how to move those gigantic bins of shoes and blazers.

For example:

If you were pushing an object with 200N of force and the acceleration was 2m/s^2, what would happen to the acceleration is your force increased to 300N? How do you know?

The acceleration would increase because force and acceleration are proportional as defined by Newton’s second law of motion which states that mass is inversely proportional to acceleration and force is proportional.

2. Newton keeps our muscles working!

Newton's third law states that for every action there is an equal and opposite reaction. 

So when we push on a wall or lift weights our muscles feel a force because the weights and the wall are exerting a force on them. The heavier the weight, the more force your muscles have to exert to make the forces equal and opposite.

1. Newton helps us make HOVERCRAFTS!!!!!!!!!!!!!!!!!!

You heard that right. HOVERCRAFT

 Newton's first law states that an object at rest will remain at rest unless acted on by an external force An object in motion continues in motion with the same speed and in the same direction unless acted upon by an external force.

Friction is tension between two objects that are touching. A hovercraft in motion will eventually come to rest because of friction and Newton 's First Law. 

Without Newton, we wouldn't have his first law, then we wouldn't have friction, and then we'd never stop moving!

So thanks Newton, for just being a generally cool dude!

El Fin

The first thing we hopped into with this unit (Unit 7) was magnets and magnetism.

Magnetism is pretty simple, the source of all magnetism is moving charges.

but it can still seem a bit abstract, let's use an example like... a paperclip!

But not just any paperclip, we want to make this paperclip magnetized. To do this we must first recognize clusters of atoms, known as DOMAINS. In your everyday paperclip the domains are unaligned, turning in different directions.

However, if you bring in another player, A MAGNET for example, these domains can be tamed. The magnet has a magnetic field. If we bring the paperclip close to the magnet the domains of the paperclip will align with the magnetic field of the magnet. The paper clip then has a north and south pole. The north pole of the paperclip will stick to the south pole of the magnet. Thus, they attract one another, and the paperclip itself is a magnet.

Wait, wait, wait, hold the phone. Like poles repel and opposite poles attract? How is that possible?

Magnets have both a north and a south pole. The magnetic field in a magnet runs down to the north pole, up, around, and down through the south pole. If you have a south pole of one magnet and the south pole of another magnet, they will repel each other. Like poles repel  because they are both pulling in. 

Then we rode our electron train all the way to Electromagnetic Induction.

Electromagnetic induction occurs when a magnet is moved through or over a coil of wire. This movement changes the magnetic field of the loop of wire, which, in turn,  induces a current.

So why exactly do we care about some current?

Well because it's how our credit cards work or course! And we all need those cute new shoes. In the credit card machine, there is a loop of wire. When the card, which has a strip of magnets, moves over the wire, it changes the magnetic field and induces a current. This current acts as a signal and tells the computer the information on your card. 

Electromagnetic induction also controls stop lights, metal detectors, and helps work your electric guitar.

KEEP ROCKING PHYSICISTS 

Then we rocked even harder. We road all the way into MOTORS!

By attaching two paperclips to a battery using a rubber-band you can create the base. You then attach a magnet to the top of the battery (get ready). Then coil some copper wire and (be) extra careful to not lose any limbs, shave off the tops of the sides of the wire so the current can travel. Then carefully place the coil in the paper clips and let it spin.

VOILA! You have yourself a motor. BUT WAIT. SERIOUSLY. How is this possible?

The battery produced electrons that flowed through the copper wire, which, in turn, reacted to the magnetic field surrounding the magnet

The paper clips acted as conductors and kept the coiled wire supported

The motor turned because the current carrying wire felt a force from the magnetic field

Oh hey look... it's me..

Transformers were the final thing we learned about. Transformers step-up or step-down voltage. They have a primary and secondary coil (Or a first and a second for those of us who don't like big words). In the primary and secondary coils the more loops of wire you have the more voltage is induced.  

But transformers are picky and only use AC current because without a change in the magnetic field, no voltage will be induced.




 :)   :)   :)

Believe it or not, I really enjoyed this unit. I felt like I learned the most about how the world works, and the practical applications of Physics in this unit. The building of the motor and the field trips to see the coils of wire in front of stop lights really made this unit seem important and relevant. 

My effort, for the most part, was steady. I feel apart with this final blog post (sorry Mrs. Lawrence, sorry physics people of the world). But I assure you it wasn't for lack of enjoyment. My attitude towards Physics remains positive and I have been pleasantly surprised by how much I have come to enjoy the class. 

I still can't really believe this is our last unit, it feels like only yesterday I was hating science and trying to avoid taking the dreaded Physics class. This Unit Blog post was a shaky end to what I believe has become a solid year of learning and improvement. I am proud of what I have learned this year and hope you (yes even you readers who have no idea why I'm putting all of this on a blog) can see that!

Keep that motor runnin'

... head out on the highway?

Oh c'mon, that song's a classic! Well anyways..

In class these past few days we've been learning about motors and we finally got a chance to make one!

By attaching two paperclips to a battery using a rubber-band we created the base. We attached a magnet to the top of the battery (get ready). We then coiled some copper wire and being extra careful to not lose any limbs, shaved off the tops of the sides of the wire so the current could travel. Then carefully placing the coil in the paper clips we let it spin, watching as the magnet kept it in rotation. But wait.. how was any of this possible?

The battery produced electrons that flowed through the copper wire, which, in turn, reacted to the magnetic field surrounding the magnet

 The paper clips acted as conductors and kept the coiled wire supported

The motor turned because the current carrying wire felt a force from the magnetic field

Now this may all seem kinda pointless, I mean, a spinning wire is great and all but how can it help us have easier lives?

Well if you attached fan blades to the sides of the spinning wire you'd have a fan, attach wheels and you've got a car. Now that's some physics I couldn't do without!

Wait... WHAT? (Magnetism resource)

I remember in class when we talked about how the iron in cereal could be drawn out by magnets. Naturally I just had to look that up and see if it was true. Not only does this guy prove that theory, he also goes on to show how we can use magnetism to find metal in all kinds of things. In addition to his experiments he talks a bit about different kinds of magnets and their levels of "attraction". This video blew my mind on so many different levels. Like the fact there was iron in the ink our dollar bills are printed with and therefore even they are attracted to magnets? CRAZY.

Holy Bananas! (Unit Blog Reflection)

Holy Bananas this was a long unit! And boy was it fully charged and filled with energy!

It all started with charges.

Charges are passed along but never lost

Opposite charges attract each other

 like charges repel each other

 There are three ways to charge an object: by direct contact, friction, or induction.

We can use these nifty ways to explain why our hair sticks up after we pull on a sweater (other than: because my hair hates me).

The sweater rubs against your hair when you pull it over your head and steals electrons (that little thief). The sweater becomes negatively charged and the hair becomes positively charged. Because the positive charges want to repel each other (like a brother and sister fighting over the last oreo), your hair stands up in an effort to get away from itself.

And then things really get crackling.

It’s time for lightning (no, not grease lightning you broadway buffs.)

Lightning is created when friction charges the clouds. The ground is positive and the clouds are negative. The clouds and the ground will attract each other enough that a lightning strike occurs.

            *And lightning doesn’t go down like we see it, it actually goes up!

And those funky things called lightning rods? Yeah, they don’t actually attract lightning, charges just like to gather on pointy things so if the lightning strikes it will want to go there.

And from there we hopped on the wagon and found our way to Coulombs law

Coulombs law relates electrical force and distance

                        F=k (q1q2/d^2)

Then like a current through metal we zapped our way to Conductors and Insulators

A conductor is a material through which electrical charge can travel.

(like metal!)

An Insulator is a material that is a poor conductor of electricity

This half of the unit started out with a little thing called current, which is the flow of electric charge. The rate at which these particles flow is measured in amperes. One ampere is equal to one coulomb or charge per second.

                                    *Remember: Coulombs are the standard unit of charge

Generators and batteries can work to move these particles and separate opposite charges, therefore creating a difference in voltage.

                                    *Voltage=potential

                                                Voltage is measured in volts

It is also key to remember that charges flow through a circuit and that voltage is applied across.

But wait, there’s a new man on the workforce: Electrical Shielding.

BUT

We can only talk about shielding after we talk about electric fields

An Electric Field is the area around a charge that can affect another charge

* the lines on an Electric Field determine its strength, the closer the lines are to one another the stronger the field.

Phew, now we can get to the shields and medieval jousting. Wait… these aren’t those kinds of shields… darnit.

These shields, the electric brand, protect a negative charge from feeling any force when it is surrounded by positive charges because the positive charges repel one another.

That nifty concept is why all of our electronics are in metal cases. So the delicate balance of charges isn’t upset by your static-y sweater, metal casings act as electric shields.

Bum Bum Bum. Let’s talk about relationships. Nooo, not the awkward high school ones, ut the relationship between Resistance, Current, and Voltage.

It’s a love-hate triangle.

The labs from this unit taught us that current and voltage love one another, they’re directly proportional, whereas resistance and current, they don’t like each other as much, they like to go in different directions and are inversely proportional.

Or.

I=V/R

And if all those letters weren’t confusing enough, we hopped right into DC and AC current

DC stands for Direct Current

AC Stands for Alternating Current

This unit was a struggle for me, I missed a few days due to sickness and that really hurt me. I’ve kept up with my homework but I think coming in a few mornings a week would really benefit my grade. I did, however, find this unit interesting and I felt like I learned a lot about the world around me. All in all I faced some challenges and I didn’t effectively handle them. Next unit I will work to keep up not only with homework, but with general understanding as well.  

It's Electric!

Whoa there New York City! We all know Times Square has some crazy lights, but even those go out sometimes which is why it is so important that they are wired in parallel circuits! Parallel circuits allow different screens to be unplugged or shut off without having to shut off every light or appliance they are connected too. Could you imagine having to shut down all the lights in Times Square just to change the light bulb in a restaurant?

The Little Engine that Could

The Little Engine that Could

 Yep, it’s the name of a children’s book, but it’s also how Kat and I will fondly remember our mousetrap car.

 First: A few nifty things about our little engine - She came in last place with a time of 19.98 (We’re not really sure how she managed to go so slow and still make it 5 meters but you go girl!)

 And now we get down to the real reason Mrs. Lawrence had use build cars with only a mousetrap and 5 dollars. Nope, it wasn’t to torture us or teach us the meaning of “planning beforehand”. It was all about PHYSICS! Naturally anything in physics has got to begin with Newton’s 3 laws of motion. Here’s how they each apply to the car.

 Newton’s 1st Law- this is the law of inertia which states that an object at rest will remain at rest until a force acts to move it and an object in motion will stay in motion until a force acts to stop it. Our car wanted to stay moving so all we had to do to keep it that way was decrease the forces acting to stop it, such as friction. 

Newton’s 2nd Law- this is the law of acceleration which states that acceleration is equal to fnet over mass or a= fnet/m. By making our car lighter we could increase its acceleration because mass is inversely proportional to acceleration. Much the same way if we could increase the force we could also increase the acceleration.

 Newton’s 3rd Law- this is the law of action and reaction which states that for every action there as an equal but opposite reaction. By rotating our axle backwards and winding the string tighter we knew the car would rotate faster forwards (although we didn’t demonstrate this one too well).

 Oh yeah, remember that thing called friction? It came back. We faced two different instances of friction in our building of the car, the friction the wheels had with the ground and the friction the axles had with the frame of the car. We needed to make wheels that would have enough friction with the ground to move the car forward but not so much that it caused the car to slow down. We used CD’s like many of the other groups because they seemed to have a perfect balance. To enhance this friction some groups used balloons which seemed like a great idea. The other type of friction, the one the frame had with the axles determined how easily the axle could turn within the frame. Here we wanted as little friction as possible, something we learned was not too easy to do with cardboard.

 When we were choosing wheels we first thought about using three wheels, but for the sake of balance we upgraded to 4 wheels by the end of the project. We used CD’s on every axle  Having larger wheels would move the car a longer distance but would take more time to rotate, inversely, using smaller wheels would take less time to rotate but would go a smaller distance.

 When the car was at rest it had potential energy and as it traveled that potential energy was converted into kinetic energy. Because of the law of conservation of momentum we knew that work in would equal work out. But we knew our car wasn’t as efficient as it could be because the distance it traveled did not equal the force we put in. This means we converted a lot of energy into heat.

 Our lever arm was around 7 inches. We had a lot of problems figuring out how long we wanted our lever arm to be. We wanted the lever arm to be long so the power output of our car would be higher because it would travel a longer distance. However, we found that if the lever arm was too long it wouldn’t effectively pull the string. We chose 7 inches because it pulled the car without stopping the string.

 Rotational Inertia, Rotational Velocity, and Tangential Velocity were all big factors relating to the wheels, we wanted them to have a low rotational inertia so they would spin easily but a higher rotational velocity so they would spin faster.

 Work= f x d. But the catch is that those two forces have to be parallel. We cannot calculate many of the forces in the mousetrap car because they are not parallel.

 REFLECTION

Our final design differed only in the sense that we ended up using 4 wheels instead of three. We had originally planned on using two CD’s and a record yet when we attempted to build the car it wasn’t stable enough to balance on its own so we changed the wheel structure to include four wheels.

 The major problems we encountered with our little engine were caused by the lever arm. We could not get the lever arm to attach in a solid way and it kept ending and did not, therefore, have enough force to accelerate the rope and turn the axel. We used a lot of hot glue, tape, and determination to get our lever arm stable and then reinforced it with a second metal rod to keep it straight.

 The main thing I would do to make this project more successful would be plan. Kat and I worked well as a team, but neither of us took the time to plan out when we were going to get materials and come in to work. Because of this we found ourselves working all day on Sunday to complete the project. The biggest thing I learned was the value of writing out a schedule and then sticking to it.