Circuits

This week in Physics we learned more about Electric Current, Resistance, and Power.  I learned that when you measure voltage, you have to make a path so you must measure across.  When you measure current, you must break the past, so you have to break the path.  Voltage is the electric potential difference between 2 points and is measured across what you are trying to measure (making a bridge).  Current through is when the current will flow through the multimeter "like water" arranged in path before the object you are going to measure.  A voltmeter makes a new path, an ammeter measures the current, breaking the path, and an ohmeter measures resistance out of the circuit.  A series circuit is one path.  It is the sum of the voltage drop across each resistor and it will equal to the total from the voltage source. On the other hand, a parallel circuit is a multi path circuit.  Each resistor has the same amount of voltage and is not broken down into components.  I related this to a type of voltage source used to charge multiple things at once.  I'm not exactly sure if this is the right concept but I think that because this voltage source is connected to the original source, it creates a parallel circuit. Because multiple things can charge at once, it gives the same amount of voltage making it a parallel circuit.

Saving Electricity

This week in Physics we had to bring in our electric bills into class.  We then talked about our electricity and how much we use it.  The amount we pay shows us whether or not we use a lot of electricity.  Compared to one of my friend's electricity bills, the amount my family pays was low, but, compared to another friend, my electricity bill was high!  My family pays about $360 a month for electricity.  The person who's electricity bill was lower than mine only pays about $16 a month.  But, this is because they have solar panels on their roof.  We learned a little bit about the solar panels and how it saves us money.  It uses the sun's energy to create energy we need to run the electric utilities in our house.  The use of the sun isn't limited at all! Electric bills have been going up recently though because Hawaiian Electric paid borrowed money in advanced, thinking they would get their money back over the months, but since this new solar panel technology has come out, people pay much less for their electricity so Hawaiian Electric has raised their prices and taxes for those who do not have any panels on their roofs.  My family is currently looking into putting some panels on our roof so we won't have to pay as much.  But for now, I have challenged myself to try and save electricity.  I have been unplugging things from the walls when I am not charging them and taking shorter showers and turning off the lights when I'm not using it.  Hopefully this works and my parents won't have to pay as much this month!

Direct Current

This week in Physics we learned about Electric Current, Resistance, and Power.  We learned a couple of basic definitions of this unit: voltage, current, and resistance.  A voltage is the amount of work that each charge will do as it goes through the circuit; it can also be thought of as the amount of push on the charges.  A current is the number of charges passing a point per second; also know as the rate of flow of charge (I).  Resistance is the opposition to flow of charge; also any application that asks the charge to do and will slow it down. One thing I really understood this week was about circuits.  We learned that for a system to work, there needs it needs to be in a circuit.  Also, without potential difference (voltages), charges will not flow.  The different types of circuits are direct (DC) and alternating (AC).  A direct circuit makes charges flow one way.  An example I related this to was my laptop charger.  As I was writing this blogpost, my computer was about to die, so I grabbed my laptop charge and connected it to the outlet in the wall.  Because of the direct current, my laptop is able to charge back to 100% battery. Thank God for laptop chargers!`

Capacitance and Voltage

This week in Physics we learned about capacitance.  A capacitance is energy stored.  It is the storage of lots of voltage but not a great deal of charge.  Some examples of of capacitance are keyboards and touch screen devices.  Let me try to relate my typing on this computer to this unit of physics that we are learning. The equation of a capacitance is C=(EA)/d [where C is the capacitance, E is the epsilon or permitivity of (air) free space, A is the area of plates (meters squared), and d is the distance between the plates (meter).  Every time I hit a key to type a letter, the capacitance changes because the distance between the two plates change.  The units of capacitance are Coulombs (Q)/Volts (V), also known as Farads (F).  This is what I learned this about in Physics this week.

"It's Electric...Boogie Woogie Woogie"

This week in Physics, we learned a little bit about Electric Potential and Electric Potential Energy. Electric Potential Energy is the stored energy of a charged object in an electric potential field.  Its unites are in Joules.  During our lesson, Mr. Blake over and over said that Electric Potential DOES NOT equal Electric Potential Energy.  But, he did say that Electric Potential DOES equal Electric Potential Energy/Charge.  Electric Potential is also known as "Electric Potential Difference".  This unit of Electric Potential is in Volts (Voltages) because it is Joules/Coulombs.  Basically, Electric Potential is how much energy you get per unit of charge.  This is all I know of this unit so far and hopefully this week I get a better understanding of it!

"Opposites Attract"

This week in Physics, we kept learning about our unit of Electric Charges.  As I've said in my last blogpost, opposite charges attract while similar charges repel.  I've related this concept to my relationships with people.  Although relationships don't specifically deal with charges, it has the same idea of opposites attracting.  For example, me and my boyfriend are not really alike.  He does different sports than I do. He is extremely social. I am not. He enjoys speech, and I definitely do not like speech. He is always confident in himself, and I lack in that area of self-confidence.  Although we are not similar, we are attracted to each other. Another example would be me and my friends.  In our entire group, everyone is uniquely different.  Some of us play similar sports and have a few things in common, but we are not entirely alike.  That is a reason why we are attracted to each other.  I kind of enjoyed learning about this unit in Physics because I learned the real reason why things are attracted to each other and how opposite charges attract.  I will not ever forget this concept in Physics because of the slogan, "Opposites Attract".

MAGNETSSS!

This week we learned about Electric Charges, Forces, and Fields.  One of the basic concepts of this unit (also something I understand pretty well) was about the electric charges.  Their are 3 types of charges: positive (protons), negative (electrons), and no charge (neutron). Protons are represented by a +1.  Electrons are represented by a -1. Neutrons have no charge, so their symbol is 0.  According to the Charge Force Law, like charges will repel each other and unlike charges will attract each other.  For example, if 2 object are both negative, they will repel each other.  If one is positive and one is negative they will attract.  If two objects are neutral, they will have no effect. Also, if one object is either positive or negative and the second object is neutral, they will attract.  I related this concept of physics to my refrigerator door.  Everyday I go in and out of the fridge to get food to eat.  I see the calendar on the door everyday as I open and close the door.  The calendar is hanging from a magnet which is on top the fridge door.  I made the connection from the door and the magnet to this physics concept of electric charges.  Because the magnet is able to stick to the fridge door means that they have opposite charges.  The magnet sticks to the fridge door because it is attracted to it. It all makes sense now!!

"What I learned in 1st Semester"

This semester I learned a lot!! The first unit we learned about was Kinematics (1-dimensional and 2-dimensional).  I learned that kinematics is the study of motion.  This is the basics of physics.  After we learned about kinematics, we learned a little bit of graphing that goes deals with kinematics.  The next unit was Forces and Motions. In this unit I learned Newton's 1st, 2nd, and 3rd laws of motion.  I learned that a newton is in units of kg m/s^2 and that weight = mg. Also in this unit we learned about pulleys and because it has one string, that means there is one tension.  Momentum was the next unit we learned about.  I learned taht momentum is a vector that is calculated by multiplying mass times its velocity (units: kg m/s). The law of conservation of momentum is that momentum cannot be created nor destroyed, it can only change forms, so therefore, momentum in equals momentum out.  Similar to this law of conservation, I learned about the law of conservation of energy which basically stated that energy in equals energy out, in the our unit of Work and Energy.  I learned much information this semester and many equations.  All this information and knowledge I learned was written down in my physics notebook so that I will never forget. :)

DO WORK SON!

This week we learned about work and energy.  Work is activity involving effort to achieve a result.  To find work you can multiply the force on the object by its displacement.  The units of energy used is Nm, also known as Joules.  Work = the change in energy.  According the the law of energy, energry cannot be created nor destroyed; it can only change forms (in an isolated system).  The energry of position is an object's potential energy.  You can calculate an object's gravitational potential by multiplying its mass by the gravity by its height.  After learning about work and energy, it reminded me of this weekend.  My mom and I were sitting at the table and she asked me to pass her my pencil case.  I was too lazy to pick it up and hand it to her, so I slid it across the table.  I pushed my pencil case about 1/2 a meter.  If it took a force of 3 N to push the pencil case, the work I would being doing would be 1.5 Joules.  I'm glad I got to learn about Work and Energy this past week, so now I know how to what work and energy is and how it is applied.

Egg Drop Lab...SUCCESS :)

This week we did our Egg Drop Labs! I found this to be a very fun, interesting, and yet kind of challenging experiment to do because Kawai, Lydia, and I weren't 100% sure if our egg was going to survive! We used a 33 cm shoebox as our device.  We glued lots of cotton balls to the inner surrounding walls of the box.  After the box was all cushion-ized, we took a smaller box and glued cotton balls into it. This small box would be the object that held our egg in place.  When we received the egg, we wrapped it in black felt and taped it so that it was secure.  Once we were finished wrapping our egg in felt, we placed it into the small box and closed it.  We then put bubble wrap between the cotton balls on the inside of the bigger box and the bottom of the smaller box. We taped the small box to the shoebox.  We closed the lid of the shoebox and taped it so that it would not fly off during the drop.  If you watch the first video above, it shows how our egg was dropped.  In the second video, you can see that our egg survived the fall!  The reason why our egg survived was mainly due to the cotton balls.  We chose to use cotton balls because we knew that it would absorb the shock of the fall.  I really liked this lab because it was like a mini project and there was a little bit of suspense right before our egg was dropped.  I also liked seeing the various devices that the other groups created.  After all the eggs were dropped I came to realize that this lab wasn't as challenging as we made it to be.  One group had a very simple yet effective device.  They had three sponges.  They cut a whole in the middle of one of the sponges just enough for the egg to fit in.  After placing the egg in the whole, the surrounded the sides with the other two sponges (one on each side).  They then rubber-banded the three sponges together and dropped it! To me, this was the smartest device of them all because it was light in weight and it had LOTS of cushioning which would make the contact time of the sponge and the ground a lot longer than a shoebox would.  But, in the end, I'm just glad our device worked and our egg survived.:)

MOMENTUM!

I finally understand what momentum is and how you can calculate it.  Like I've mentioned in previous posts, momentum is calculated by multiplying the mass of the object times its velocity.  For example, the picture above is of my eraser.  Let's say that this eraser was 2 kg (a very heavy eraser).  If I were to throw the eraser and the velocity it was moving at was 2 m/s, I could then calculate the momentum of this eraser.  The momentum would be 4 kg m/s because I multiplied the mass by its velocity.  We use momentum in our everyday lives.  I am glad I know how to calculate momentum now!  I'm glad I learn something new in Physics everyday :)

More Stuff on Momentum

This week in Physics, we learned more about momentum.  On Wednesday we were suppose to do a lab about collisions to help us learn more about momentum, but I was sick on that day, so I'm not exactly sure how to explain anything about collision.  But, I can explain a little bit about the Law of Conservation of Momentum.  This law states that momentum cannot be created nor destroyed, it only changes forms, momentum in then will equal momentum out.  From this week, I learned the momentum is a vector/  To find momentum you must multiply the mass of an objec by its velocity (P = mv).  The units we use in this equation are kg m/s.  I also learned about impulse and how it contributes to momentum and force.  Impulse is the change in momentum (delta P).  This is then plugged into the equation of force, which equals the change in momentum/change in time (delta P/delta T).  This is what I learned this week in Physics.

My Thoughts on Momentum

Our next chapter we will be covering is momentum.  In order to begin this new unit, Mr. Blake wanted ut to make our blogpost about either what we think momentum is using our own personal knowledge, or doing research on it.  Because I don't really know anything about momentum, I did some research.  I first looked up the definition of momentum and dictionary.com gave me: "the force or speed of movement of an object".  I then looked in our textbooks for more answers.  The first thing in the textbook about momentum was linear momentum.  Linear momentum is defined as the product of the mass and velocity of an object.  The example it gave me basically said that if you catch a fast enough light-weighted ball and compare it to catching a heavy, slow moving ball, then you will move with the same speed.  This helped me to learn a little about momentum.  Before this small research, I only knew how to use the term "momentum" in speaking, but I never really knew what it was.  Now I know something about it!

Friction!

This weekend, I had to move a couple of these big boxes from my living room into the office.  My living room floor is covered in carpet.  The boxes were way to heavy to carry by myself, so I decided to push them.  Although I am not exactly sure what the precise amount of the forces acting upon the boxes was, I do know that the forces that were acting upon it was weight (mg), normal force, the force I used to push the boxes, and also friction.  There was friction because the boxes were on top of the carpet, causing an opposing motion to my force exerted on the boxes.  Many times in the past I have pushed objects across floors, but I never really thought of why it was harder to push things across certain types of surfaces.  I now know that friction is an important part of motion.

Force

In Physics, we learned about force.  A force is a push or a pull.  This week we learned  about how forces affect objects.  In learning this, we used free body diagrams.  In the picture above, there is my contact solution box resting on my dresser.  This box can stay at rest because it is balanced and no outside forces are acting upon it.  The forces which make this object balanced are its own weight (mg) pushing down and the normal force (N) pushing up.  These two forces equally pushing against each other is what makes the object balanced.  Right next to my picture of the box at rest on the dresser, there is my free body diagram.  Free body diagrams (FBD) helps us to see the forces and how they are affecting the object.  There are two arrows in my FBD, which are the weight and the normal force.  This is another way of explaining how the object is balanced.

Newton's 1st Law of Motion

This week, we learned about forces and motions.  One thing I remembered the most from this week's lesson was Newton's 1st Law of Motion.  This law states that "objects in motion [at rest] will tend to stay in motion [at rest] unless acted upon by an outside, unbalanced force".  This weekend I went to support our football boys at their game against Punahou.  When the quarterback threw the ball in the air, it reminded me of the Newton's 1st Law of Motion.  After watching the ball being thrown, seconds later, it landed in another players' hands.  Seeing this, I thought to myself, "Wait a second...objects in motion don't always tend to stay in motion!" Instead of the ball staying in motion in the air forever, it dropped.  Confused, I rethought the situation over.  I then realized my mistake...I had forgotten about the outside, unbalanced force and how it affects objects in motion.  So, it was because of gravity that the ball dropped and eventually stop moving.  Gravity is an example of an outside, unbalanced force mentioned in Newton's 1st Law of Motion.  After the game on Saturday night, I was glad that I was able to incorporate some Physics into the game because I know that when I can relate things to real life situations, I tend to learn better.
...by the way, Congrats on the win Warriors! :)

Extra Credit

This is proof that my dad viewed my blog. :)

2-Dimensional Kinematics

In class, Mr. Blake taught us the BUREKU Technique.  Mr. Blake doesn't like diagonal lines, so in order to find the velocity of the diagonal line he must...wataaaaa!...break the diagonal line into a horizontal and vertical line.  The BUREKU Technique makes life much, much easier.  We also learned about SOH-CAH-TOA this week.  SOH-CAH-TOA is used to find the hypotenuse, opposite, or adjacent variables of a triangle.  As you can see on my picture, there is a triangle with the labeled parts.  The hypotenuse is the diagonal line of the triangle, the adjacent line is the line that is inline with the angle given (marked with a curved line), and the opposite line is the line opposite of this same angle.  To figure out lengths of these lines, we are given 3 different equations:
SOH- Sin = Opposite/Hypotenuse
CAH- Cos = Adjacent/Hypotenuse
TOA- Tan = Opposite/Adjacent
You must plug in the right equations to fit the situation to find your values.  These are some ways to solve for 2-Dimensional Kinematics!

Equivalent Vectors

In Physics, we use vectors as measurements.  A vector quantity has magnitude (size & unit) and direction (N, E, S, W).  Another way of remembering vectors is "how much and which way".  Velocity is an example of a vector because it tells how fast an object is going and in which direction.  In the picture above, there is two columns; one of an example of an equivalent vectors, and the other is an example of a non-equivalent vectors.  The reason the left column arrows are equivalent to each other is because they both are pointing North and are relatively the same size.  In the right column, we can tell that these two arrows are not equivalent vectors because first of all, they are pointing in two different directions, and second of all, the green arrow is shorter than the pink arrow.  A vector is only equivalent to another vector when both its' magnitude and direction are the same.

What Goes Up, Must Come Down

This week, we did the Ball Toss Lab.  When Coach Chris showed us an example of what we were doing in the lab, he took a volleyball and threw it up 2 meters and then caught it at the same level he threw it from.  This reminded me of when my friends and I were trying to capture a picture of us jumping together. Coach Chris taught us that when an object is thrown in the air, its velocity goes slow, fast, stop, slow, fast.  This weekend I was just looking over my pictures and I remembered when we were all jumping in the air! It made me think that when we were jumping that we started off slow, then sped up as we got to the top, and then stopped in the air, and as we came down it went slow, and then fast as we hit the floor. This Ball Toss Lab helped me realize that whenever something goes up, it must come down, but when it is in the air, it has different velocities.