The Physics of Electricity and Magnetism Welcome Back and a Quick Electricity Review 9-12 Science Std: Phys 5e, i, j, m

First, a quick look at the schedule MonTueWedThuFri 1/121/131/141/151/16 1/191/201/211/221/23 Welcome Back and a Quick Review Magnets making electricity Activity – Making electricity with a magnet and measuring it Entropy or how to measure disorder End of All of Physics Topics Review and select project topics Martin Luther King Jr’s Birthday No School End of Physics Project Work End of Physics Project work and select presentation order Physics Project Presentation Groups 1, 2, 3

First, a quick look at the schedule MonTueWedThuFri 1/261/271/281/291/30 2/22/32/42/52/6 Physics Project Presentation Groups 4, 5, 6 Physics Project Presentation Groups 7, 8, 9 End of Physics Exam Review Physics ExamMake up Physics Exam and Exam Review Final Exam Review - Geology Final Exam Review - Physics Final Exams (short day) Periods 1, 4 Final Exams (short day) Periods 2, 5 Final Exams (short day) Periods 3, 6

First, a quick look at the schedule So, here are the important dates for you…… Present Physics Projects: 1/23, 1/26, 1/27 (Fri, Mon, Tue) Physics Exam Review 1/28 (Wed) End of Physics Exam 1/29 (Thu) Makeup 1/30 (Fri) Final Exam Review 2/2-2/3 (Mon-Tue) Final Exams 2/4-2/6 (Wed-Fri) Depending on the period

So, now onto the review…… We focused on the Electrostatic Forces We started with the atom… The atom has a positively charged nucleus and negatively charged electrons going around the atom The positively charged protons and the negatively charged electrons attract each other As long as the atom has a equal number of protons and electrons, the electrical charge is balanced and there are no electrostatic forces

So, now onto the review…… We learned what happens to the atom…. If an electron leaves the atom The atom’s electrical charge is unbalanced The atom has a positive charge And the negatively charged electrons are floating around by themselves This makes free negatively charged electrons and positively charged ions

So, now onto the review…… The electrons can get pulled away for many reasons….. They can get rubbed off…. Like when we rub a balloon against our hair Or when we used the Van De Graff Generator

So, now onto the review…… The electrons can get pulled away for many reasons….. Or they can be forced off…. By having a large electric potential from a battery… Or from some other electrical power source

So, now onto the review…… But once away, electrostatic forces work on them…. Charges that are the same repel each other Opposite charges attract each other

So, now onto the review…… But once away, electrostatic forces work on them…. The amount of force attracting or repelling depends on The amount of charge….. The bigger the charge…. The bigger the force between them More Charge = More Force

So, now onto the review…… But once away, electrostatic forces work on them…. The amount of force attracting or repelling depends on The distance between the charges The closer the charges… The bigger the force between them Closer Together = More Force This is a much bigger effect than changing the sizes of the charges

So, now onto the review…… These charges create fields of force around them Not that kind of force field……….

So, now onto the review…… These charges create fields of force around them Every thing that has an electric charge puts out lines of force that attract or repel other charges A point charge puts out lines in all directions

So, now onto the review…… These charges create fields of force around them Every thing that has an electric charge puts out lines of force that attract or repel other charges A plate charged source puts out lines of force in one direction The lines of force coming from the point or the plate are called Vector Fields

So, now onto the review…… We can measure the amount of force This force is called the electric potential Or electric voltage The higher the voltage, the higher the potential It is like a ball rolling down a hill…. A small hill won’t make the ball roll fast

So, now onto the review…… We can measure the amount of force This force is called the electric potential Or electric voltage The higher the voltage, the higher the potential It is like a ball rolling down a hill…. But a big hill will really get a ball rolling…

So, now onto the review…… But the voltage is just the driving force What makes things happen is the moving charged electrons When charges move, we can measure it another way The moving charged particles is called the electrical current So it isn’t the voltage that hurts us, it is the current that we feel

So, now onto the review…… Then, we covered the 4 th state of matter…. If you remember, things come 4 different ways…. Solid Liquid Gas

So, now onto the review…… Then, we covered the 4 th state of matter…. If you remember, things come 4 different ways…. and Plasma

So, now onto the review…… Plasma is a special condition It is where you have lots of ions and electrons all floating around together all the time Because they are all mixed up, the positive and negative charge forces cancel each other But because the ions and electrons are all floating around free, plasma can easily conduct electricity

So, now onto the review…… Electrical current can make a magnetic field When an electrical current runs through a wire it creates a magnetic field You can see the field here using iron filings sprinkled around a wire

So, now onto the review…… Electrical current can make a magnetic field The shape of the magnetic field is a circle around the wire The direction of the magnetic field is shown using the right hand rule Wrap your hand around the wire with your thumb pointing in the direction of the current and your fingers show the field’s direction

So, that is what we have covered What you should remember is…… Charged particles are sources of electric fields Charged particles feel forces from the electric fields of other charges Electric fields contain energy Electric fields work in a specific direction (they are vector fields) Electric forces get bigger as the amount of charge gets bigger Electric forces get bigger as two charges get closer to each other and has a bigger effect than changing the size of the charges

So, that is what we have covered What you should remember is…… Static electric fields are caused by groups of electric charges sitting in one place Plasma is made up of ions and free electrons Plasma can conduct electricity Electric current in a wire makes a magnetic field The direction of the magnetic field is shown by the right hand rule

Now that we have finished We can finish magnetism and electricity And how magnetism affects electricity But that is for later……. And then finally how we can measure how much order is in a system