Radiation

Folks are working on their radiation labs, looking at the impact of distance and shielding on the intensity of radiation experienced at a location. Not surprisingly, both increased distance and shielding lowered the radiation intensity and the relationships were nicely exponential. Tomorrow, some groups will be finishing up these labs and others will be taking on a new concept - half-life. We'll use a discharging capacitor to give us a nice model of nuclear decay and use the resulting curve to examine the half-life of the capacitor.

Senior Awards

Congratulations to the seniors who received awards from the Science department. You deserve them!

Anatomy and Physiology - Ian Sotnek
Environmental Science - Melissa Edwards
Physics - Kyle Gillen
AP Biology, Honors Physics - Victor Hu

Bye Bye Seniors

Seniors left today, though they return on Wednesday for their awards ceremony. The remaining juniors are not sitting idle, however. F Block did not meet due to the modified class schedule, but C and E did take place and students began to explore the idea of radiation. We'll concentrate on the types of radiation (α, β and γ), what occurs in nuclear decay and transmutation and the lab work will center on how shielding and distance can impact radiation exposure. The labs will use NRC-certified safe materials and appropriate safety precautions will be in place, so there's no worry about folks starting to glow green or turn into one of the X-Men.

The Accuracy is Over 9000

Just Love those Lil' Avengers

This Is What I Have to Put Up With

Food for Thought

It Begins!

The past couple of days has been review and more review, so I posted silly things to keep spirits high before peopled plunged into the depths of the final exam pool. E and C had their exams today, B and F will suffer through them tomorrow.

As book collection also commences, remember that you have to hand back to me the book that you were originally issued or it counts as a lost book. I have your book forms in my room and also on my computer, so you can email me if you need the number to check before you come to class tomorrow. If you can't find your book or you've destroyed it to the point that you're ashamed to hand it in, go on Amazon.com or some other place that handles used textbooks and buy a cheap copy (make sure the condition is ok, though) to replace yours. A new book is over $80 and that is what I'll have to charge for replacement. If you don't think the book will get here before I have to turn in senior obligations, at least print out the email showing you've ordered it.

Any final questions from B and F Block, email me before 9:00 pm (doggies and I are early-to-bedders) and I'll get back to you.

This is Made of Awesome

Scientific Method... Pretty Much Like That

This Is Why I Don't Assign Them

Barreling Along

With folks actually back in school, it was time for everyone to buckle down for review. Some in C and F Blocks worked on their Magnetism test corrections, but the focus of most people's attention was on review. Remember to ask me for help with your work and if you need extra problems, blank copies of tests, etc... try and give me some head's up in advance so I can get it ready for you. Email if you need anything after school hours...

Seriously

Today was Senior Skip Day, so some of you haven't been in class for two days. Please remember that you are staring down the barrel of exams this week and I will not be showing any mercy because you haven't had enough time to review. PLEASE use your time wisely and be prepared. Finals are 10% of your year's average...

Phryday

The only blocks that had more than a handful of attendees were B and C Blocks and they worked on either final exam review (B Block) or test corrections (C Block). Senior Skip Day is Monday, so that will also keep attendance to a very low level. Hope everyone is managing time well to prepare for the upcoming finals!

Have a fun prom and stay safe!

Test Day

Well, today was exam day for Chapter 21 and I won't seen a mess of you tomorrow since E and F will be desolate because of prom dismissals. Then, seniors won't be present on Monday... guess I'll see all folks again on Tuesday. Please remember that senior exams start next week... it would be a bummer if you didn't...

Review Day

Well, for some. B Block had their formal review for tomorrow's exam during yesterday's class and worked on their magnetism lab activities during today's long block. C and F Blocks had their review and tied up loose ends for magnetism topics. F Block finished up the material for the chapter, concentrating on magnetic forces acting on charges moving through a magnetic field and current-carrying wires in magnetic fields. After a couple of tries during the day (getting interrupted every single time), I finally pulled together a review video for this chapter...

Electromagnetism

B and E Blocks in the process of finishing up their work with magnetism. E Block worked on two investigations that highlighted properties of electromagnets and permanent magnets. Students looked at how changing the number of coils affected the strength of an electromagnet and then used their magnetic field sensor to investigate properties of the magnetic field of a bar magnet. B Block will work on this lab tomorrow and used to day as review time for Thursday's exam. E Block gets their review tomorrow.

C Block conducted the same lab investigations as E Block, but also spent time with the last section of this chapter's material, which dealt with magnetic forces. You should be able to calculate the magnitude and direction of a force acting on a charged particle or current-carrying wire in a magnetic field and remember that your homework problems are due tomorrow (lab write-up not due until Friday). We'll go over last night's homework and tonight's homework tomorrow as part of the exam review.

F Block discussed the concept of electromagnetism, referring often to their lab investigation where they built and studied an electromagnet. Tomorrow, we'll hit magnetic forces, but, as discussed in class, really won't have time for a formal review. Make sure to prepare early and come to me with questions if you have issues.

Magnets and More Magnets

B and E Block concluded their book work on magnets with an overview of magnetic forces. With a 2^nd right-hand rule at our disposal, the direction of a force on a charged particle or current-carrying wire in a magnetic field could be determined and a couple of handy formulas permitted the strength of that field to be calculated. Magnetic forces can change the motion of matter and we looked at how charged particles see their motion change, as well as wires in a magnetic field. Tomorrow, B Block gets review for their exam and E Block has a lab to run. They flip responsibilities on Wednesday and everyone gets their test on Thursday.

C Block took up the topic of electromagnetism today and looked at the field strength and properties of a straight current-carrying wire, a looped wire, a solenoid and an electromagnet. The more loops/unit area, the greater the field strength and the larger the current, the stronger the field. We examined the field properties of a solenoid with a magnetic field sensor and compass to see that it did resemble that of a bar magnet and that field strength and direction varied based on location around or in the solenoid. Tomorrow's lab will let you make an electromagnet and investigate its properties, as well as look at the magnetic field of a bar magnet. Wednesday will be the last bit of material for this chapter, but there won't be time for a formal review. The review sheet is up on Edline and there is plenty of time to ask questions of me during tomorrow's lab.

F Block began their discussion of magnetism today, building on last week's lab investigations. Those activities let folks look at permanent magnets and electromagnets and we got into some detail about the permanent magnets today in class. Be very clear about which pole combinations produce which types of forces, be able to interpret the direction of magnetic field lines, describe how a simple compass works and discuss properties of Earth's magnetic field. Tomorrow, we hit electromagnetism and Wednesday will be magnetic forces. As for C Block, review time is being curtailed, so make sure to manage time wisely and make sure to get any extra help you need before Thursday's exam.

Kicking Back

Since the majority of the school was away on the band trip to Six Flags, not a lot of new learning got accomplished in class. B and E Blocks (those that were present) took their Chapter 19-20 exam and attendees in C and F Blocks worked on correcting their tests. On Monday, its back to the grindstone with more on magnetism.

The Cutest Thing...

Magnets

C Block started with magnetism today, looking at the nature of magnetic fields and forces and relating that to Earth's magnetic field. You should be able to determine the direction of field lines for a magnet, know which pole arrangement generates attractive vs. repelling forces, understand that magnets always exist as dipoles and that Earth's magnetic field resembles, to a degree, that of a bar magnet. Since the north pole of a magnet points towards another magnet's south pole, the north end of a compass needle points towards Earth's magnetic south pole. Geographic north approximates magnetic south and vice versa. We discussed the variable nature of Earth's magnetic field over time and how scientists believe Earth's magnetic field is maintained. Those moving charged particles in our molten core is a nice segue-way into tomorrow's discussion of electromagnetism.

B and E Blocks conquered electromagnetism today in class. A current-carrying wire generates a magnetic field whose field lines make concentric circles around the wire. If a stronger magnet is needed, for the same current, looping the wire will suffice and the more loops/unit area, the stronger the magnetic field. Multiple loops of wire make what is called a solenoid and its magnetic field is very much like that of a bar magnet. Adding an iron core to the solenoid creates a true electromagnet, and its field strength is greatly increased over an air-core solenoid. On Monday, we'll take up the idea of how those magnetic fields make forces that interact with other pieces of wire or charged particles.

F Block conducted two laboratory investigations on magnetism. One looked at the relationship between the number of loops of wire around an iron nail and the strength of the generated magnetic field. The second looked at the properties of the magnetic field across the body of a bar magnet and at a distance from the magnetic poles. For electromagnets, the number of loops is directly related to magnet strength and your graph produced an nice linear relationship between number of winds and magnitude of magnetic field. You could use that relationship to predict how many loops you would need to create a magnet of a specific field strength and that is what a manufacturer would do at a factory. For the bar magnet, field strength increased as you approached the magnet and decreased as you moved away from the magnet. Across the body of the magnet, the field strength was highest at the poles (though of opposite signs) and decreases as we moved towards the middle of the magnet, where the direction of the field flipped. You conclusion should offer explanations for these results and the first section of Chapter 21 is a good place to look.

Moving On To Magnets

C and F Blocks had their last exam for the electricity unit today and jump on the magnetic bandwagon tomorrow. F Block will be working on a lab that focuses on both permanent magnets and electromagnets, which we'll discuss in class during this chapter and C Block will have their discussion about permanent magnets.

That's what B and E Blocks did today. We looked at the nature of magnets, magnetic forces and fields during lecture and spent time discussing properties of permanent magnets. Tomorrow, the focus will be electromagnets. Both types of magnets generate forces and fields and are generated by moving electric charges. However, electromagnets have an "off" switch and permanent magnets do not. The lodestone we examined today will remain magnetic unless some extreme event occurs, such as extreme heat or a strong physical blow. Electromagnets can be turned on and off by initiating or eliminating a current source and their strength can be modified by modifying factors such as the size of the current, the number of coils of wire making the magnet and the core that lies within those coils. All topics for tomorrow...

Big Ol' Review Day

C/F Blocks have their Chapters 19-20 exam tomorrow and B/E Blocks have their exam on Friday. Regardless, today was review day for everyone. We walked through the chapters highlighting the relevant information and skills that you could be asked to demonstrate on the test and, if you weren't here, there are a couple of videos below that do the same thing. Have your book out and follow along. Tomorrow, B/E Blocks begin their discussion of magnetism, which C/F Blocks will hit on Thursday.

Lots More Circuits

C Block jumped into parallel circuits today and used their lab data to illustrate our discussion. In parallel circuits, the potential difference in each branch is the same, but the current through each branch is different. It is flip-flopped for series circuits, so make sure you are very clear which pattern corresponds to which circuit type. Adding more resistors to series circuits increases overall resistance, but it decreases equivalent resistance for parallel circuits. The problems you have for homework should help you work out the math bit and some of the items will give you practice contrasting properties of series and parallel circuits. We'll go over this tomorrow before starting our review for Wednesday's exam.

E Block reviewed the concept of combination circuits and then worked additional practice with that circuit type. F Block was introduced to combination circuits and is getting their first practice with them tonight for homework. We'll look over these tomorrow before starting our test review. The B and E Block exam has been postponed until Friday, but we will be starting with Magnetism in the meantime, so don't forget to to study on Thursday night! Today, B Block worked on their series and parallel circuits lab, which should have been a good opportunity to practice practice what you've already covered about those circuit types. We'll have a general review tomorrow and go over your combination circuit homework problem, so have those labs ready to hand in when you get to class.

Types of Circuits

B and E worked through solving for equivalent resistance, equivalent current and current/potential difference across each load for combination circuits. Remember to resolve equivalent resistances for the smallest unit in your circuit, then work backwards towards larger and larger combinations until you've tackled the circuit as a whole. If I get time, I'll post a video working through a combination circuit for you to check out if you have trouble with your homework problem.

F Block took on the topic of parallel circuits and contrasted them with series arrangements. For parallel circuits, the potential difference across each resistor is the same, but the current varies because of the differing resistances. Adding resistors decreases the equivalent resistance and increases the overall current, so overloading a parallel circuit is a dangerous thing to do owing to the heat production from the higher current. Make sure you can solve problems with parallel circuits, determining the values for equivalent resistance in the circuit, overall current, current/potential difference across individual resistors. We'll go over this on Monday before taking a look at combination circuits.

C Block worked on a lab that contrasted series and parallel circuits. Folks examined patters of current and potential difference in circuits when loads are arranged in series (which we've already discussed) and parallel (which we'll hit Monday). You should have the background to analyze your series circuit information already, but a look in the book will fill in the gaps for the parallel circuits for your write-ups. We'll go over those as part of our discussion on parallel circuits.

Have a good weekend!

Let's Hope He Doesn't Take Physics

Circuits Galore

B Block discussed the nature of series circuits today, building on yesterday's general overview. We looked at features of series circuits and the patterns of current and voltage for each load in the circuit. For series circuits, the equivalent resistance is the sum of the resistors, the current is the same through each resistor and the potential difference across each resistor varies based on size of the individual resistance. Tomorrow, we'll compare this with parallel circuits and see something quite different.

C Block and F Block began a discussion of circuits today, getting a taste for the structure and function of circuits, the usefulness of schematic diagrams, the difference between open and closed circuits, the danger of short circuits and how functions, circuit breakers and GFI's act as emergency switches to open a circuit in a dangerous situation. Tomorrow' we'll break apart the basic types of circuits to study individually. We'll begin with series circuits, then move to parallel. Finally, we'll combine the types to look at more complex circuit configurations.

E Block worked on their series and parallel circuit lab. Both configurations were built and patterns for current and potential difference across resistors was examined. For series circuits, folks had some predictions based on yesterday's work in class, but parallel circuits won't be covered until tomorrow, so brain power had to be expended to evaluate those results for meaningful patterns. We'll go over these in class before hitting the details of parallel circuits tomorrow in class.

Electric Circuits

C Block finished up the last bit of Chapter 19 material today, which focused on electrical power. Remember that power is a rate function and can be approached from the angle of rate of energy conversion or rate of work being done. We looked at the consequences of delivering a specified power at high current or high voltage and how those delivery methods impacted how much power was dissipated purely as heat. Make sure you understand I²R loss or Joule heating and why that is not appropriate for many applications. That's why power companies minimize the problem by delivering power at high voltages and reducing the amount of usable energy lost to heat.

B Block started in with electric circuits today. Folks examined the nature of circuits, the role of switches, the consequences of a short circuit and the value of using a schematic diagram. Tomorrow, we'll examine a specific type of circuit - the series circuit - and how to analyze its function using Ohm's Law and the circuit's equivalent resistance. That's what E Block did in class today. Series circuits force charges to pass through every load in sequence and no load may be skipped. A problem with a load can cause the entire circuit to open so no load functions. For series circuits, therefore, the resistance charges experience is the sum of every individual resistance for the loads. The R_eq is larger than the value of the largest resistance in the circuit. Also, since charges cannot pile up in the circuit, they must flow at the same rate through the entire circuit, so the current through each load is identical. However, charges must use different amounts of energy to achieve this rate of motion as they pass through loads of varying resistances. The potential difference across each load will differ and reflect this property of series circuits. Tomorrow - parallel circuits!

F Block conducted their lab on Ohm's Law, examining ohmic resistors, a non-ohmic light bulb and an LED. The resistors demonstrated a nice linear relationship when V and I were measured and graphed, with the slope of the line being the value of the resistor. The light bulb showed different levels of resistance at different voltages and the LED permitted charge flow in a single direction only. Diodes function to direct charge motion, but resistors function to set the value for current. We'll explore this more when we move through the Circuits chapter, which starts tomorrow.