Periods 3-4, 8-9:
Please watch either alone or with a partner a Mechanical Universe video on angular momentum. You can start at the 11:00 minute mark and end at the 23:10 minute mark, where they get to the part we are interested in. Take notes as they get into the more detailed definition of angular momentum, and show some examples of conservation. Think about the how and why of a figure skater who is spinning, and how she is able to control the angular speed of the spin. A second video to then check out is on how to set up and problem solve with angular momentum. Same deal, take some notes on the setups so it helps you with some practice problems.
Practice problems are Ch. 10 #40,41,42,43 (on p. 3 of the packet). You can also talk through any issues on the last quizzam in your work groups. Check out the bug problem solution...does it make sense???
Period 5:
Please watch either alone or with a partner a Mechanical Universe video on electric circuits. This will give some additional visual examples of what a circuit is and how it works, using the rules we have seen in the lab and in class. Please watch from the 3:20 mark to the 20:10 mark. Take good notes, since we will have a brief note quiz tomorrow on what you are watching.
After checking out the video, you can get a couple partners and get a start on the conceptual questions about series and parallel circuits on the page we got Monday. Work through the circled questions on the first page. We will discuss these Thursday, and try to wrap up the basic circuit ideas so we can move into a consequence of electric currents, which is MAGNETISM! Magnetism is also pretty cool, while being a bit mysterious.
Wednesday, April 10, 2019
Tuesday, April 2, 2019
Bees use sophisticated eyesight and electric fields to find flowers with pollen
A fascinating example of electric fields for bees and flowers, that help bees seek out pollinated flowers. Check out this NY Times short article on the topic. I personally find this extremely cool. :-)
Monday, March 18, 2019
The rest of the week
Below are some things to work on Wednesday - Friday, and then get a well-deserved break before we start the last quarter!
Wednesday (3/20)
Periods 3-4, 8-9:
We're going to try to pick up as much as possible about Faraday's law of electromagnetic induction. This is one of the biggies in all of science, not just physics. It is responsible for understanding electric motors, electric generators, transformers (which make our power grid work properly), different types of stoves and amusement park rides, all the way down to how light works as an electromagnetic wave! There's a lot of applications with a relatively basic observation:
If one changes magnetic flux, flux = BA, through a conductor, voltage is induced. This induced voltage is sometimes called emf (electromotive force). It was discovered by Michael Faraday in the 1820s and 1830s.
emf = d(BA)/dt
This is a video for moving a loop of wire through a magnetic field. This is the case emf = B dA/dt. To get the essence of this phenomenon, also check out a video on what happens just by moving a piece of metal through a magnetic field...it polarizes, and can act like a battery!
In the B dA/dt packet, try the 1981 AP Problem on page 7 and the glider problem on page 8.
Period 5:
Get your data for the resistance lab. This means NOT connecting the circuit to a power supply. Try to set up all the various circuits on your breadboard, and measure the total resistance (set your multimeter to ohms, ) for series, parallel, and combinations of the two. The big goal is to look for patterns - how does the total resistance change as you put in other resistors? Does the total increase or decrease? By how much does the total resistance change as you add in more resistors? Use the data page as a guide of what each circuit should look like.
Thursday (3/21)
Periods 3-4, 8-9:
This is video for a loop falling through a magnetic field - the magnetic forces act like air friction, and with gravity we get terminal velocity! This is another case of emf = B dA/dt.
Use the example of the video to try the 1990 problem on page 9 and 'the hardest ever' on the last page.
Period 5:
Today, connect the power supply to the circuit using the short wire jumpers connected in the breadboard. Try the two experiments on the Ohm's law lab sheet. Have a fixed resistance on the breadboard and vary the voltage to measure the currents (in milliamps). Then, change the resistance on the breadboard and set the voltage to the same value each time, to see what effect resistance has on the electric current.
Friday (3/22)
Periods 3-4, 8-9:
This is a video for the second case of changing magnetic flux, where the metal loop stays still and the magnetic field changes. Physically this happens because a changing B-field induces a circulating electric field! This is the reverse of a changing E-field, due to moving charges, inducing a circulating magnetic field. Also watch this video going through an example of circulating E-fields created when there is a changing B-field.
The problems are in the new AdB/dt packet. Try the 2010 and 1978 AP problems on pages 4 and 5.
Take the past three days as far as you can in class, and we will have time to answer questions, break things down, see physical examples, synthesize and expand after spring break! We'll all figure it out! :-)
Period 5:
Be sure to complete the data collection for the two labs. When you have all the data, try the analysis questions for each lab, and take things as far as your group can. You will need to make some graphs using the chromebooks for the Ohm's law lab. We will look at the data and go through the big results after spring break!
HAVE WONDERFUL, RELAXING SPRING BREAKS!!!!!!!
Wednesday (3/20)
Periods 3-4, 8-9:
We're going to try to pick up as much as possible about Faraday's law of electromagnetic induction. This is one of the biggies in all of science, not just physics. It is responsible for understanding electric motors, electric generators, transformers (which make our power grid work properly), different types of stoves and amusement park rides, all the way down to how light works as an electromagnetic wave! There's a lot of applications with a relatively basic observation:
If one changes magnetic flux, flux = BA, through a conductor, voltage is induced. This induced voltage is sometimes called emf (electromotive force). It was discovered by Michael Faraday in the 1820s and 1830s.
emf = d(BA)/dt
This is a video for moving a loop of wire through a magnetic field. This is the case emf = B dA/dt. To get the essence of this phenomenon, also check out a video on what happens just by moving a piece of metal through a magnetic field...it polarizes, and can act like a battery!
In the B dA/dt packet, try the 1981 AP Problem on page 7 and the glider problem on page 8.
Period 5:
Get your data for the resistance lab. This means NOT connecting the circuit to a power supply. Try to set up all the various circuits on your breadboard, and measure the total resistance (set your multimeter to ohms, ) for series, parallel, and combinations of the two. The big goal is to look for patterns - how does the total resistance change as you put in other resistors? Does the total increase or decrease? By how much does the total resistance change as you add in more resistors? Use the data page as a guide of what each circuit should look like.
Thursday (3/21)
Periods 3-4, 8-9:
This is video for a loop falling through a magnetic field - the magnetic forces act like air friction, and with gravity we get terminal velocity! This is another case of emf = B dA/dt.
Use the example of the video to try the 1990 problem on page 9 and 'the hardest ever' on the last page.
Period 5:
Today, connect the power supply to the circuit using the short wire jumpers connected in the breadboard. Try the two experiments on the Ohm's law lab sheet. Have a fixed resistance on the breadboard and vary the voltage to measure the currents (in milliamps). Then, change the resistance on the breadboard and set the voltage to the same value each time, to see what effect resistance has on the electric current.
Friday (3/22)
Periods 3-4, 8-9:
This is a video for the second case of changing magnetic flux, where the metal loop stays still and the magnetic field changes. Physically this happens because a changing B-field induces a circulating electric field! This is the reverse of a changing E-field, due to moving charges, inducing a circulating magnetic field. Also watch this video going through an example of circulating E-fields created when there is a changing B-field.
The problems are in the new AdB/dt packet. Try the 2010 and 1978 AP problems on pages 4 and 5.
Take the past three days as far as you can in class, and we will have time to answer questions, break things down, see physical examples, synthesize and expand after spring break! We'll all figure it out! :-)
Period 5:
Be sure to complete the data collection for the two labs. When you have all the data, try the analysis questions for each lab, and take things as far as your group can. You will need to make some graphs using the chromebooks for the Ohm's law lab. We will look at the data and go through the big results after spring break!
HAVE WONDERFUL, RELAXING SPRING BREAKS!!!!!!!
Saturday, March 16, 2019
Back off - The College one goes to DOES NOT matter!
A really important article for all of us in the high schools - two broad studies were carried out by a mathematician and economist, where they looked over years of data for college graduates, and looked at careers, incomes, and happiness with one's life after college graduation. The results were pretty clear, that it made no difference where one went to college! Going to Harvard or Stanford does not, on average, lead to more money or more happiness than less elite colleges.
This follows other important statistics, such as teens are presently the most stressed population in our society, and by far the biggest stressor is school and our near demands that every teen must go to college if they want to have any chance at having a life worth living. And the pressures to get nothing but A's while taking 6 AP classes and being in every possible club, sport and performance, have increased stress levels, led to record levels of depression and anxiety, and record high cases of teen suicide. We must take it easier on our children, and especially on our teens!
Goals are important, hard work is important, school and learning are important. But life must still be worth living, and happiness is still something that is vital for each of us. And the statistics of this college study are an important piece of all this that we adults should take seriously.
This follows other important statistics, such as teens are presently the most stressed population in our society, and by far the biggest stressor is school and our near demands that every teen must go to college if they want to have any chance at having a life worth living. And the pressures to get nothing but A's while taking 6 AP classes and being in every possible club, sport and performance, have increased stress levels, led to record levels of depression and anxiety, and record high cases of teen suicide. We must take it easier on our children, and especially on our teens!
Goals are important, hard work is important, school and learning are important. But life must still be worth living, and happiness is still something that is vital for each of us. And the statistics of this college study are an important piece of all this that we adults should take seriously.
Tuesday, March 5, 2019
Tuesday, March 5
With apologies and frustration, I cannot join you today. Please try the following:
Period 3-4, 8-9
Complete the chart we began yesterday by checking out this introductory video on rotations. Then, check out how to find torque and equilibrium. Take some notes on the examples, and then you can break into groups to try and complete the practice problems below. Tomorrow we will get into a lab where you can see all the rotational quantities in action.
Ch. 9 #3, 5 on page 5
Ch. 10 #1, 2 on page 7
Ch. 11 #13 on page 7
Period 5
Static electricity labs should be done and turned in.
Using what we were saying about induction and polarization yesterday and last week, in small groups try and complete the first three pages of the static electricity packet. These include the vocabulary and chart of insulators and conductors for the first page, rule of electric charges for the front and back of the second page (attraction and repulsion), and charging by induction for the front and back of the third page. For extra credit, try the fourth page that deals with lightning. Feel free to use either video from the E-day (video 1, or video 2). If you try the lightning page, it will ask about the electric force between charges. There is a formula that looks and behaves like the formula we used for gravity. This is:
F = kQq/d^2
The k is a number, k = 9 x 10^9 = 9,000,000,000 (9 billion). The Q,q are symbols for electric charge, which has a unit called a coulomb, C. Notice it is divided by distance-squared, just like gravity. If charges are twize as far apart, the electric force is 2^2 or 4 times weaker, etc.
Answer keys for the packet is in the Electricity folder on our school website.
Period 3-4, 8-9
Complete the chart we began yesterday by checking out this introductory video on rotations. Then, check out how to find torque and equilibrium. Take some notes on the examples, and then you can break into groups to try and complete the practice problems below. Tomorrow we will get into a lab where you can see all the rotational quantities in action.
Ch. 9 #3, 5 on page 5
Ch. 10 #1, 2 on page 7
Ch. 11 #13 on page 7
Period 5
Static electricity labs should be done and turned in.
Using what we were saying about induction and polarization yesterday and last week, in small groups try and complete the first three pages of the static electricity packet. These include the vocabulary and chart of insulators and conductors for the first page, rule of electric charges for the front and back of the second page (attraction and repulsion), and charging by induction for the front and back of the third page. For extra credit, try the fourth page that deals with lightning. Feel free to use either video from the E-day (video 1, or video 2). If you try the lightning page, it will ask about the electric force between charges. There is a formula that looks and behaves like the formula we used for gravity. This is:
F = kQq/d^2
The k is a number, k = 9 x 10^9 = 9,000,000,000 (9 billion). The Q,q are symbols for electric charge, which has a unit called a coulomb, C. Notice it is divided by distance-squared, just like gravity. If charges are twize as far apart, the electric force is 2^2 or 4 times weaker, etc.
Answer keys for the packet is in the Electricity folder on our school website.
Monday, February 25, 2019
Monday
Periods 3-4, 8-9:
Please check out two videos on magnetism caused by electric currents. One is on Ampere's law, which will be to magnetic fields what Gauss's law is to electric fields. Focus especially on just a single straight wire, and the magnetism that circulates around the current.
The second is on the magnetic forces between two currents; since each wire with current is producing magnetism, then it is like having two magnets. Wires can attract and repel each other, depending on the direction of the current. Assume currents are positive, and we will use the 'curly right hand rule' for wires to figure out which direction the magnetism circulates.
Be sure the simulations are completed and shared. Also, lab groups can work on completing the questions if needed. We will discuss and collect Tuesday.
Period 5:
Be sure your E&M topic research is completed and shared by now, so our eBook can be completed. Also, be sure the Friday videos and questions are completed. We'll go through them tomorrow.
Today, work with a partner on the first two pages of the static electricity packet. Feel free to look up terms as needed on the first page, and if needed to look up materials on the second page. Conductors allow electricity to flow, and insulators do not allow electricity to flow.
Should you have extra time, by all means you can try to work ahead. Or, you can work on other stuff. Thanks!
Please check out two videos on magnetism caused by electric currents. One is on Ampere's law, which will be to magnetic fields what Gauss's law is to electric fields. Focus especially on just a single straight wire, and the magnetism that circulates around the current.
The second is on the magnetic forces between two currents; since each wire with current is producing magnetism, then it is like having two magnets. Wires can attract and repel each other, depending on the direction of the current. Assume currents are positive, and we will use the 'curly right hand rule' for wires to figure out which direction the magnetism circulates.
Be sure the simulations are completed and shared. Also, lab groups can work on completing the questions if needed. We will discuss and collect Tuesday.
Period 5:
Be sure your E&M topic research is completed and shared by now, so our eBook can be completed. Also, be sure the Friday videos and questions are completed. We'll go through them tomorrow.
Today, work with a partner on the first two pages of the static electricity packet. Feel free to look up terms as needed on the first page, and if needed to look up materials on the second page. Conductors allow electricity to flow, and insulators do not allow electricity to flow.
Should you have extra time, by all means you can try to work ahead. Or, you can work on other stuff. Thanks!
Tuesday, February 19, 2019
eLearning Friday!
Below are links to use for Friday's virtual class. Do these when convenient, and be sure to email or share your work with Doc V.
For Attendance:
*For the Chem/Phys classes: got word that no name appears for one of the two periods - this should not be an issue for attendance, and is a feature for how the school sets up the gradebook. Even if it shows up next week, it will not be a problem correcting it!
Period 3-4, 8-9:
For magnetic forces, F = qv x B, try two ActivPhysics simulations. These are set up as lessons, so just follow along and type up your responses in a Google Doc that is shared with Doc V at vondracekm@eths202.org.
- Go to Part VI on the home page, which is Electricity & Magnetism. Try 13.4, Magnetic Force on a Particle. You may have to click to enable Adobe Flash Player, but this was working on my Chromebook. Click on the box on the right side to open the simulation, and follow the various questions that will require you to run the simulation. Respond to questions, and write out all responses, explanations, and descriptions that are asked for.
- Then try 13.7, Mass Spectrometer. Same deal, use the simulation of a mass spectrometer to determine isotopes of different elements. Type up responses in your Google Doc, and share both when finished.
For each of these, remember right-hand rule, mv^2/R = qvBsin(theta), and circular motion of the charged particles.
Feel free to watch any parts of Magnetic Storm again or if you were not in class (NOVA video on Earth's magnetic field we saw in class; have those questions in our packet, page 2).
Period 5:
We are starting electricity, and the starting point is electric charge. EVERYTHING in electricity, and magnetism for that matter, starts with electric charge. You are probably most familiar with this from chemistry, in the form of protons and electrons, the positive and negative charges that make up every atom in your body!
Static electricity means stationary charge - charges that just sit on objects. Check out this video on the science of static charge. Take notes and answer the questions on this and the following two videos.
Static charge can build up in clouds, too! Check out a video on how lightning works: take notes and answer the questions you got in class on Wednesday. Here is a short, second video that compliments the first one.
Thanks, and enjoy the weekend!!!
For Attendance:
I got this yesterday, so I was unable to share with you in class. But there is a Google Form at https://docs.google.com/
The assignment, though, can be done at your convenience any time through the weekend!
Period 3-4, 8-9:
For magnetic forces, F = qv x B, try two ActivPhysics simulations. These are set up as lessons, so just follow along and type up your responses in a Google Doc that is shared with Doc V at vondracekm@eths202.org.
- Go to Part VI on the home page, which is Electricity & Magnetism. Try 13.4, Magnetic Force on a Particle. You may have to click to enable Adobe Flash Player, but this was working on my Chromebook. Click on the box on the right side to open the simulation, and follow the various questions that will require you to run the simulation. Respond to questions, and write out all responses, explanations, and descriptions that are asked for.
- Then try 13.7, Mass Spectrometer. Same deal, use the simulation of a mass spectrometer to determine isotopes of different elements. Type up responses in your Google Doc, and share both when finished.
For each of these, remember right-hand rule, mv^2/R = qvBsin(theta), and circular motion of the charged particles.
Feel free to watch any parts of Magnetic Storm again or if you were not in class (NOVA video on Earth's magnetic field we saw in class; have those questions in our packet, page 2).
Period 5:
We are starting electricity, and the starting point is electric charge. EVERYTHING in electricity, and magnetism for that matter, starts with electric charge. You are probably most familiar with this from chemistry, in the form of protons and electrons, the positive and negative charges that make up every atom in your body!
Static electricity means stationary charge - charges that just sit on objects. Check out this video on the science of static charge. Take notes and answer the questions on this and the following two videos.
Static charge can build up in clouds, too! Check out a video on how lightning works: take notes and answer the questions you got in class on Wednesday. Here is a short, second video that compliments the first one.
Thanks, and enjoy the weekend!!!
Tuesday, February 5, 2019
Top 10 Future Energy Sources
Check out this video on one group's choices for the Top 10 future energy sources we humans should be using in the near future! Which one do you find most intriguing/interesting/promising? Do you see any potential problems for any of these?
Sunday, February 3, 2019
Making a 'Breaking News' screenshot
Need a cover page for a report? Or want a creative way to make a series of Breaking News headlines that can be ordered to show the chronology of an event or period of time? Try this breaking news screenshot generator, looks pretty cool!
Friday, February 1, 2019
February 1, 2019
Happy Friday! Some of us are at a contest today, so check out the following:
Period 3-4, 8-9
Be sure to have what you need for the magnet lab, with the exception of #6. If you have not yet done so, turn in the lab. Also turn in the magnetic domain and earth magnetic field sheets in the pack from early this week.
Check out two videos. One is on the earth's magnetic field. The second is on charged particles moving through magnetic fields. The symbol for a magnetic field strength is B, and the unit for magnetic field strength is a Tesla (1 Tesla is a really strong field...our big magnet is a fraction of a Tesla). Take notes on all this. You will start to use cross products as well as right-hand rules to figure out the direction particles get pushed by magnetic forces. Circular motion results from these cross product forces, so work together to try and figure out a few things.
Be sure to get a page with some practice problems from the book. It uses this notion of circular motion of particles in a magnetic field (or B-field). We are using mv^2/R = qvBsin(theta). In many cases the angle between velocity and the B-field will be 90-degrees, so the sine will often be 1.
/
Period 5
If your coaster group has not yet shared the summary paper for your coaster, please do so today. We are into energy, and the BIG idea we've been introducing is conservation of energy - perhaps the single most important concept in science, and a reason why we are alive. Energy can transform from one type into another, such as potential energy (due to height) converting back and forth into kinetic energy as something moves up and down hills on a roller coaster, or flies through the air (slows as it rises, with KE => PE; or speeds up as it falls, with PE => KE).
To see examples of the math behind conservation, check out this Khan Academy video on conservation of energy. This one shows basic PE-KE conversions, similar to what you had with your coaster. Remember conservation means "energy can be neither created nor destroyed, just transformed from one type to another" if there is nothing else adding or taking energy away from you (such as someone pushing or pulling an object, and forcing it to speed up or slow down). Do take notes on the video so you have a numerical example of how to deal with conservation.
From the video, then try to complete the conservation of energy sheet you got on Tuesday. Just remember in all the examples shown, the TOTAL energy stays the same, where Total E = PE + KE. Work together and talk things through based on the video example. If you complete it, turn it in before leaving and we will pick this up next week! Thanks!
Period 3-4, 8-9
Be sure to have what you need for the magnet lab, with the exception of #6. If you have not yet done so, turn in the lab. Also turn in the magnetic domain and earth magnetic field sheets in the pack from early this week.
Check out two videos. One is on the earth's magnetic field. The second is on charged particles moving through magnetic fields. The symbol for a magnetic field strength is B, and the unit for magnetic field strength is a Tesla (1 Tesla is a really strong field...our big magnet is a fraction of a Tesla). Take notes on all this. You will start to use cross products as well as right-hand rules to figure out the direction particles get pushed by magnetic forces. Circular motion results from these cross product forces, so work together to try and figure out a few things.
Be sure to get a page with some practice problems from the book. It uses this notion of circular motion of particles in a magnetic field (or B-field). We are using mv^2/R = qvBsin(theta). In many cases the angle between velocity and the B-field will be 90-degrees, so the sine will often be 1.
/
Period 5
If your coaster group has not yet shared the summary paper for your coaster, please do so today. We are into energy, and the BIG idea we've been introducing is conservation of energy - perhaps the single most important concept in science, and a reason why we are alive. Energy can transform from one type into another, such as potential energy (due to height) converting back and forth into kinetic energy as something moves up and down hills on a roller coaster, or flies through the air (slows as it rises, with KE => PE; or speeds up as it falls, with PE => KE).
To see examples of the math behind conservation, check out this Khan Academy video on conservation of energy. This one shows basic PE-KE conversions, similar to what you had with your coaster. Remember conservation means "energy can be neither created nor destroyed, just transformed from one type to another" if there is nothing else adding or taking energy away from you (such as someone pushing or pulling an object, and forcing it to speed up or slow down). Do take notes on the video so you have a numerical example of how to deal with conservation.
From the video, then try to complete the conservation of energy sheet you got on Tuesday. Just remember in all the examples shown, the TOTAL energy stays the same, where Total E = PE + KE. Work together and talk things through based on the video example. If you complete it, turn it in before leaving and we will pick this up next week! Thanks!
Subscribe to:
Posts (Atom)