Phil Keller
@pckeller.bsky.social
High school physics teacher, a little math too. And dogs.
“That’s seasonal” is apparently trader Joe fancy talk for “yeah we don’t have that”. Like calling it seasonal, giving false hope of eventual return will make things better. I see right through that…
June 28, 2025 at 12:56 AM
“That’s seasonal” is apparently trader Joe fancy talk for “yeah we don’t have that”. Like calling it seasonal, giving false hope of eventual return will make things better. I see right through that…
If you are new to using Desmos, I have some brief intro videos here:
www.youtube.com/@digitalsatg...
Silly to take the SAT without these skills…
www.youtube.com/@digitalsatg...
Silly to take the SAT without these skills…
June 27, 2025 at 3:26 PM
If you are new to using Desmos, I have some brief intro videos here:
www.youtube.com/@digitalsatg...
Silly to take the SAT without these skills…
www.youtube.com/@digitalsatg...
Silly to take the SAT without these skills…
In case any of you work with SAT students, here’s a quick heads up: starting with the August test, the calculators that “do algebra” are no longer permitted. (So desmos fluency is even more important!). #Iteachmath
June 26, 2025 at 2:04 PM
In case any of you work with SAT students, here’s a quick heads up: starting with the August test, the calculators that “do algebra” are no longer permitted. (So desmos fluency is even more important!). #Iteachmath
Not saying it’s the best way, but I just realized you can show that the derivative of x^p =px^(p-1) for all positive integers p using the product rule and then induction. Just saying…#iteachmath
June 20, 2025 at 3:19 PM
Not saying it’s the best way, but I just realized you can show that the derivative of x^p =px^(p-1) for all positive integers p using the product rule and then induction. Just saying…#iteachmath
Things we need, things we don’t
Make an observation about your pantry that also sounds like the title of a novel.
Three Kinds of Olive Oil
Three Kinds of Olive Oil
Make an observation about your pantry that also sounds like the title of a novel.
Rock Hard Sugar
Rock Hard Sugar
May 18, 2025 at 1:10 AM
Things we need, things we don’t
I think I have mastered the Dunning-krueger effect. AMA...
May 16, 2025 at 11:51 AM
I think I have mastered the Dunning-krueger effect. AMA...
Teaching beats, played two notes together, 440 hz and 350 hz, then paused to explain what a dial tone is. #IteachPhysics and times change.
May 8, 2025 at 6:42 PM
Teaching beats, played two notes together, 440 hz and 350 hz, then paused to explain what a dial tone is. #IteachPhysics and times change.
I was totally nerd-sniped by this: A sphere is released from rest at the top of a ramp w angle theta. What value of mu will minimize the total mechanical energy it has at the bottom? I may have an answer that is reasonable and concise, at the end of messy work. #Iteachphysics
May 4, 2025 at 4:56 PM
I was totally nerd-sniped by this: A sphere is released from rest at the top of a ramp w angle theta. What value of mu will minimize the total mechanical energy it has at the bottom? I may have an answer that is reasonable and concise, at the end of messy work. #Iteachphysics
March 17, 2025 at 3:59 PM
I was writing an SAT math problem and I goofed -- and created a more interesting (but still SAT level) question:
x - 3y = 4
y = ax + by
If the system above has no solutions when a = 5, find b.
#Iteachmath
x - 3y = 4
y = ax + by
If the system above has no solutions when a = 5, find b.
#Iteachmath
March 14, 2025 at 7:44 PM
I was writing an SAT math problem and I goofed -- and created a more interesting (but still SAT level) question:
x - 3y = 4
y = ax + by
If the system above has no solutions when a = 5, find b.
#Iteachmath
x - 3y = 4
y = ax + by
If the system above has no solutions when a = 5, find b.
#Iteachmath
Changing the order of integration in 3d can be hard to visualize...#desmos 3d to the rescue! www.desmos.com/3d/kdggenuks7
#Iteachmath
#Iteachmath
triple integrals in different orders
www.desmos.com
February 28, 2025 at 5:09 PM
Changing the order of integration in 3d can be hard to visualize...#desmos 3d to the rescue! www.desmos.com/3d/kdggenuks7
#Iteachmath
#Iteachmath
Just got this to work: modeling pumping up amplitude on a swing, using Interactive Physics. #iteachphysics
February 6, 2025 at 5:30 PM
Just got this to work: modeling pumping up amplitude on a swing, using Interactive Physics. #iteachphysics
Okay, this is nonsense but... you know how the distance from Earth to sun is one astronomical unit? So then, from the Earth to the moon, that would be...1 zappa, right?
January 27, 2025 at 6:37 PM
Okay, this is nonsense but... you know how the distance from Earth to sun is one astronomical unit? So then, from the Earth to the moon, that would be...1 zappa, right?
I have an @desmos.com question: in 2d, you can use use the shift key to zoom on one axis at a time (which is nice!) Is there an equivalent to that in Desmos 3d? And if not, could there be? Something like shift-scroll for the x axis,ctrl for the y axis and alt for the z axis? TIA #Iteachmath
January 27, 2025 at 2:01 PM
I have an @desmos.com question: in 2d, you can use use the shift key to zoom on one axis at a time (which is nice!) Is there an equivalent to that in Desmos 3d? And if not, could there be? Something like shift-scroll for the x axis,ctrl for the y axis and alt for the z axis? TIA #Iteachmath
It's extra satisfying to see that a simple solar system modeled in Interactive Physics will in fact demonstrate Kepler's 3rd Law. Not as pretty as some websites, but I think there is value in seeing this tumble out of the simulation engine, rather than programmed in... #Iteachphysics
January 24, 2025 at 3:03 PM
It's extra satisfying to see that a simple solar system modeled in Interactive Physics will in fact demonstrate Kepler's 3rd Law. Not as pretty as some websites, but I think there is value in seeing this tumble out of the simulation engine, rather than programmed in... #Iteachphysics
It's interesting to think about inflection points in terms of the rotation of the tangent line. You can identify those points without even seeing the graph itself! Just watch that tangent line switch back and forth from CW to CCW. #Iteachmath www.desmos.com/calculator/t...
January 21, 2025 at 2:08 PM
It's interesting to think about inflection points in terms of the rotation of the tangent line. You can identify those points without even seeing the graph itself! Just watch that tangent line switch back and forth from CW to CCW. #Iteachmath www.desmos.com/calculator/t...
Not sure what to make of this…
December 23, 2024 at 9:06 PM
Not sure what to make of this…
Last demo of the year came out nice. And my break starts in just a few hours. So this is a good morning so far. #Iteachphysics
December 20, 2024 at 1:56 PM
Last demo of the year came out nice. And my break starts in just a few hours. So this is a good morning so far. #Iteachphysics
Here is an intro to partial derivatives and directional derivatives, focusing on their geometric meaning.
www.desmos.com/3d/25qiw4vzhg
#Iteachmath (If I keep working on these things, the papers will grade themselves, right?)
www.desmos.com/3d/25qiw4vzhg
#Iteachmath (If I keep working on these things, the papers will grade themselves, right?)
December 18, 2024 at 4:26 PM
Here is an intro to partial derivatives and directional derivatives, focusing on their geometric meaning.
www.desmos.com/3d/25qiw4vzhg
#Iteachmath (If I keep working on these things, the papers will grade themselves, right?)
www.desmos.com/3d/25qiw4vzhg
#Iteachmath (If I keep working on these things, the papers will grade themselves, right?)
Since it is a physics engine, "Interactive Physics" can surprise you. Here is a car going around a track. On the second lap, it hits an oil spill and friction vanishes. When I ran this, I discovered that I only partially knew what to expect! #Iteachphysics
December 10, 2024 at 7:03 PM
Since it is a physics engine, "Interactive Physics" can surprise you. Here is a car going around a track. On the second lap, it hits an oil spill and friction vanishes. When I ran this, I discovered that I only partially knew what to expect! #Iteachphysics
Putting it out to the universe: someone should buy the rights to "Interactive Physics" and then distribute it for free to students and teachers. There is still nothing quite like it...and it is slowly disappearing 🙁
Here is a look at the bowling ball problem...#Iteachphysics
Here is a look at the bowling ball problem...#Iteachphysics
December 9, 2024 at 2:25 PM
Putting it out to the universe: someone should buy the rights to "Interactive Physics" and then distribute it for free to students and teachers. There is still nothing quite like it...and it is slowly disappearing 🙁
Here is a look at the bowling ball problem...#Iteachphysics
Here is a look at the bowling ball problem...#Iteachphysics
Another fun Desmos3D creation. This one shows a hyperbolic paraboloid. You can see the cross sections parallel to the coordinate planes and how they knit together to form the surface.
www.desmos.com/3d/9hnbnkqutq
#IteachMath
#ShouldBeGradingPapers
www.desmos.com/3d/9hnbnkqutq
#IteachMath
#ShouldBeGradingPapers
Hyperbolic Paraboloid with Cross Sections
www.desmos.com
December 5, 2024 at 2:21 PM
Another fun Desmos3D creation. This one shows a hyperbolic paraboloid. You can see the cross sections parallel to the coordinate planes and how they knit together to form the surface.
www.desmos.com/3d/9hnbnkqutq
#IteachMath
#ShouldBeGradingPapers
www.desmos.com/3d/9hnbnkqutq
#IteachMath
#ShouldBeGradingPapers
Football thought about tanking: the draft order should be based on where you were when n weeks were left, with n determined by the roll of a die AFTER the season! And ties broken by # of WINS in those last n games. This would keep competition honest but worst teams would still draft earliest.
November 25, 2024 at 2:07 PM
Football thought about tanking: the draft order should be based on where you were when n weeks were left, with n determined by the roll of a die AFTER the season! And ties broken by # of WINS in those last n games. This would keep competition honest but worst teams would still draft earliest.