Dan Hosey
@danhosey.bsky.social
HS Physics Teacher. Desmos simulation fan. Spreadsheets too. Always tinkering.
www.mrhosey.com/desmos
www.mrhosey.com/desmos
Playing with iterating through preset parameters for a @desmos simulation. A table of values makes it easy to cycle through different scenarios. This particular sim is for equilibrium of a rod supported by a cable. www.desmos.com/calculator/b...
October 23, 2025 at 2:10 PM
Playing with iterating through preset parameters for a @desmos simulation. A table of values makes it easy to cycle through different scenarios. This particular sim is for equilibrium of a rod supported by a cable. www.desmos.com/calculator/b...
Speaking of, I just put this together this week to teach vector addition.
www.desmos.com/geometry/ont...
www.desmos.com/geometry/ont...
October 9, 2025 at 12:07 AM
Speaking of, I just put this together this week to teach vector addition.
www.desmos.com/geometry/ont...
www.desmos.com/geometry/ont...
Time is neither color. It doesn't belong to X or Y. It is ususually the one thing that links them. Here are some early notes. It leads to somewhat less mistakes, but gives us a languate to talk about the kind of conceptual mixup. "Oh, I made purple". [4/n]
October 6, 2025 at 3:00 PM
Time is neither color. It doesn't belong to X or Y. It is ususually the one thing that links them. Here are some early notes. It leads to somewhat less mistakes, but gives us a languate to talk about the kind of conceptual mixup. "Oh, I made purple". [4/n]
Upside: Path of totality went through my driveway. Downside: It was completely cloudy. Upside: Still got great brightness data, and learned a lot about the logness of our perception of brightness and made a simulation to demonstrate. #iTeachPhysics www.desmos.com/calculator/8...
April 8, 2025 at 7:46 PM
Upside: Path of totality went through my driveway. Downside: It was completely cloudy. Upside: Still got great brightness data, and learned a lot about the logness of our perception of brightness and made a simulation to demonstrate. #iTeachPhysics www.desmos.com/calculator/8...
#iTeachphysics Noticed 2 sets of reflection in my reading glasses of the 4 candelabra lights above my kitchen table. One set is of the 4 white bulbs I expect. The other reflection makes the bulbs blue. Another pair of glasses makes the 2nd reflection green. Any thoughts on what is going on?
March 16, 2025 at 12:57 AM
#iTeachphysics Noticed 2 sets of reflection in my reading glasses of the 4 candelabra lights above my kitchen table. One set is of the 4 white bulbs I expect. The other reflection makes the bulbs blue. Another pair of glasses makes the 2nd reflection green. Any thoughts on what is going on?
If you "throw" the light side down, so it goes down, stops, then goes up. Do you get a different acceleration each way? As friction changes direction.
March 13, 2025 at 2:16 AM
If you "throw" the light side down, so it goes down, stops, then goes up. Do you get a different acceleration each way? As friction changes direction.
Very Cool. If you had a big enough capacitor and resistor combo with a pleasant RC time constant, I've always thought this would be fun to see. I've set it up with meters, but never with light bulbs and certainly not an IR Camera. Would be fun to see one resistor dim while the other brightens.
March 11, 2025 at 11:47 PM
Very Cool. If you had a big enough capacitor and resistor combo with a pleasant RC time constant, I've always thought this would be fun to see. I've set it up with meters, but never with light bulbs and certainly not an IR Camera. Would be fun to see one resistor dim while the other brightens.
#ITeachPhysics Thank you to @sstoneb.bsky.social for time and thoughtful feedback. I am much happier with this "Capacitor Intuition" @desmos.com simulation now. www.desmos.com/calculator/c...
February 24, 2025 at 2:01 PM
#ITeachPhysics Thank you to @sstoneb.bsky.social for time and thoughtful feedback. I am much happier with this "Capacitor Intuition" @desmos.com simulation now. www.desmos.com/calculator/c...
#ITeachPhysics I've been working on an electrostatics @desmos.com simulation to build up student intuition for parallel plate capacitors including a partial dielectric. I am a little too close to it right now, does this simulation make sense to others? www.desmos.com/calculator/o...
February 20, 2025 at 5:29 AM
#ITeachPhysics I've been working on an electrostatics @desmos.com simulation to build up student intuition for parallel plate capacitors including a partial dielectric. I am a little too close to it right now, does this simulation make sense to others? www.desmos.com/calculator/o...
The default example has an orbital period of about 54 seconds. Even with a time step size of 1 second, the orbit seems stable. This is a screenshot of the trail after 100 orbits. Each dot equal 10 seconds. The period is 54 seconds. I didn't study your f(X,t) function close enough for precise fb
February 19, 2025 at 3:11 AM
The default example has an orbital period of about 54 seconds. Even with a time step size of 1 second, the orbit seems stable. This is a screenshot of the trail after 100 orbits. Each dot equal 10 seconds. The period is 54 seconds. I didn't study your f(X,t) function close enough for precise fb
These 2 actions run each time step to update position and velocity.
February 18, 2025 at 6:27 PM
These 2 actions run each time step to update position and velocity.
Similarly, the Next Velocity value for each of the 3 particles is calculated. When the tiem takes a step, the position will be set to this value.
February 18, 2025 at 6:27 PM
Similarly, the Next Velocity value for each of the 3 particles is calculated. When the tiem takes a step, the position will be set to this value.
The next Position value for each of the 3 particles is calculated. When the time takes a step, the position will be set to this value. Remember, Capital Q is the (X,Y) position of the charge. Velocities and k values are also all stored as "points" representing the x and y components.
February 18, 2025 at 6:27 PM
The next Position value for each of the 3 particles is calculated. When the time takes a step, the position will be set to this value. Remember, Capital Q is the (X,Y) position of the charge. Velocities and k values are also all stored as "points" representing the x and y components.
k4 Step for Velocity
February 18, 2025 at 6:27 PM
k4 Step for Velocity
k4 Step for Position
February 18, 2025 at 6:27 PM
k4 Step for Position
K3 Step for Velocity
February 18, 2025 at 6:27 PM
K3 Step for Velocity
K3 Step for Position
February 18, 2025 at 6:27 PM
K3 Step for Position
K2 Step for Velocity
February 18, 2025 at 6:27 PM
K2 Step for Velocity
K2 Step for Position
February 18, 2025 at 6:27 PM
K2 Step for Position
This is the k1 step for velocity for particle 1, 2, and 3. Usually this will the time step multiplied by some acceleration function that depends on position (though it can depend on velocity, such as with drag). Capital Qs are (X,Y) positions. Lower case qs are charge values.
February 18, 2025 at 6:27 PM
This is the k1 step for velocity for particle 1, 2, and 3. Usually this will the time step multiplied by some acceleration function that depends on position (though it can depend on velocity, such as with drag). Capital Qs are (X,Y) positions. Lower case qs are charge values.
h is the time step. The first digit of the subcript refers to the particle number (1,2, or 3). The 2nd digit refers to the the RK step number (similar to lines 13 to 16 of your your simulation). The a subscript refers to position.
February 18, 2025 at 6:27 PM
h is the time step. The first digit of the subcript refers to the particle number (1,2, or 3). The 2nd digit refers to the the RK step number (similar to lines 13 to 16 of your your simulation). The a subscript refers to position.