Circle Trigonometry

  • trigonometry cosine sine math circle
    • assignment Paramagnet (multiple solutions)

      assignment Homework

      Paramagnet (multiple solutions)
      Energy and Entropy 2021 (2 years) We have the following equations of state for the total magnetization \(M\), and the entropy \(S\) of a paramagnetic system: \begin{align} M&=N\mu\, \frac{e^{\frac{\mu B}{k_B T}} - e^{-\frac{\mu B}{k_B T}}} {e^{\frac{\mu B}{k_B T}} + e^{-\frac{\mu B}{k_B T}}}\\ S&=Nk_B\left\{\ln 2 + \ln \left(e^{\frac{\mu B}{k_B T}}+e^{-\frac{\mu B}{k_B T}}\right) +\frac{\mu B}{k_B T} \frac{e^{\frac{\mu B}{k_B T}} - e^{-\frac{\mu B}{k_B T}}} {e^{\frac{\mu B}{k_B T}} + e^{-\frac{\mu B}{k_B T}}} \right\} \end{align}
      1. List variables in their proper positions in the middle columns of the charts below.

      2. Solve for the magnetic susceptibility, which is defined as: \[\chi_B=\left(\frac{\partial M}{\partial B}\right)_T \]

      3. Using both the differentials (zapping with d) and chain rule diagram methods, find a chain rule for:

        \[\left(\frac{\partial M}{\partial B}\right)_S \]

      4. Evaluate your chain rule. Sense-making: Why does this come out to zero?

    • group Paramagnet (multiple solutions)

      group Small Group Activity

      30 min.

      Paramagnet (multiple solutions)
      • Students evaluate two given partial derivatives from a system of equations.
      • Students learn/review generalized Leibniz notation.
      • Students may find it helpful to use a chain rule diagram.
    • assignment Visualization of Wave Functions on a Ring

      assignment Homework

      Visualization of Wave Functions on a Ring
      Central Forces 2023 (3 years) Using either this Geogebra applet or this Mathematica notebook, explore the wave functions on a ring. (Note: The Geogebra applet may be a little easier to use and understand and is accessible if you don't have access to Mathematica, but it is more limited in the wave functions that you can represent. Also, the animation is pretty jumpy in some browsers, especially Firefox. Imagine that the motion is smooth.)
      1. Look at graphs of the following states \begin{align} \Phi_1(\phi)&=\frac{1}{\sqrt{2}}(\left|{2}\right\rangle +\left|{-2}\right\rangle )\\ \Phi_2(\phi)&=\frac{1}{\sqrt{2}}(\left|{2}\right\rangle -\left|{-2}\right\rangle )\\ \Phi_3(\phi)&=\frac{1}{\sqrt{2}}(\left|{2}\right\rangle +i\left|{-2}\right\rangle ) \end{align} Write a short description of how these states differ from each other.
      2. Find a state for which the probability density does not depend on time. Write the state in both ket and wave function notation. These are called stationary states. Generalize your result to give a characterization of the set of all possible states that are stationary states.
      3. Find a state that is right-moving. Write the state in both ket and wave function notation. Generalize your result to give a characterization of the set of all possible states that are right-moving.
      4. Find a state that is a standing wave. Write the state in both ket and wave function notation. Generalize your result to give a characterization of the set of all possible states that are standing waves.
    • groups Pineapples and Pumpkins

      groups Whole Class Activity

      10 min.

      Pineapples and Pumpkins
      Static Fields 2022 (6 years)

      Integration Sequence

      There are two versions of this activity:

      As a whole class activity, the instructor cuts a pumpkin in order to produce a small volume element \(d\tau\), interspersing their work with a sequence of small whiteboard questions. This version of the activity is described here.

      As a small group activity, students are given pineapple rounds and pumpkin wedges to explore area volume elements in cylindrical and spherical coordinate systems. In this version of the activity, the fruit is distribued to the students with appropriate children's pumpkin cutting equipment, as part of activities Vector Differential--Curvilinear, Scalar Surface and Volume Elements, or Vector Surface and Volume Elements.

    • group Equipotential Surfaces

      group Small Group Activity

      120 min.

      Equipotential Surfaces

      E&M Quadrupole Scalar Fields

      Students are prompted to consider the scalar superposition of the electric potential due to multiple point charges. First a single point charge is discussed, then four positive charges, then an electric quadrupole. Students draw the equipotential curves in the plane of the charges, while also considering the 3D nature of equipotentials.
    • group The Hill

      group Small Group Activity

      30 min.

      The Hill
      Vector Calculus II 2022 (4 years)

      Gradient

      Gradient Sequence

      In this small group activity, students determine various aspects of local points on an elliptic hill which is a function of two variables. The gradient is emphasized as a local quantity which points in the direction of greatest change at a point in the scalar field.
    • group Visualizing Plane Waves

      group Small Group Activity

      60 min.

      Visualizing Plane Waves

      Each small group of 3-4 students is given a white board or piece of paper with a square grid of points on it.

      Each group is given a different two-dimensional vector \(\vec{k}\) and is asked to calculate the value of \(\vec{k} \cdot \vec {r}\) for each point on the grid and to draw the set of points with constant value of \(\vec{k} \cdot \vec{r}\) using rainbow colors to indicate increasing value.

    • computer Visualizing Combinations of Spherical Harmonics

      computer Mathematica Activity

      30 min.

      Visualizing Combinations of Spherical Harmonics
      Central Forces 2023 (3 years) Students observe three different plots of linear combinations of spherical combinations with probability density represented by color on the sphere, distance from the origin (polar plot), and distance from the surface of the sphere.
    • group The Hillside

      group Small Group Activity

      30 min.

      The Hillside
      Vector Calculus I 2022

      Gradient Sequence

      Students work in groups to measure the steepest slope and direction on a plastic surface, and to compare their result with the gradient vector, obtained by measuring its components (the slopes in the coordinate directions).
    • assignment Light bulb in a refrigerator

      assignment Homework

      Light bulb in a refrigerator
      Carnot refridgerator Work Entropy Thermal and Statistical Physics 2020 A 100W light bulb is left burning inside a Carnot refridgerator that draws 100W. Can the refridgerator cool below room temperature?
  • Quantum Fundamentals 2022 (2 years)

    On the following diagrams, mark both \(\theta\) and \(\sin\theta\) for \(\theta_1=\frac{5\pi}{6}\) and \(\theta_2=\frac{7\pi}{6}\). Write one to three sentences about how these two representations are related to each other. (For example, see: this PHET)

  • Media & Figures
    • figures/sinewave.png
    • figures/unitcircle.png
    • figures/circletrigsol2.png
    • figures/circletrigsol1.png