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Black Hole Orbits

Adapted from an Adler Planetarium Activity
  • Full Activity (pdf)
  • Suggested Talking Points (pdf)

    • Summary:

    Students are introduced to the basic properties and behavior of black holes through a brief discussion, including how it might be possible to detect black holes through their interaction with other stars. Then they "act out" binary star systems in pairs, walking slowly around one another in a darkened room with each pair holding loops of wire to simulate the gravitational interaction. Most of the students are wearing glow-in-the-dark headbands to simulate stars. Some are not wearing headbands and represent black holes. A small set of the black holes have flashlights to simulate X-ray emission.

    Purpose:

    To teach some of the properties of black holes and how they interact with normal stars.

    Audience:

    ~ 20 students (grade range 6th-9th) in a group works well

    Objectives:

    1. Explain the basic properties of black holes including

  • Escape velocity
  • Gravitational interactions
  • Accretion disks

  • Demystify black holes
  • Brainstorm with students ways they might observe objects or phenomena which they cannot see directly
  • Introduce basic X-ray physics

    • Materials:

    • 1 tennis ball
    • 5-6 loops of heavy gauge wire, ~ 36 inches in circumference
    • 5-6 loops of heavy gauge wire, ~ 60 inches in circumference
    • paper headbands (1 per student)
    • glow-in-the-dark stickers and/or decorations
    • tape or stapler
    • 6 flashlights and batteries
    • red cellophane to cover flashlight lenses
    • tissue paper party decorations - 2 large (~ 8 inch diameter) balls, 1 large (~ 24 inch diameter) disk
    • room with adequate space to move around for the activity
    • completely blacked-out room (optional)
    Materials for the black hole activity

    Kit and Room Preparation:

    1. Wire loops: ~ 10 minutes

      Cut and shape the wire into 5-6 medium sized loops (~ 36 inches in circumference) and 5-6 large loops (~ 60 inches in circumference)

    2. Decorate the headbands (this can be done in advance or with the students): ~ 10 minutes
    3. Darken the room: ~ 10 minutes

      The room should be capable of going from brightly lit to dark so that the glow-in-the-dark headbands can be seen effectively. Sometimes this means lights or light leaks must be covered. Dark black plastic trash bags and duct tape have proved useful for this.