Name: ________________________ Period: ____ Date: ____________

 

Activity 1: Student Worksheet

A. Making a Model of an Active Galaxy

The styrofoam ball represents the black hole at the center of the active galaxy. In the next few steps, you are going to make an accretion disk, cones that represent the jets of the active galaxy, and the torus that surrounds the accretion disk.

question symbol

supplies
1. What you need
circle
2. Cut out annular disk inner circle
circle and ball
3. Assemble annular disk and styrofoam ball
circle
4. 20 cm circle

 

1. Accretion Disk: Measure the diameter of your ball, just to be sure of the size. Note the size both in inches and centimeters here (1 in = 2.54 cm)

question 1
With your compass, draw a circle with the diameter of your styrofoam ball on the heavier weight construction paper. Using the same center, draw a concentric circle with twice the diameter. Cut the large circle and then cut out the inner circle to make an annular disk (a ring with a hole in the center). Gently work the styrofoam ball through the inner circle of your annular disk until it is exactly in the middle. This is your accretion disk! You can draw a swirling vortex on it and label “accretion disk” or other appropriate descriptive words that describe the properties of the disk.


2. Jets: With your compass, draw a circle 20 cm in diameter on the lightweight construction paper. With your ruler, draw 2 perpendicular lines through the center as shown. Cut the circle out and cut it in half. Each semicircle will be rolled into a cone to make a jet. Hold the half circle so that the drawn line is on the inside of the cone. Curl up the inner edge of the paper to the drawn line to make your cone. Tape the outside edge.

Make sure the apex of your cone is nice and tight so you can stick it to the styrofoam ball with a toothpick. When you have made both jets, attach them to the styrofoam ball by piercing the apex with a toothpick and sticking the cones symmetrically on the ball above and below the accretion disk.

folding circle
5. Cut the circle in half
folding cone
6. Roll it into a cone
cone

7. Tape the edge to form a cone
assembled
8. Attach the cones to the styrofoam ball


question 2

question 3,4

3. Torus:
Using your ruler, mark the dimensions of your torus strip on the lightweight construction paper and cut it out. Color and label the strip with descriptive terms and then wrap it around the accretion disk so that it has equal height above and below the plane of the disk. When viewed edge on, the torus should obscure the accretion disk and the black hole. Attach it to the accretion disk with tape.
active galaxy


B. Drawing the Active Galaxy Model from Different Perspectives

View your active galaxy model from the following three views:

1. Down a jet
2. At an angle to the jet (not 90 degrees!)
3. 90 degrees from the jet


question 5

Attach your drawings to this worksheet before you hand in your work.