Build Your Own Seismograph

This seismograph can be built will some simple materials. Dimensions are approximate — you might be able to vary them or even modify the design. This is a harder version for those of you who love to build and tinker with your hands.. This project is worth 25 POINTS EXTRA CREDIT TEST GRADE.

  • Wood base (10 in x 24 in x 0.5 inch)
  • Wood stand (2 in x 4 in x 12 in)
  • Two wood support blocks (2 in x 4 in x 8 in)
  • Wood beam (1 in x 1 in x 20 in)
  • Two wood dowels (diameter = 0.25 in, length = 10 in )
  • (1 dowel must slide through center of adding machine paper roll)
  • Brick or other compact heavy weight
  • Stong wire, or non-elastic thick rope or twine (7 feet)
  • Roll of adding machine paper (width >= 2 in)
  • Smooth-sided can with lid and base ( similar dimensions as paper roll)
  • Round-headed screw or bolt or nail (1 in long)
  • Pen
  • Various sizes of nails
  • Masking tape, strapping tape, or duct tape

Part A

Build the seismograph according to the diagram. Here are some important steps or modications you may need: a) If you have a drill, you can mount the two wood dowels in holes drilled through the two wood support blocks. If you do not have a drill, saw two slots into the upper edge of each wood support block and then drop the dowel into these slots.

b) The pen must write easily when pulled down onto the paper roll by the brick. Cap it when not in use. You may try substituting a soft lead pencil, a charcoal pencil, a crayon, etc.

c) Fasten the wood stand securely to the wood base by nailing upward from underneath the wood base. The wire (or cord) attached to the back and side of the wood stand will help to keep it stable.

d) Fasten the screw securely into one end of the wood beam . This screw will rest against the wood stand so that the wood beam hangs level over the base. To help the screw stay in place and not slip off of the wood stand , drill or carve out of the stand a small hole 1/4-inch deep and slightly larger in diameter than the screw head. The head of the screw can sit in this hole and press against the wood stand.

e) Both the adding machine paper roll and the smooth can should be able to rotate. The smooth can rotates when you crank the nail at one end of its wood dowel; the paper roll can turn either with its wood dowel or separately from the dowel. Tape down the end of the paper roll onto the can so that when you crank the can, the paper should wind up around the can and cause the paper roll to rotate as it feeds paper to the can.

f) If you want to be creative, see if you can devise a way to make the paper roll feed onto the smooth can automatically so that you do not have to crank the can by hand. You might try buying a miniature battery-operated motor that can turn the wood dowel of the can.

Part B

  1. Have someone gently, and with short, brisk irregular movements, shake your model gently for 10 second to model a weak earth quake and then for 10 seconds to model a strong earthquake.
  2. Observe the pen markings on the paper strip. Compare how the seismograph recorded the weak earthquake and the strong earthquake. Record your observations in the chart
  3. Repeat Steps 1–4 with a new paper strip. Compare the two paper strips to see how consistent your seismograph recordings were. Record your observations.
  4. As the shaking of the box increases, what happens to the lines on the paper? Try pounding on the table and see what kind of lines it makes. How sensitive is your seismometer? Does it record footsteps? Try making some changes to it so that it can detect really small movements in the air such as when you sing or talk softly.
  5. Mark a new strip of paper with lines 1” apart. Can you pull the paper through so that 1” of paper passes under the pen every 10 seconds? Practice this with several strips of paper.

Analyze and Conclude

  1. Evaluating What problems or shortcomings did you encounter with the seismograph you tested in Part 1? Why do you think these problems occurred?
  2. Designing A Solution How did you incorporate what you learned in Part 1 into your seismograph design in Part 2? For example, what changes did you make to improve consistency from trial to trial?
  3. Troubleshooting As you designed, built, and tested your seismograph, what problems did you encounter? How did you solve these problems?
  4. Working With Design Constraints What limitations did factors such as gravity, materials, costs, time, or other factors place on the design and function of your seismograph? Describe how you adapted your design to work within these limitations.
  5. Evaluating The Impact On Society Why is it important for scientists around the world to have access to accurate and durable seismographs?

CLOSURE ACTIVITY
Write an advertisement trying to “sell” your seismograph. In your ad, explain how your design and evaluation process helped you improve your seismograph. Include a labeled sketch of your design.