Don't dis me! - orient - motion sickness

Science World, Jan 15, 1993

Many scientists think astronauts get motion-sick because of conflicting signals from their senses. Their eyes might tell them that down is where their feet are. But their inner ears, which are totally dependent on gravity to give a sense of balance, don't know which end is up.

You can investigate the effect of vision on disorientation by spinning some friends with their eyes open and closed. To measure how disoriented each subject gets, test them on a variety of tasks before and after spinning. The more disoriented they get, the worse they should perform.

WHAT YOU NEED:

* 2 swivel chairs * 2 volunteers to spin in chairs (WARNING: This activity will cause dizziness)

* 2 people to spin chairs * 2 pencils * blindfold * stopwatch * 2 copies of 2 mazes of equal difficulty

WHAT TO DO:

A. Pre-spin test

Give spin volunteers one maze and one pencil each. Time and record how long it takes each to complete the maze.

B. Spin

1. Ask volunteers to sit in swivel chairs, holding pencils points-up with arms stretched in front of them, feet off the floor.

2. Blindfold one subject. Tell the other to keep his or her eyes open. Tell both that once the spinning starts, they should always point their pencils in the direction of rotation.

3. Have pushers spin each subject at the same speed (not too fast) and in the same direction. In the Data Table, note whether the subjects point their pencils accurately.

[TABULAR DATA OMITTED]

4. After four or five rotations, have the pushers slow trhe subjects gradually to a monentary stop, and then spin them again in the opposite direction. Note the direction of the pencils and what the subjects say about how they feel.

C. Post-spin test

1. After four or five rotations in the new direction, stop the spinners and give them the second set of mazes. (Have the blindfolded subject take the blindfold off.) Again time subjects to see how long they take to complete the maze. Record in Data Table.

2. Calculate the difference between pre- and post-spin maze completion times for each subject. Did the subjects do worse after spinning? Was one subject more disoriented than the other? Try to come up with an explanation for any effects you found.

DON'T STOP NOW!

You could test the subjects on other skills both before and after spinning. Try giving them math problems, strength tests, exercises, what else?

How might astronauts be affected by having these skills impaired? Based on your results, can you suggest anything to help astronauts keep from feeling sick?

Find out how dancers, ice skaters, and others who spin keep from getting sick. Redesign this experiment to test their techniques.