SCH SCIENCE DEPARTMENT @ PHILADELPHIA SCIENCE FESTIVAL 2013
Reflexes and Balance
Reflexes are involuntary, rapid responses to the internal or external environment that allow
the body to maintain homeostasis. A reflex action happens automatically and in the same
way every time a particular kind of stimulus is detected by a particular set of sensory
receptors. Preventing a reflex response requires conscious inhibition of effector (muscle or
gland) activity. A good example is stopping yourself from blinking when you know someone
is going to move his or her hand toward your eyes.
Maintaining Your Posture: Static equilibrium - ask the subject to stand still with feet close
together and medial malleoli (bone sticking out on inner ankle) touching. Compare the
amount and kinds of body movement needed to maintain this position for 1 minute, first with
eyes open and then with eyes closed.
Testing Touch
1. Determining the Two-Point Threshold
2. Testing tactile Localization
3. Demonstrating Adaptation of Touch Receptors
Heart Rate and Relaxation Techniques:
Most of the actions of this part of your nervous system are involuntary reflexes, geared
toward maintaining homeostasis under the varying conditions that the body encounters.
Many people try to learn to control some aspect of their autonomic nervous system, using
relaxation techniques, biofeedback, or meditation. They often hope to reduce stress, lower
blood pressure, or ease chronic pain.
1. Heart rate is an easy parameter of body function to measure and is under autonomic
control. Find your pulse in the radial artery just below your wrist on your thumb side
(lateral). Count the number of beats in 15 seconds. Multiply by 4. That number is the
number of beats per minute of your heart - your heart rate.
Pulse = _____________
2. Follow the breathing exercises described by your teacher and/or smell the scents.
Take your pulse at the end of the exercises.
Pulse = ___________
Vision:
Eye Dominance:
Place a coin on the floor. Carefully roll this paper into a tube and look through the tube with
both eyes in order to observe the penny. Now close one eye at a time while still looking
through the tube. With which eye could you see the penny?
This is your
dominant eye!
Near Point of Accomodation:
Close your right eye. Hold your pen at arm’s length and slowly move it inward toward your
nose. (notice what happens to your partner’s eyes when she does this). Measure the distance
at which you can no longer see the pen tip clearly.
Color Vision
1. Ichihara Color Plates
Were you able to see all of the numbers?
problematic?
If not, which colors were
2. Holmgren Test – Match the colored swatches of yarn as quickly as possible. Time how
long it takes to do so.
___________ sec.
__________ # wrong matches
Visual Memory:
http://people.brandeis.edu/~sekuler/MemoryDemo/FaceDemo/facedemogrid.html
Optical Illusions:
T-Illusion
http://www.michaelbach.de/ot/sze_t-illusion/
http://www.michaelbach.de/ot/mot-feet_lin/index.html
http://www.michaelbach.de/ot/mot_adapt/index.html
http://www.michaelbach.de/ot/ang-cafewall/index.html
http://www.michaelbach.de/ot/ang_tiltedTable/index.html
http://www.michaelbach.de/ot/fcs_hollow-face/index.html
http://www.michaelbach.de/ot/mot-silencing/index.html