Science
Objectives
  • Know what a reflex action is and compare it to a voluntary action.
  • Explain the reflex arc.
End Product

  • Produce a document which explains reflex and voluntary actions. Include a diagram of the reflex arc. Reflex arc picture p15

Reflex and Voluntary Actions - Task 17
  • Volunteer a member of the class to demonstrate to the group the knee jerk reflex, your teacher will explain this to you although you have probably seen it on the TV.
  • Once you have seen how it is done, practice with a partner and see how your reflexes compare.
  • Work in pairs to observe the alteration in pupils size when the eyes are opened in bright and dim light. How does this reflex protect the eyes? Put your findings and the answer to this question into a document called ‘Reflex Actions’.
  • Into this document you now need to add some notes on the reflex arc, research what it is and then draw it out (include labels!) Good Reflexes
  • Now for a quick practical. In pairs, one of you needs to hold a metre ruler vertically at the zero end, between the thumb and forefinger of your partner. Without warning, the drop the ruler and your partner needs to attempt to catch it. Record the measurement and repeat so that a mean can be calculated.
  • What do tests such as the stick drop test tell us? Identify the parts of the body involved. What senses are being used? Can we train ourselves to react more quickly? Have a think about this and then add your ideas to your work.