Drawing conclusions from experimental observations
Modifying theories and models based on scientific conclusions
After an initial observations, the students believe they know how the strings are connected inside the Mystery Tube. After you perform a second "experiment", their observations confuse them. They have to revise their model. Finally, your third "experiment" baffles them. Just how are the strings connected?
After performing this demonstration, students BEG me to tell them the secret for months... a few will try for more than a year. Some have tried to steal the Mystery Tube... one actually succeeded. Some have built their own at home just so they can figure out how it works.
This is a fun demonstration and students will learn a lot about scientific investigation.
Video clip for further information: (5 minutes long)