Student Guide

Mystery Tube

What is a scientific model and how do we create one?

This resource was originally published in PhysicsQuest 2021: Introduction to the World of Quantum.

What is a scientific model and how do we create one?

  • One drinking straw: cut up to tie to the ends of the string for the mystery tube to use as washer
  • One tube: 1.5 in. x 9 in. x 0.04 in.
  • One push pin: to pierce the side of the tube before the skewer is used to create the hole
  • One skewer: 4.5 in. x 11/64 in. to create the appropriate size hole in the tube
  • One thin pull wire to make threading the string through the holes easier
  • Yoyo string
  • Paper/whiteboard + pen/marker to write your observations
Intro

Have you ever wondered how scientists figure out how things work when they do not have a direct way of measuring the phenomena? For example, how do we know that the structure of an atom consists of electrons revolving around a positively charged nucleus, like the planets around the sun? In this activity, we will learn how to build scientific models based on observations, realize that different models can explain the same observations, and refine our models based on new data.

After reading the introduction, what is your essential question or objective for this activity?


Before the experiment
  • Turn & talk protocol

    Give students examples of pictures, diagrams, 3D models to look at. Ask them to describe the purpose of a model in science.

Setting up

  • Obtain a mystery tube from your teacher. Work with your group to predict what is going on inside. Create an initial model by following the instructions below.

During the experiment

  • Provide a mystery tube per group (groups of 5 max). Tell students that they need to draw a design of how the tube works without opening the tube. Ask students to follow the scientific method, to formulate hypotheses/predictions of what will happen when they pull the different string ends. Does it make a sound when you shake it? Does the diameter of the tube, strings, rings matter, or the length?

  • Allow students enough time to try their combinations, noting the motion and tension of the strings or anything else that might help them decipher how the tube looks inside.

  • Once the students in the group have reached a conclusion, ask them to draw their designs and share them with the class. Provide some time for a peer-review process in which students get to ask questions about their peers’ designs. Ask the groups if they want to revise their model after the peer-review session is completed.

  • Once students have revised their models and adjusted their designs, provide the materials they request and ask them to build their own model.

  • With the class, define a way to systematically test the accuracy of each group’s model – maybe by analyzing the diagram to see if it could predict the behavior that is actually witnessed when the strings are pulled, how the physical model compares to the diagram, and if it actually behaves as it was expected.

Conclusion

  • Once all the models are built, use the accuracy test to judge the models. The models must be judged primarily on their ability to explain and predict the observations.

  • Discuss how different models can arrive at the same observations and reflect what areas of science use models in similar ways – such as the model of the atom or the electron (particle and wave).

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