A hidden switch is one that you operate without seeing it. In this lesson, students discuss the results of the Hidden Switch Hunt done as homework (see Lesson 5), and brainstorm additional examples. Then they make hidden switches, and incorporate them in their own gadgets
The Hidden Switch Hunt: Chart examples of hidden switches that students have found as homework. For each one, list where it is found, what it controls and what you have to do to operate it. For example, a refrigerator has a switch that turns on the light when you open or close the door. See Troubleshooting for more examples.
Design a gadget: Show students two assembled cardboard boxes – one of each size – and a clothespin. They can use these or cardstock to make gadgets that are controlled by hidden switches. What would they like to make? Conduct a brainstorming session to develop and chart a list of possible ideas. See Troubleshooting for some suggestions.
How to make a hidden switch: How will they make the hidden switch that will be inside the gadget? Ask students for ideas, and if necessary demonstrate the five sample hidden switches.
Make your gadget:
Provide time for students to make their gadgets. If students become frustrated, remind them of the discussion about troubleshooting in the previous lesson.
Hidden Switch Hunt: Here are some examples that students may not have listed:
Ideas for gadgets: Here is a list of gadgets students have thought of; click on the blue links to see videos of the first five items:
* A dollar-bill theft alarm that uses a clothespin switch to protect a dollar bill from being stolen; the same idea can be used to make a cabinet alarm, by tying a piece of cardboard to the door and inserting it in the clothespin
* A light-up card whose LED turns on when the book is closed
* An alarm clock that buzzes when pressed from behind; the same idea can be used to make a squeeze-me toy
* A wind alarm that buzzes when it is breezy
* A color wheel that spins when a box is opened
* A light box, close the box and see the light through the peep hole;
* A buzz box, which buzzes when closed
* An airplane or helicopter: the propeller starts turning when the box is closed
* A seat-controlled car horn, which sounds when you lean back on the seat
* An upside-down alarm, which goes off when the box is turned upside-down