suggestions or tips on a successful LED circuit

[dougy]

I received materials yesterday in the mail for activity 4 "what can destroy a metal", and I hooked up a circuit following the directions given in the text.  I cannot get the circuit to work as described.     Does anyone have a trick or suggestion that could be helpful?  Thanks! 

[pretzej]

This might be a little late, but here is what I've written up for students.  I projected diagrams of a circuit and short circuit from the internet. 

The students do experiment with a set up, but finally most discover they need to suspend the short circuit (Al, Zn, or Mg) over a petri dish and drip the solution on it.  If it lays in the ionic solution, it'll still be shorted b/c the solution conducts...leads to nice discussions afterwards (with the 4 essential questions).

Best,
Josh

Preparing
Your instructor will demonstrate how to diagram a circuit (Figures 5.3).  In this lab you will work with a short circuit (for some reason “Number Five” keeps running through my head…anyone know why?).  A short circuit (Figure 5.4) will divert the flow of electrons from the resistor (or light bulb), leaving the LED off.  Remembering the goal is to light the LED:
1.   How could you use what you learned in Forensics to destroy a short circuit if the short metal circuit didn’t have a plastic coating?
2.   What type of metal would you use?  Why?
State your learning objectives for this lab in the form of a question or two (an essential question or two).  What questions should you be able to answer once you’ve completed this lab?  Share your objective (essential) question(s) with your group before heading back to the lab.
Note: There are a variety of announcements for this activity dealing with safety – understand how to be safe your laboratory materials!

Short Circuit - Experimenting
You have three different materials to make the circuit out of magnesium, aluminum, and zinc.  You will need to:
1.   Create a circuit to light the light out of any of the three metals.  Have this checked by your instructor.
2.   Create a short in the circuit (short circuit) using one of the three metals and have it checked by your instructor.  Be prepared to discuss how you could destroy this short using what you’ve learned in Forensics by showing your instructor a macro / nano / symbolic chart filled out in your notebook or on a white paper or board provided.
3.   Test various ways to destroy shorts made of magnesium, aluminum, and zinc.  In your laboratory notebook keep track of your observations, so that if you choose to use this in your project, you will have data on various options for your set up.

[dougy]

Thanks for your comments--they are very helpful, especially the part about the solution itself keeping the circuit intact.  We got better results when we used aluminum foil instead of magnesium as the metal sample.