Magnetic Induction (Jake Dickerman "Impossible Drop")

Author

Jake Dickerman

Principle(s) Illustrated

• Copper is not a ferrous magnetic material. However, it has fantastic conductive properties. When a strong magnet moves quickly next to copper, the moving magnetic field induces an electrical current in the copper. The current creates a magnetic field which repels the magnet, slowing its drop within the copper pipe.

Standards

• Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims or determine an optimal design solution. (HS-PS2-1)

• Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanations of phenomena. (HS-PS2-4)

• Forces at a distance are explained by fields (gravitational, electric, and magnetic) permeating space that can transfer energy through space. Magnets or electric currents cause magnetic fields; electric charges or changing magnetic fields cause electric fields. (HS-PS2-4),(HS-PS2-5)

Questioning Script

Prior knowledge & experience:

Forces accelerate masses. Gravity pulls objects down, in order to slow an object an opposing force must act in the opposite direction of gravity.

Root question:

If we drop a magnet through these two pipes, which will get to the bottom first? (In the demo, suggest that you are initially testing Galileo's statement that all objects accelerate at the same rate.

Target response:

Both objects should hit the ground at the same time.

Common Misconceptions:

• Magnets are only attracted to ferromagnetic materials.

• There is no link between electricity and magnetism

Photographs and Movies

Put all photos in the class photo album and reference here.

References

Lenz Law of Electromagnetic Induction