Email icon

Eddy Current Tubes (Super-Large)

  • Copper Eddy Current Set 18 cm (7 in.)
    Item #: ED-100
  • - +
  • Aluminum Eddy Current Set 36 cm (15 in.)
    Item #: ED-125
  • - +
  • Copper Eddy Current Set 60 cm (24 in.)
    Item #: ED-140
  • Out of Stock
Large diameter, thick-walled copper and aluminum Eddy Current Tubes.

Description

As you drop neodymium magnets down these large diameter, thick-walled copper and aluminum tubes, you can watch them twist and turn as they slowly fall. A moving magnetic field creates a surprisingly strong opposing magnetic field in these tubular conductors. Each tube kit listed below contains a thick-walled Eddy Current Tube and sample neodymium magnets. Please see below for details. The length of the heavy-walled aluminum tube is calculated so that magnets take the same time to fall as the shorter copper tube.

Material

Approx. Dimensions

Approx. Fall Time

Included Neodymium Magnets

Item Number

Copper

18 cm (7") 34 mm Dia

4 sec

2 rings

ED-100

Aluminum

36 cm (15") 34 mm Dia

4 sec

2 rings

ED-125

Copper

60 cm (24") 26 mm Dia

18 sec

1 sphere

ED-140

Read more on our Blog - Focus on Lenz's Law

Read more on our Blog - Bring Some Magic Into Your Classroom!

Read more on our Blog - Eddy Current Tubes with Video

Video




Lesson Ideas

Download the pdf of this lesson!

  1. An eddy current is a current set up in a conductor in response to a changing magnetic field. Lenz's law predicts that the current moves in such a way as to create a magnetic field opposing the change; to do this in a conductor, electrons swirl in a plane perpendicular to the changing magnetic field.

    Because the magnetic fields of the eddy currents oppose the magnetic field of the falling magnet; there is attraction between the two fields. Energy is converted into heat. This principle is used in damping the oscillation of the lever arm of many mechanical balances. At the end of the arm a piece of flat aluminum is positioned to move through the magnetic field of a permanent magnet. The faster the arm oscillates, the greater the eddy currents and the greater the attraction to the permanent magnet. However, when the arm comes to rest, the attraction is negligible.

  2. If a single neodymium magnet has the same mass as a single cow magnet, the neodymium magnet will fall at a slower rate because its magnetic field strength is greater.

  3. Two neodymium magnets fall at a slower rate than one because the magnetic field strength has increased. The time of fall within the tube increases with the addition of other magnets. There is a point where the effect of the increase in mass becomes greater than the increase in magnetic field strength. Then, the group of magnets falls faster.

  4. Thicker tubes increase the falling time due to stronger eddy currents from the greater number of conducting electrons. Suggest an experiment to determine the thickness of the tube by determining the rate of fall of a magnet within the tube.

  5. Determine the time for one magnet to fall through the 7 inch copper tube and measure the time for the same magnet to fall through the 15 inch aluminum tube. The falling times should be approximately the same. Relate the length of the tubes to the conductivity of the metals.

Areas for investigation:

  1. How will magnets of different magnetic field strengths affect falling time? Try dropping 2 cow magnets that have the same mass but different magnetic field strengths down the same tube one at a time.
  2. How does the falling time of neodymium magnets compare to the falling time of cow magnets?
  3. Allow multiple neodymium magnets to attract together. How does changing the number of magnets affect the falling time?
  4. Do both single and multiple neodymium magnets fall down the tube at a constant velocity?
  5. How does changing the thickness of the tube affect falling time?
  6. How does changing the length of the tube affect falling time?
  7. How does changing the material of the tube affect falling time?
  8. How does cooling the tube down with liquid nitrogen affect falling time?
Write a Review

Reviews

12 reviews
Instructor
Review star icon Review star icon Review star icon Review star icon Review star icon Aug 22, 2016
Awesome
thomas hussey

Was this review helpful?

0   0

A Wonder
Review star icon Review star icon Review star icon Review star icon Review star icon Jun 16, 2016
Real magic. Blows everyone's mind who's seen it. Even more impressive with a spherical magnet.
James

Was this review helpful?

1   0

eddy currents
Review star icon Review star icon Review star icon Review star icon Review star icon Sep 16, 2015
Great for one person to see the effect. I have the audience come up one at a time to see the effect. It comes with the magnet but I will use a larger magnet for a better performance. This set is good but I wish I recommend the longer copper tube for the best demonstration. Like!
Mark Carter

Was this review helpful?

0   0

Fun Fields
Review star icon Review star icon Review star icon Review star icon Review star icon Aug 20, 2015
The magnets moving through the Eddy Tube are fun to observe and easy to contrast to non-magnets dropped through.
Darla Dee Turlington

Was this review helpful?

0   0

Great product!
Review star icon Review star icon Review star icon Review star icon Review star icon May 28, 2015
This is a great educational demo product that shows the interaction of a magnetic field and the induced electric field as Faraday and Lenz discovered in the 1830's. This is a dramatic demo that is sure to impress even someone who is aware of the science behind it.
Jerry Petrey

Was this review helpful?

0   0

Nice eddy current demo, needs larger magnet
Review star icon Review star icon Review star icon Review star icon Review star icon Mar 22, 2014
The large size copper tube is perfect for generating large eddy currents and really slows down the magnet. My only quibble is that the supplied neodymium magnet is too small for the barrel size. It's a 3/4" donut magnet whereas the barrel of the tube is 1". If the magnet was closer to 1" the effect would have been even more awesome. However, still worth the purchase price, so I recommend it!
Lyndie Chiou

Was this review helpful?

0   0

Great Product
Review star icon Review star icon Review star icon Review star icon Review star icon Mar 11, 2014
Excellent service, found exactly what I wanted. This is an excellent tool to get anyone interested in science and physics.
Kevin Eckhart

Was this review helpful?

0   0

Very good copper tube
Review star icon Review star icon Review star icon Review star icon Review star icon Feb 26, 2014
I've bought the short copper tube: very heavy and thick walled. The NM in the package is not so strong and not so big: I use with this tube a NM sphere with 2,6 cm of diameter. With this sphere, the falling time is well over the 4 seconds indicated for the smaller neodymium disk! Wonderful effect!
Ruggero

Was this review helpful?

0   0

eddy tube
Review star icon Review star icon Review star icon Review star icon Review star icon Feb 20, 2013
The eddey current tubes were a hugh hit with my students. Like always, Educational Innovations came through with a great demostration equipment that is easy to use and really spark interest in my students.
Al Evans

Was this review helpful?

0   0

Captivating Magnet Races
Review star icon Review star icon Review star icon Review star icon Review star icon May 20, 2012
One of the first purchases I ever made from EI was the copper and aluminum tubes with equal drop times for the magnet. I use these every year in my Physics class and they never fail to astonish kids and keep them coming in at lunch to drop the magnets over and over.
Lissa Vincent

Was this review helpful?

0   0

Eddy Current Tubes
Review star icon Review star icon Review star icon Review star icon Review star icon May 16, 2012
I highly recommend these eddy current tubes. They are a lot of fun and everyone wants to know how they work. They make for fascinating demonstrations (and magic tricks).
Brian

Was this review helpful?

0   0

What, Come On!!
Review star icon Review star icon Review star icon Review star icon Review star icon May 16, 2012
Students really loved this one. They knew that magnets attract and even stick. Here they see that that same characteristic lets then "slip and slide". Great mind bender!
Roy

Was this review helpful?

0   0

Q & A