Download Floating Garden of Magnets

Curriculum topics:
 Magnetic Fields
 Crystal Patterns
 Atoms and
Molecules
 Geometry
FLOATING GARDEN
OF MAGNETS
Subject:
Physical Science
Investigate magnetism and
model crystal structures
Grade range: 2 – 12
Magnets floating in water move easily and adjust their position
based on changes in the number and location of other magnets
around them. Beautiful designs emerge as magnets float to find
their positions in the pattern. This activity demonstrates the effects
of magnetic fields and also illustrates how crystal molecules form.
In the Floating Garden, the poles of the magnets are oriented in
the same direction (see illustration below). As a result, the
magnets repel, and the foam rings drift apart.
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Teaching (RAFT) helps
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learning experience
through affordable
“hands-on” activities
that engage students
and inspire the joy and
discovery of learning.
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Magnets provided in the RAFT Kit should be handled only by
individuals 8 years and older.
WARNING:
For more ideas and to
see RAFT Locations
www.raft.net/visit-raft-locations
© 2014, RAFT
Swallowed magnets can stick together across intestines
causing serious infections and death. Seek immediate medical
attention if magnet(s) are swallowed or inhaled.
http://www.raft.net/raft-idea?isid=162
Materials required
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Tiny, rare earth magnets, 20+
Coffee stirrer straws, 4+
Small foam pieces that float, 20+
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High-sided circular dish, such as a pie plate
(must be non-magnetic)
Optional - Overhead projector
How to build it
1
Cut coffee stirrer straws into 2.5 cm (1”) sections. Insert each rare
earth magnet into the end of a straw section, 1 magnet per section
(NOTE: the fit should be tight). All magnets should be inserted
with the same orientation (same pole goes into the straw first).
The easiest way to do this is to have the magnets attracted to
each other end to end in a row. Hold one end of the row and insert
one magnet into a straw. Pull the rest of the row away and, using
the same end of the row, repeat as needed. If needed, use a
toothpick to push out any reversed magnets and reinsert.
To make inserting the magnet
easier, lightly pinch the straw
end to create an oval opening.
First straw
Second straw
2
Use a pointed object, such as a pencil, to make an opening smaller than the size of the
straw in the center of the foam piece. (RAFT Kit pieces already have holes.)
3
Insert the straw/magnet combination about halfway into the opening in the foam piece.
Repeat for each foam piece.
4
Add just enough water to the dish to float the magnets. (If using an overhead projector, use a
clear dish. Avoid spilling any water on the projector.)
Note: Magnets may damage items containing magnetic materials such as audio/video tapes and
credit cards. Magnets should be kept away from these items.
To do and notice
1
Float one of the magnets in the water. If needed, adjust the straw in the foam piece or add water
until the magnet floats freely in the dish.
2
Add or remove magnets one at a time. Predict what will happen before each change. Then,
observe what actually happens. Make notes and sketches to record results.
Floating Garden of Magnets, page 2
© 2014, RAFT
The science behind the activity
Background Information:
Scientists have observed that all material (matter) is a combination of 100+ basic building blocks
called elements. Every element (such as gold) has a unique combination of properties.
The smallest piece of an element that still possesses its properties is an atom. Every atom is made up
of 3 types of smaller particles: electrons spin around a tightly-packed core (nucleus) which contains
protons and neutrons. Two or more atoms can combine to form molecules - the smallest pieces of
more complex types of matter.
Electrons and protons have an electrical property called charge. Charges can be positive (+) or
negative (-). When a charged particle moves, a magnetic field is created around the particle. The
magnetic field is conceptualized as a pattern of loops going out from the particle, looping into space,
curving back to enter the particle on the opposite side. Individual loops (magnetic field lines) are
continuous (unbroken) and do not cross. In an atom or molecule, the magnetic field lines are usually
oriented in many different directions, and so there is little or no overall magnetic field. These materials
are considered to be non-magnetic. Iron, nickel, cobalt, and many materials made from them are
magnetic. Magnets which contain the rare earth elements neodymium or samarium have particularly
strong magnetic fields.
Magnetic Field Lines
Key Content:
All magnets have at least two poles: a north pole (N) and a south pole (S). The poles are areas
where the magnetic field lines are most closely concentrated. For magnets, the poles are usually on
opposite ends or sides.
Opposite poles (S/N) attract each other. Like poles (N/N or S/S) repel. Magnets will repel when
their like poles are near each other. The attractive and repelling forces decrease as the distance
between the magnets increases (as shown below).
N
S
N
S
S
N
Short distance = strong force
S
N
Long distance = weak force
In the Floating Garden of Magnets, the “like” poles of the magnets are aligned. As a result, the magnets
repel one another and the foam rings drift apart (see illustration on page 1).
Floating Garden of Magnets, page 3
© 2014, RAFT
Curriculum
Standards:
Learn more

Electric or magnetic
interactions between
objects not in contact
with each other
(Next Generation
Science Standards:
Grade 3,
Physical Science, 2-3;
Middle School,
Physical Science, 2-5)
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Start the activity with 12 -14 magnets evenly spaced around the edge of the
dish. Note how new magnets arrange themselves as they are added.
Place a large magnet over the center of the dish. Observe the effect on the
pattern.
Remove and re-insert one magnet with its poles reversed. Floating magnets
with the reverse magnetic orientation will be attracted to it. This models the
way many crystals are formed.
Magnets
(Next Generation
Science Standards:
Grade 3,
Physical Science, 2-4;
Middle School,
Physical Science, 2-3)
Structure of molecules
(Next Generation
Science Standards:
Middle School,
Physical Science, 1-1)
Related activities: See RAFT Idea Sheets:
Forces & Motion
(Next Generation
Science Standards:
Grade 3, Physical
Science, 2-1 & 2-2;
Middle School,
Physical Science, 2-2)
Floating Compass –
http://www.raft.net/ideas/Floating Compass.pdf
Magnetic Field Line Viewer –
http://www.raft.net/ideas/Magnetic Field Line Viewer.pdf
Magnets Around the Rim –
http://www.raft.net/ideas/Magnets Around the Rim.pdf
Science and
Engineering Practices
(Next Generation
Science Standards
Grades 2 – 12)
Mini Magnet Wands –
http://www.raft.net/ideas/Mini Magnet Wands.pdf
Resources
Visit www.raft.net/raft-idea?isid=162 for “how-to” video demos & more ideas!
See this website for more information on the following topics:

Additional standards at:
http://www.raft.net/raftidea?isid=162

Physicist Paul Doherty shares his version of this activity at –
http://www.exo.net/~pauld/activities/magnetism/Garden of Magnetsmini.html
Videos on Electricity and Magnetism from the Khan Academy –
https://www.khanacademy.org/science/physics/electricity-and-magnetism
Acknowledgements:
Based on the work of Michael Faraday (1791-1867) and Paul Doherty.
Floating Garden of Magnets, page 4
© 2014, RAFT