Magnet Madness Four Fun Experiments Using Powerful Magnets Subject(s)

magnet madness four fun experiments using powerful magnets subject(s): science, design & technology, engineering approx time:

Magnet Madness
Four fun experiments using powerful magnets
Subject(s): Science, Design & Technology, Engineering
Approx time: 60 mins
Key words / Topics:
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electromagnetism
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electromagnetic induction
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chaos theory
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magnetic fields
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applications & implications of science
Suggested Learning Outcomes
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Understand practical applications of magnets and magnetism
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Understand how electromagnetic induction works
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Understand the scientific principle of ‘chaos’
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Understand how magnetic fields penetrate the human body.
Introduction
This activity sheet was developed with the support and participation
of the School of Engineering at Cardiff University (www.engineering.cardiff.ac.uk).
Magnets are objects that produce a magnetic field that can either
attract or repel other magnetic materials. This has many potential
uses, such as in power generation, speaker design and advanced
transport systems, such as MAGLEV trains.
This is a series of practical experiments that demonstrate various
different scientific principles related to magnets and magnetism.
Purpose of this activity
These activities provide a quick, engaging set of tasks designed to
demonstrate various theories related to the use of magnets, such as
electromagnetic induction, chaos theory and magnetic fields. Although
mainly designed as science activities, they could also be used as an
introduction to power generation or the potential uses of magnets in
Design and Technology and Engineering projects.
Activity
Teacher notes
Introduction to magnet kit and safety
Introduce the kit to be used in the experiments and the health and
safety rules to be followed when using magnets (the resources section
of this document contains the details of the items of kit needed).
Learners should follow the following set of instructions to
successfully conduct each experiment:
Experiment 1: Dropping magnets down a tube
1.
Conduct a ‘free-fall’ test. Drop the magnets through a height of
around 20 cm. Try to measure the time taken for the magnets to
fall.
2.
Drop the magnets down the plastic tube. Describe the differences
observed compared to the ‘free-fall’ test. Try to measure the time
taken for the magnets to fall through the plastic tube.
3.
Drop the magnets down the copper tube. Measure the time taken for
the magnets to fall through the copper tube. Describe what happens
and explain your observations. In your explanation try to answer
the following questions:
a.
What determines the speed at which the magnet falls?
b.
Why is the underlying scientific principle in action here so
important for our everyday lives?
Experiment 2: The chaotic pendulum
1.
Carefully separate the two magnets by sliding them apart.
2.
Fix the magnets to a flat surface using blu-tack. They should be
placed approximately 6 cm apart.
3.
Make a pendulum using a steel nut as the pendulum’s “bob” (the bit
that swings), tied to a 50 cm long piece of cotton thread
supported vertically above the pair of magnets.
4.
Adjust the length of string so that the bob swings about 1 cm
above the floor level at its lowest point.
5.
Observe and describe the motion of the pendulum. Eventually it
should come to rest near one of the magnets. Can you predict which
one, based upon the position from which the pendulum started
swinging?
Experiment 3: “Aaarrgghh!!! Spider!”
1.
The two magnets are so powerful that their magnetic fields are
still quite large even a few cm away from them. To demonstrate
this, place one of the magnets in the palm of your upturned hand
and then move the other magnet underneath your hand.
2.
You should find that the magnet in your palm moves, as it is
attracted to (or repelled by) the magnet underneath.
3.
Place an inanimate object, such as a plastic spider, onto one of
the magnets. Try to make it move as if it is alive!
The supporting PowerPoint contains instructions for completing
the experiments. This can be shared with learners via a
projector/interactive whiteboard.
Experiment 1
This experiment demonstrates the principle of electromagnetic
induction, which is the conventional way of generating electricity.
When dropped down the copper tube, the falling magnet induces an eddy
current around the tube wall that produces an upwards force on it.
This
exactly balances gravity, causing it to fall with constant velocity
(by Newton’s first law of motion). The time taken for it to fall
through the tube is proportional to the electrical conductivity of the
tube wall. This can be tested by dropping the magnet down tubes of the
same size but made of different metals. Copper is second only to
silver in having the highest conductivity at room temperature.
The plastic tube cannot support an electrical current, allowing the
magnet to accelerate under gravity in the usual way. Simple
calculations show that it should take 0.2 s to free-fall by 20 cm -
too fast to measure easily.
A longer piece of straight copper pipe than that suggested can be
cheaply obtained from most hardware stores. A piece that is at least 1
m in length will give an even more impressive experimental result.
Experiment 2
This demonstrates the general principle of ‘chaos’. That is the
chaotic (i.e. apparently random) motion of the pendulum before it
finally settles down. Starting the pendulum swinging near one magnet
is no guarantee that it will settle next to this magnet. You could
further explain how chaos has huge consequences for our physical
world.
The initial separation the magnets (step 1) is best done by sliding,
rather than pulling them apart.
When supporting the magnets vertically (step 2) a chair works well for
this purpose.
Experiment 3
This demonstrates that magnetic fields penetrate the human body and
are harmless. An example, such as medical imaging machines (e.g. MRI
scanners), could be shared with learners for context. These use very
large magnetic fields to affect the spins of the nuclei of the atoms
present within the body, allowing images of internal organs to be
produced. This could also be compared this with the harmful
alternative of using X-rays.
Step 3 works well when moving such objects around on table tops, using
a magnet below.
Suggested lesson format
These experiments can be completed individually by students, or in
small groups. They could be delivered as single integrated lesson
spilt into three parts:
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Part A - Newtonian Interaction
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Part B - Coulomb Interaction
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Part C - combined/unifying approach
Health and safety
It is very important that health and safety rules are followed when
working with magnets. The suggested magnets for this activity are made
from an alloy of the rare earth metal neodymium (Nd), which is used to
make some of the strongest permanent magnets. When using them with
students, the following should be implemented:
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Keep them away from heart pacemakers
*
Ensure students do not attempt to swallow them
*
Explain to students that they are brittle and can shatter into
very sharp bits if allowed to fly together
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Keep them away from credit cards, iPods, mobile phones and TVs
Differentiation
Basic
Extension
Organise as group activities with higher ability leaners supporting
lower ability learners.
Use sentence starters and prompts to assist learners with describing,
explaining and discussing the results of each experiment.
Use a technician to pre-assemble the pendulum for experiment 2.
1.
Discuss current and potential future engineering applications of
electromagnetic induction.
2.
Research the consequences of ‘chaos theory’ in the physical world.
3.
Investigate and explain the applications and advantages of using
magnetic fields in healthcare.
Resources
Required files
Projector/Whiteboard
Magnet kit
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2 neodymium magnets - 12mm diameter x 2mm thick e.g. F312-20 from
www.first4magnets.com
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1 off 15mm diameter x 200mm length plastic radiator pipe sleeves
e.g. 0000004002178 from B&Q DIY www.diy.com
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1 off 15mm diameter x 200mm length copper plumbing pipe (cut to
200mm length plus deburred internal openings) e.g. 5034579002276
from B&Q DIY www.diy.com
Cost to make 10 kits from above supplies:
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Magnets £10
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Plastic pipes £10
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Copper pipes £10
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Total cost is approximately £30 (or £3 per kit)
Additional resources
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Sticky tape, blu-tack, steel nut, cotton thread and chairs
Magnet madness (Presentation)
Additional websites
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GCSE Bitesize: Introduction to magnets and their properties.
https://www.bbc.co.uk/education/guides/zxxbkqt/revision
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Howstuffworks: How MAGLEV trains work
https://science.howstuffworks.com/transport/engines-equipment/maglev-train.htm
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GCSE Bitesize: How electromagnetic induction is used to create
electricity.
https://www.bbc.co.uk/bitesize/guides/zqys97h/revision/1
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Wikipedia: An introduction to ‘chaos theory’.
https://en.wikipedia.org/wiki/Chaos_theory
Related activities (to build a full lesson)
Starters (Options)
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Research the basic properties of magnets
Main (Options)
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ACTIVITY: Magnet Madness
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ACTIVITY: Motor Madness
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ACTIVITY: Overcoming friction
Plenary
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Opportunities within activity for presentations and peer/self
assessment of experiment outcomes
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Reflection on Objectives and PLT skills used
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Investigate practical uses of the theories explored
The Engineering Context
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Applications of magnets and magnetism
Curriculum links
England: National Curriculum
Science
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KS3 2a, 2b, 2c, 2d, 2e, 27h, 37a, 37a, 37d
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KS4 Magnetism and electromagnetism
Design & Technology
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KS3 1a, 3a, 3b, 4a
GCSE
AQA Engineering
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3.1.3, 3.3.2
AQA Design and Technology
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3.1.1, 3.1.2
Edexcel Design and Technology
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1.2.2b, c, 1.3.2
Eduqas Design and Technology
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2.1 Core: 3
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2.2 Core: 2
OCR Design and Technology
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1.1a i, 3.2
AQA Physics
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4.5.1.2, 4.7.1, 4.7.2
Edexcel Physics
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9.1a, 12.1, 12.2, 12.3, 12.4, 12.7, 12.11, 13.1P, 13.2, 13.3P
Eduqas Physics
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3.1a, 8.1a, 8.1b, 8.2e
OCR Gateway Science Physics A
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P2.2a, P4.1a, P4.1e, P4.2a, P4.2d
OCR Twenty First Century Science Physics B
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P2.1.1, P2.2.3, P3.5.1, P3.5.2, P3.6.1, P3.6.4, P3.7.1, P4.1.3
AQA Combined Science: Synergy
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4.6.1.1, 4.6.3
AQA Combined Science: Trilogy
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6.5.1.2, 6.7.1, 6.7.2
Edexcel Combined Science
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9.1a, 12.1, 12.2, 12.3, 12.4, 12.7,12.11, 13.2
Eduqas Combined Science
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3a, 8.1a, 8.1b, 8.2e
OCR Gateway Science Combined Science A
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P2.2a, P3.3a, P3.3c, P3.3h, P3.3k
OCR Twenty First Century Science Combined Science B
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P2.1.1, P2.2.3, P3.4.1, P3.4.2, P4.1.2
Northern Ireland Curriculum
Science
Developing pupils’ Knowledge, Understanding and Skills
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develop skills in scientific methods of enquiry to further
scientific knowledge
and understanding: planning for investigations, obtaining evidence,
presenting and interpreting results;
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Learn about forces and energy
Technology & Design
(Objective 2) Developing pupils as Contributors to Society
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Explore technical inventions and designs that have met a social
need cost-effectively
Scotland: Curriculum for Excellence
Sciences
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SCN 4-08a 4-20a
Technologies
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TCH 3-01a
Wales: National Curriculum
Design and Technology
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KS3 Skills (Designing 2)
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KS3 Range (Systems and controls 16)
Science
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KS3 Skills (Enquiry 1, 2)
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KS3 Range (How things work 3)
Assessment opportunities
Assess learner responses when describing and explaining the results of
each experiment.
Provide verbal feedback to guide learning during the activities.
Self and peer assessment of experiment outcomes.
Personal, learning & thinking skills (PLTS)
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Independent Enquirers
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Effective Participants
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Team Workers