HST2005 Experimental Work Group
Hst2005 Experiments
Millikan’s oil drop experiment
Charge
To calculate the charge of an electron
http://www.focuseducational.com/science/focus_on_fields.html
Electron diffraction
Wave particle duality
To show the wave properties of electrons
Electron Waves
Young’s slits
Electron diffraction
Calculating electron velocity
Photoelectric effect
Particle nature of light
To use visualize the Photoelectric Effect by using a larger object
Photoelectric effect
Particle nature of light
To use a zinc plate and an UV light to demonstrate the Photoelectric Effect
UV source should be behind glass
Alpha scattering
Radioactivity
To demonstrate the Rutherford model of the atom
http://www.fable.co.uk/media/ip/ipexamples/alpha.htm
Resolution
Detectors
To show that high resolution means high energy
http://www.immersiveeducation.com/uk/Krucible_Default.asp
smoke detector
Particles
Know practical use of Alpha-particles
http://home.howstuffworks.com/smoke.htm/printable
Moon experiences
detector
Know cosmic rays and measure several quantities about muons
http://class.phys.psu.edu/p559/Manuals/muonMIT.pdf
www.particle.kth.se/~pearce/muonlab/muonlab.pdf
www.physics.uiowa.edu/~fskiff/Physics_132/Lab%20Manual/B6Muon.PDF
Quadruple magnet focusing
Accelerator physics
Use light as an analogy of the particle beams to see how focusing can take place.
Mhammerich@vip.cybercity.dk
An accelerator in your living room.
Accelerator physics
To demystify beam accelerator concept and work with Lorenz force
Collision experiments with magnets.
Particle physics
Grasp the idea of probing matter with particles
Mechanical oscillations
Accelerators
To explain natural frequency an free vibrations
Resonance and damping of a hacksaw blade
Accelerators
To explain natural resonance and free vibrations
Investigating resonance
Investigating damping
Electrical oscillators
Accelerators
To explain electrical resonance and to relate it to beam acceleration
Page 1 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Light Emitting Diodes
Area:
Quantum Energy/Fundamental Constants
Measure the voltage to light different color diodes to determine the electrical energy required and
compare it to the energy associated with the frequency of the diode color. Plot the electrical energy
vs the frequency to determine Planck’s constant.
http://www.cns.cornell.edu/cipt/labs/lab-index.html
The Phantastic Photon
Quantum Nature of Light. Threshold frequency
Using super-bright LEDs of different colors, relate light color to energy and examine the minimum
frequency (color) needed to activate fluorescent paints.
http://www.cns.cornell.edu/cipt/labs/lab-index.html
Building a Cloud Chamber
Detectors
To use a cloud chamber to observe cosmic rays
http://www.cns.cornell.edu/cipt/labs/lab-index.html
Page 2 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Millikan’s oil drop experiment
Charge
To calculate the charge of an electron
Simulation
Pupils change the voltage on the plates and measure time. They can then
Description:
process the data to find a value for e.
Resources: Focus on Fields
References: http://www.focuseducational.com/science/focus_on_fields.html
A very good simulation which gets across the experimental procedure. Theory and
data processing are covered well and results can be processed using a spreadsheet.
The exercise will take about half an hour.
Page 3 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Electron diffraction
Wave particle duality
To show the wave properties of electrons
Experiment
Electrons are accelerated in a cathode ray oscilloscope and hit a target.
Description: The pattern is displayed on fluorescent screen. The accelerating voltage can
be changed and diffraction pattern observed.
Resources: Cathode ray oscilloscope with target inside, high voltage supply, 5000V
References:
Electron Waves
Electrons can behave like particles; we can measure their mass and charge. There are
situations where they can behave like waves.
Young’s slits
Light diffracts when it goes through the slits. Where the light from
the slits overlap dark and light regions are formed on the screen.
Light regions occur where constructive interference occurs. Dark
regions occur where destructive interference occurs. The particle
model cannot explain this effect.
Electron diffraction
Filament
Graphite target
Electrons
Diffracted electrons
Heating circuit
Accelerating voltage
When electrons go through small gaps, such as the spacing between carbon atoms in
the graphite target, they can diffract.
The electrons are accelerated by the accelerating voltage, V a. which can only be
explained by a particle model. But the electrons are also diffracted by the graphite
Page 4 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
electron is given by:
  2d sin 
where
racted
d is the spacing of the atomic planes of graphite.
Calculating electron velocity
By conservation of energy separation
1
mv2  eVa
2
2eVa
v 
m


Separation, d
Electron waves movie shows individual photons.
Electron Waves.doc is a worksheet which could be used to explain electron
diffraction.
Page 5 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Photoelectric effect
Area:
Particle nature of light
Aims:
To use visualize the Photoelectric Effect by using a larger object
Type:
Analogy
Description: Simulation using Games Factory
Resources: Monkton Combe web site
References:
The particle nature of light is explained using a coconut. The coconut represents
the electron. The coconut will only be knocked off if a particle of sufficient energy hits
it. A particle of greater energy will only knock off one coconut, but it will move faster,
while an infinite number of particles with insufficient energy will not knock off an
electron.
Page 6 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Photoelectric effect
Particle nature of light
To use a zinc plate and an UV light to demonstrate the Photoelectric Effect
Experiment
When UV light is shone on a negatively charged zinc plate resting on an
electroscope, electrons are removed. Therefore, the charge on the zinc
Description:
plate decreases, which can be seen on the electroscope. When glass is used
to stop UV, then no decrease in charge, and no electron emitted
Resources: Zinc plate, gold leaf electroscope, leads, UV source, glass, gauze
References:
Safety
UV source should be behind glass
A difficult experiment to set up.
Page 7 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Alpha scattering
Radioactivity
To demonstrate the Rutherford model of the atom
Simulation
Alpha particles are fired at nucleus. Then the separation distance is changed
Description:
and the deflection angle is measured.
Resources: Interactive Physics
References: http://www.fable.co.uk/media/ip/ipexamples/alpha.htm
This could be run as a demonstration or the pupils can build the simulation themselves.
The simulation can be obtained from the web site.
Page 8 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Resolution
Detectors
To show that high resolution means high energy
Simulation
The object is placed in front of plane wave source. At large wave lengths
with respect to object the waves diffract round the object so the object
Description:
would not be detected. At short wave lengths with respect to object the
waves do not diffract so the object can be detected.
Resources: Krucible
References: http://www.immersiveeducation.com/uk/Krucible_Default.asp
Taking a section through the wave makes the effect much clearer.
Page 9 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
smoke detector
Particles
Know practical use of Alpha-particles
experiment
Studying a smoke detector we can see an industrial application particleDescription: nuclear physics. Maybe is possible to use the americium-source for studying
alpha-particles.
Resources: A smoke detector, of course!!
References: http://home.howstuffworks.com/smoke.htm/printable
Page 10 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Moon experiences
detector
Know cosmic rays and measure several quantities about muons
experiment
Using some simulation software we can do some experiments about cosmic
Description: rays and in particular muons. Velocity, decay time, and distribution
(angular...) can be measured
scintillators, photomultipliers, some electronic devices, a computer (see
Resources:
references)
http://class.phys.psu.edu/p559/Manuals/muonMIT.pdf
References: www.particle.kth.se/~pearce/muonlab/muonlab.pdf
www.physics.uiowa.edu/~fskiff/Physics_132/Lab%20Manual/B6Muon.PDF
Page 11 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Quadruple magnet focusing
Accelerator physics
Use light as an analogy of the particle beams to see how focusing can take
Aims:
place.
Type:
Analogy experiment, at school or at CERN
Pupils will see that a beam of light can be confined and relayed through a
Description:
series of lenses.
At least two positive and two negative lenses of same focal length in
holders. Light source. Lenses can be taken from inexpensive “supermarket”
Resources:
glasses.
Light source.
References: Mhammerich@vip.cybercity.dk
Setting: In accelerators you need to focus the particle beam all the time or else the
charged particles will spread due to electrostatic repulsion, interaction with magnet
fields from induced currents in the beam pipe, or simply by falling onto the bottom of
the beam pipe. Therefore you need to be able to refocus the beam. Unfortunately the
magnets used for this can only focus in one direction, and will defocus in the other.
Therefore accelerator constructors place magnets along the beam so that every second
magnet focuses and every other defocuses.
In analogy to this we can use alternating positive and negative lenses placed at a
distance smaller than the focal length to see that such a system keeps the light beam
along the axis.
Description: Make a light beam. Place a positive lens in the beam. Place a negative lens
with the opposite focal length at a distance a little less than the focal length from the
first. Continue like this with as many lenses as you have. Use a white card at various
places in the beam to see that the beam is confined. Try to change the separation and
see what happens.
Variations: Use identical (inner rim-) toroidal lenses perpendicular to each other in
order to emulate the CERN magnets better and to see that you can change the
astigmatism along the beam.
Applications: Similar lens systems are used in periscopes and endoscopes to relay the
image to the viewer. Here they are called relay lens systems.
Page 12 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
An accelerator in your living room.
Area:
Accelerator physics
Aims:
To demystify beam accelerator concept and work with Lorenz force
Type:
Experiment
Description: Play with magnets around a CRT and record what happens
Resources: In simplest form: TV set, magnet.
References:
Setting:
A charged particle accelerator like the LHC machine works by accelerating charged
particles with an electric field and steering them around with magnetic fields. This is
exactly how the CRT in your television set works.
Directions CRT from a television
1) Hold a magnet a various distances from a TV screen and see that the image is
deflected. Note the direction of the deflection and correlate this with the
direction of the magnetic field.
2) Place a CRT between Helmholz coils and note how much the central part of the
image is deflected as function of the current in the coils.
3) Strip the cabinet off a TV set so that magnets can be placed at other places
nearer to the tube. Modify the set so that the accelerating voltage can be
measured and changed. See that the deflection is smaller for higher voltage.
(CERN has had such a set, I do not know if it exists any more.)
Do 2) and 3) with the CRT of an oscilloscope
Page 13 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Collision experiments with magnets.
Particle physics
Grasp the idea of probing matter with particles
Analogy
Students will shoot flat disk shaped magnets onto a hidden target. Analysis
Description:
should reveal some of the structure of the target.
Resources: Ferrite disk magnets. Ca. 25dia.X3mm end magnetised, flour
References:




Rutherford experiment analogy: one single fixed magnet as target
Knocking out electrons analogy: a single non-fixed magnet as target
Proton/quark-structure analogy: two or three fixed magnets as target.
Fission analogy two non-fixed magnets glued so lightly together that they can be
knocked apart. Projectile nonmagnetic (neutron).
Notes: All magnet fields must be in the same direction in order to have repulsive
Forces
- A more modern detector analogy would be to have rings of flour (tracking) and
iron filings ( EM-calorimeter)
- The students should be helped to discover the notion of the impact parameter.
- A slightly modified ball launcher for free fall experiments can be used to provide
“monoenergetic projectiles” A rubber band launcher can serve the same purpose.
Page 14 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Mechanical oscillations
Area:
Accelerators
Aims:
To explain natural frequency an free vibrations
Type:
Experiment
Description: Mass oscillates on a spring or a pendulum
Resources: Slotted weights, spring, stop watch, ultrasound ranger, etc
References:
Measure the natural frequency of a mass on a spring or the period of a pendulum and
relate it to the frequencies required to speed up a particle beam in an accelerator.
Page 15 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Resonance and damping of a hacksaw blade
Accelerators
To explain natural resonance and free vibrations
Experiment
A hacksaw is vibrated at different frequencies, while measuring the
Description:
amplitude of oscillation.
Oscillator, signal generator, hacksaw blade, cards of different mass,
Resources:
ultrasound ranger
References:
The hacksaw blade is attached to the top of the mechanical oscillator. The frequency
of the oscillator is controlled by the signal generator. The amplitude can be measured
using a ruler or the ultrasound ranger.
Investigating resonance
 Change frequency, measure amplitude. Pupils find resonance frequency, Q-factor,
and level of damping in system.
 Change mass of hacksaw blade by adding blu tack and investigate the effect on
resonant frequency.
Investigating damping
 Pupils change size of card on end of hacksaw blade. They relate this to amplitude
at resonance. A larger card has extra mass and will reduce the natural frequency
as well.
Page 16 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Aims:
Type:
Electrical oscillators
Accelerators
To explain electrical resonance and to relate it to beam acceleration
Experiment
Set up an inductance, capacitance, and resistance circuit and investigate
Description:
resonance.
Resources: Signal generator, variable capacitor, inductor, CRO
References:
RLC circuits are important in understanding the way beam acceleration is controlled.
Page 17 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Hst2005 Experiments
Name:
Area:
Light Emitting Diodes
Quantum Energy/Fundamental Constants
To see relationship between electrical energy and energy of
Aims:
photons/Calculate Planck’s constant
Type:
experiment
Measure the voltage to light different colour diodes to determine the
electrical energy required and compare it to the energy associated with the
Description:
frequency of the diode colour. Plot the electrical energy vs. the frequency
to determine Planck’s constant.
Resources: See reference
References: http://www.cns.cornell.edu/cipt/labs/lab-index.html
 This reference contains teacher information about diodes, purchase of materials,
and student worksheets for this lab.
 Light emitting diodes (LEDs) are increasingly being used as indicators in
electronic devices and as efficient light sources such as traffic lights. Using
super-bright LEDs, students investigate the conversion of electrical energy into
light and vice versa. By measuring and comparing the energy lost by each
electron with the frequency of the emitted light for several LED colours students
estimate Plank's constant, a fundamental number of quantum mechanics.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
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Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Practical Resources For Particle Physics
Name:
Area:
The Phantastic Photon
Quantum Nature of Light. Threshold frequency
Using super-bright LEDs of different colours, relate light colour to energy
Aims:
and examine the minimum frequency (colour) needed to activate fluorescent
paints.
Type:
Experiment
Students will shine different colour LED’s onto glow-in-the-dark tape and
onto surfaces painted with fluorescent paints to see which colours cause the
Description:
surfaces to glow. Light intensity can be varied to show the relationship to
threshold frequency.
Resources: See reference
References: http://www.cns.cornell.edu/cipt/labs/lab-index.html
 This reference contains teacher notes and information about where to get
material
 Student worksheets and post-lab and pre-lab questions.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Page 19 of 20
Teacher’s Lab 06/02/16
HST2005 Experimental Work Group
Practical Resources For Particle Physics
Name:
Area:
Aims:
Type:
Building a Cloud Chamber
Detectors
To use a cloud chamber to observe cosmic rays
Experiment
By using dry ice to super cool isopropyl alcohol the paths of cosmic rays can
Description:
be seen in the classroom
Resources: See reference
References: http://www.cns.cornell.edu/cipt/labs/lab-index.html
This reference provides:
 An inexpensive source for cloud chambers
 Extensive background and references about cosmic rays
 Helpful teacher’s notes and directions
 Student lab worksheet
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
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Teacher’s Lab 06/02/16