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Modeling Atoms : Mini Rutherford

Description: With the Mini Rutherford Activity, students deduce shapes and sizes of unseen objects by tracking the movements of objects they can see, in relation to the unseen object. By extension, this device is a useful analogy to Rutherford’s alpha scattering experiments and to atomic particle detection utilizing accelerators. (Since the particles are too small to be seen, it was necessary to deduce their sizes by other means in both of these instances.) This experiment is best used by students working in pairs.

rutherford

Grade Level
5-12

Disciplinary Core Ideas (DCI, NGSS)
5-PS1-1, MS-PS1-1, MS-PS1-4, HS-PS1-8

Time for Teacher Preparation
40-60 minutes – To make the Rutherford boards
40-60 minutes – To prepare for the classroom

Activity Time:
40-60 minutes (1 Class Period)

Materials

  • 5-10 blocks of various shapes 20 cm (8” x 10″ x 3/4″)
  • 5-10 30.5 x 30.5 cm (12” x 12” x 1/8”) masonite boards
  • Pkg./30-1.9 cm (3/4”) or (5/8”) marbles
  • Paper
  • Pen, marker, or pencil
  • Ruler
  • Student Data Collection Sheets

Safety

  • Students should use care when handling marbles
  • Students should not throw marbles
  • Students should avoid stepping on marbles

Science and Engineering Practices (NGSS)

  • Ask questions
  • Define Problems
  • Use Models
  • Plan and Carry out investigation
  • Analyze and interpret Data
  • Construct Explanations
  • Communicate Information

Cross Cutting Concepts (NGSS)

  • Patterns
  • Cause and Effect
  • Scale, Proportion, and Quantity
  • Systems and System Models

Objective
Students will try to determine the shape of an unknown object by using the scientific thought process of creating a hypothesis, then testing it through inference. It is based upon the Rutherford Gold Foil Experiment where scientists discovered that the structure of the atom includes the nucleus in the center surrounded by electrons in empty space. It is a great introduction to the scientific process of deducing, forming scientific theories, and communicating with peers. It is also useful in the mathematics classroom by plotting the angles of incidence and reflection

Background
From 1911 to 1913, British physicists Geiger and Marsden, working in the laboratory of Ernest Rutherford, conducted experiments with beams of positively charged, alpha particles to penetrate gold, silver, and copper atoms. They observed that most of the alpha particles went directly through the foil. However, some particles were deflected and others recoiled back toward the source. Rutherford systematically investigated the results Geiger and Marsden obtained with alpha particles; Rutherford concluded
that most of the mass of an atom is concentrated in a small region in its center, now called the nucleus.

Fundamental Particles Detection
Light has a wavelength of 10-7 m. Light microscopes enable us to view parts of a cell as small as 10-6 m. Electron microscopes enable us to see an image with a wavelength as small as 10-9 m. With the help of scanning electron microscopes, we can see fuzzy images of atoms. To detect a smaller image, such as a fundamental particle, we need to produce particles with greater energy, and thus, a shorter wavelength. The smallest fundamental particle is less than 10-18 m in diameter! Although scientists have not yet been able to actually see fundamental particles, they can infer the presence of these particles by observing events and applying conservation laws of energy, momentum, electric charges, etc. One way to do this is with a particle accelerator. Essentially, a
particle accelerator works by shooting particles at high speed toward a target. When these bullet particles hit a target, a detector records the information about the resulting event.

Necessary Components for Particle Detection
1. Bullet Particles. These can be either electrons, positrons (the anti-particle of an electron), or protons. The particles
are collected as follows:

  • Electrons are collected the same way a TV picture tube collects them; a metal plate is heated and electrons are emitted.
  • To obtain positrons, a beam of electrons collides with a target, resulting in a photon. From the photon, electrons and positrons may be formed and are separated by their charges in a magnetic field.
  • Protons are obtained by ionizing hydrogen gas. Ionization requires collisions at energy great enough to strip electrons from hydrogen, leaving protons.

2. An accelerator increases the speed of bullet particles to greater energy levels. The particles are accelerated with an electric field by riding on traveling electromagnetic (EM) waves. The EM waves are created in devices called klystrons, which are large microwave generators.

3. The steering device directs the bullet particles to their target. Magnets are used to steer the particles around a circular accelerator and to focus the particles so they will hit the target. The same magnets make positive and negative particles traveling in the same direction bend in opposite directions.

4. A target can be any solid, liquid, or gas, or another beam of particles.

5. A detector interprets the paths of the resulting particles once the bullet particles have collided with their target. Modern detectors have several layers, to detect the many particles produced in a collision event. A detector can be up to three stories tall. An advanced computer system is used to reconstruct the many paths of the particles detected in the layers associated with a collision. By viewing particle paths through each layer of the detector, scientists can determine the results of an event. Charged particles leave a track in the inner (tracking) layer of the detector. The positive or negative charge of the resulting particle can be determined by the direction it curves in a magnetic field. A particle with great momentum (speed x mass) will have a less curved path compared to one with less momentum. After a collision, electrons and protons will leave showers of particles in certain detector layers. Photons and neutrons travel a little further through the layers before their collisions create a shower of particles. Muons (one type of a fundamental particle), however, can be detected in the outer layer of a detector. They travel right through the inner layers with little or no interaction.


Teacher Lesson Plan:

Traditional
To make Rutherford boards:
Velcro, glue, or nail block shapes underneath the masonite boards. Note: Some hardware stores will cut shapes for you free of charge.

Potential Block Shapes:

Triangle, Square,Rhombus, Isosceles Trapezoid, Hexagon

Place the Rutherford boards on a large table or on the floor, obstructing the shapes from your students’ view. Place a piece
of paper on top of each Rutherford board. Beware: your students may be tempted to peek. The student activity, described in the accompanying worksheet, should take about five minutes to complete. The activity can be repeated several times during a class period, using different shapes and/or marbles each time. Some shapes are more difficult to detect than others.

NGSS Inquiry
Explain Rutherford’s experiment. Tell students that they will design their own experiment, using rolling marbles as alpha particles to discover the shape of a hidden geometric shape, which simulates the nucleus. You might suggest that the students experiment with rolling a marble at different angles at a straight surface and seeing the different ways the marble deflects.


Student Procedure

Using the Rutherford boards:
Middle School
Part 1

  1. Working in small groups, roll one of the marbles at the hidden object underneath the Rutherford board while one student draws the marble’s path in, and the deflected path out, on the piece of paper placed on the Rutherford board. Map the paths of the marbles that do not deflect or deflect slightly, as well. Make sure you roll the marble fast enough so that it makes a clean shot in and out.
  2. Repeat Step 1 as many times as needed to define the outline of the hidden shape, using the same size marble each time. Make sure you roll the marble from many points on each side of the board.
  3. Once you are satisfied that you know the shape of the object under the Rutherford board, draw the shape onto the piece of paper. (You might want to trace the shape from the paper with the outline formed by the collision paths).
  4. Before looking at the actual block shape, show your instructor the shape you have drawn. Then look at the block underneath the Rutherford board, and discuss any parts of the shape you have drawn that are ill-determined.
  5. Part 2: Have the instructor place a different block back under the Rutherford board (or switch boards if they are permanently attached). Place a clean sheet of paper on the top of the Rutherford board and repeat the procedure (Steps 1-4).

High School
Repeat steps 1-5 as per the Middle School procedure. Place the Rutherford board on a large piece of butcher paper, and then have the students record the shapes on the large paper. Do not put the paper on the board so that students must infer the shape from the surrounding angles of incidence/reflection.

Growing Irradiated Bean Seeds

Description: What happens to seeds that are exposed to very high levels of radiation? Will they grow normally?

plant growth

 

 

 

 

 

 

 

 

 

 

 

 

Grade Level

5-12

Disciplinary Core Ideas (DCI, NGSS)

5-PS1-3, 5-ESS3-1, 3-5 ETS1-1, MS-ETS1-2, MS-ETS1-3, HS-PS4-4, HS-ESS2-3

Time for Teacher Preparation

To gather materials and set-up

Activity Time:

1-2 Weeks Minimum. Passive observations as beans grow.

Materials

  • Pen, Marker, or Pencil
  • Student Data Collection Sheets
  • Mung bean seed
  • Irradiated Mung bean seeds (50,000; 100,000; 150,000 rad exposure)
  • Potting soil
  • Pots (2″ to 3″ pots)
  • Small metric rulers

Safety

  • Students should not put bean seeds, soil, pots, or metric rulers in their mouths due to choking hazard.
  • Students should not try eating bean seeds or irradiated bean seeds.

Science and Engineering Practices (NGSS)

  • Ask questions and define problems
  • Plan and carry out investigation
  • Analyze and interpret data
  • Use mathematics and computational thinking
  • Construct explanations
  • Argue from Evidence
  • Obtain, evaluate and communicate information

Cross Cutting Concepts

  • Patterns
  • Cause and Effect
  • Scale, Proportion, and Quantity
  • Energy and Matter: Flows, Cycles, and Conservation
  • Structure and Function
  • Stability and Change of Systems

Objectives

The students develop a procedure to study the effects of radiation on mung bean seeds and other irradiated seeds. Students will observe and record data on the germination and development of the plants. Student data, results, and conclusions will be presented, supported, and defended by the students to the class.

  • To define the terms radiation and irradiation
  • To determine how irradiation affects the growth of bean seeds
  • To determine how much radiation dose comes from nature and how much comes from the uses of radiation in society.
  • To compare data

Background

Irradiation is becoming increasingly more popular in the treatment of foods to kill bacteria, diseases and pests. A fear of radiation causes some people to believe that food that is irradiated becomes radioactive. The irradiated bean seeds in this experiment have been exposed to various levels of gamma radiation, but are not radioactive and are completely safe to handle.

You cannot tell how much radiation the seeds were given by looking at them. These seeds were harvested and irradiated after the plants were mature. However, you will be able to observe differences in the plants growing from these seeds. Each seed contains an embryo plant. When the gamma radiation passed through these seeds, it damaged some of the cells in the embryo. The greater the radiation, the more cells were damaged. Therefore, the resulting plants grown from seeds with greater exposures will show more abnormalities than those with lower exposures.


Teacher Lesson Plan:

Traditional

Split students into groups of four and give each group four sets of bean seeds (control; 50,000; 100,000; 150,000 rad). Have each group plant their seeds in separate pots and set up a table to chart and graph the growth of the seeds over the next couple of weeks. Students should record height and observations of their beans at least twice a week. Remind students to water their beans as frequently as needed in order to take care of their plants.

It might be helpful to stress that the beans have been irradiated, but are not radioactive.

Students may also grow the seeds in test tubes of water and plant them once they have germinated.

NGSS Guided Inquiry

Have students design an experiment to discover about how much radiation each of their seeds was exposed to.

Student Procedure

  1. Plant seeds into separate pots and water until the soil is moist. Alternatively, grow the seeds submerged in water inside of test tubes until they germinate and then pot them.
  2. Set up a data table to record height and observations of the bean seedlings. Observations should be made at least twice per week.
  3. Take care of your plants by watering them as frequently as needed.
  4. Graph data from your data table and deduce which seeds received which dose of radiation (control; 50,000; 100,000; 150,000 rad)
  5. Add a step to include listing the variables which must be controlled in this experiment.
  • Examples of this include:
  • exposure to sun or artificial light
  • temperature of the surroundings
  • whether seed is grown in soil or in water
  • the amount of water added to the soil (students should measure the added water in milliliters).

Data Collection

Student Data Collection Sheets

Post Discussion/Effective Teaching Strategies

Questions provided on the Student Data Collection Sheets

Questions

  1. What happened? Why do you think the things you observed occurred? Were your observations and conclusions different from other students? Why? Who’s “right?”
  2. 100,000 rads or 150,000 rads is enough to kill a human. Did it kill all the plants? What do you think are some possible explanations?

Assessment Ideas

  • Test the student’s observations against the actual irradiated exposure of each plant.

Differentiated Learning/Enrichment

  • Have students make slides of each of the beans for viewing under a microscope.
  • Try getting a couple more generations from the plants to observe successive generations.

Enrichment Questions

  1. If radiation increases on earth, what effects do you think it will that have on plant growth? On other organisms? On humans?
  2. What do you think happened to the cells of the irradiated Mung bean plants?
  3. Why do we use irradiation to prevent food from spoiling?

Further Resources

From Harvest to Home

Purchase Irradiated Mung Seeds through Ward’s Science (item #6730926)

Reference:

Los Alamos National Laboratory (1992). Detecting the Invisible: The SWOOPE Radiation and Radon Discovery Unit

Did You Know? Bookmarks

Grade Level: 5 – 8

These 2 ¼ x 8 inch bookmarks with Did You Know? messages make a perfect give-a-way for your students.   Each pack includes 25 bookmarks of six (6) different nuclear messages.  Messages include:  Radiation is a natural part of our world,  medical applications, nuclear power, arts and science, agriculture, and safety. The bookmarks are also available in Arabic.

This item is sold in assorted packs of 150 (25 of each of the 6 titles).

$22.69 each ($20.42 for American Nuclear Society members). To order in English or Arabic, please visit the ANS Store.

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Teacher Resource Guide: Detecting Radiation in Our Radioactive World

Grade Level: 5-12

The ANS Center for Nuclear Science and Technology Information is pleased to introduce its new teacher resource guide, Detecting Radiation in Our Radioactive WorldThis guide was inspired by our national teacher workshop by the same name. It includes units on: Modeling Atoms,  Making Atoms Visible, Personal Dose, Irradiation and Benefits, Half-Life, Measuring and Units (using a Geiger counter),  Fission, Decay Chains, Radiation Types, Waste, and Energy Production

The guide can be purchased for $15 each($13.50 for American Nuclear Society members). To order Item #750091, please visit the ANS Store.

Register to Access the Detecting Radiation in Our Radioactive World® Teacher Resource Guide for FREE!

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Isotope Discovery Kit

isotopekit1Grade Level: 9-12

Shelve the dry textbooks and one-dimensional charts.  You will energize your classroom and make science come alive using the Isotope Discovery Kit!

Developed by nuclear engineer and ANS member Bill Wabbersen, the kit provides students with a clear understanding of isotopes and their relationship to the line of stability through an engaging hands-on group activity that they won’t soon forget.

Included in each kit:

  • Chart of the Nuclides: 8′ x 4′ vinyl banner
  • Extended Periodic Table: 6′ x 2′ vinyl banner
  • Element Tiles: an assortment of 389 laminate 2’ x 2′ green, blue, red, white, and blank tiles
  • Class plan and easy instructions

Crafted of high-quality materials, the Isotope Discovery Kit can be used again and again for years to come, making the purchase a lasting value.

$589.95 each ($530.96 for American Nuclear Society members). To order item #750078 please visit the ANS Store.

ISOTOPE DISCOVERY KIT

Here is a quick demonstration of the latest ANS teacher resource – the Isotope Discovery Kit

Top 10 Things You Love (But Didn’t Know) About Nuclear Technology

Grade Level: 5-12

Nuclear science and technology improves our lives in many ways.  From reliable energy, to improved health care and national security, the Top 10 Things You Love (But Didn’t Know) About Nuclear Technology will help you teach your students how various applications of nuclear technology are used in every day life.

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Full-color, 2-page brochure. 8 1/2″ x 11″.

$.25 each ($.23 for American Nuclear Society members). To order item #750092 please visit the ANS Store.

From Harvest to Home

Grade Level: 5-12

From Harvest to Home describes how radiation technology is used to improve the food we eat. This flyer will help your students understand how radiation benefits the food production cycle and helps the environment. It is also available in Arabic.

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Full-color, 2-page brochure. 8 1/2″ x 11″.

$.29 each ($.26 for American Nuclear Society members). To order in English or Arabic, please visit the ANS Store.

 

Anatomy of an Atom

Grade Level: All (K-12)

The Anatomy of an Atom die cut mobile is a fantastic activity that makes creating a three-dimensional atom fun and easy. Great for classroom lessons, Science Fairs, or Girl Scout and Boy Scout projects.

Only $1 each ($.90 for American Nuclear Society members). To order Item #750090, please visit the ANS Store.

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Sustainable Solutions for Our World

The Sustainable Solutions for Our World brochure describes how nuclear science and technology (NS&T) are crucial to sustainable development, and addressing  the concerns from the Rio+20 conference. It also discusses the contributions of NS&T to improved health, improved quality of life, and increased capacity for economic development.

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Full color, 8-page brochure.  8 1/2″ x 11″.

This brochure can be purchased for $.75 each ($.68 for American Nuclear Society members). To order Item #750077, please visit the ANS Store.

Medical Use of Radioisotopes

Grade Level: 5-12

The Medical Use of Radioisotopes brochure describes the amazing applications of radiation and radioisotopes in the medical field. From sterilization of products, new drug testing, imaging, and therapy the medical applications of nuclear science and technology improves our health and quality of life. It also addresses the current Molybdenum-99 shortage and the importance of this isotope.

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Full color, 8-page brochure.  8 1/2″ x 11″.

This brochure can be purchased for $.75 each ($.68 for American Nuclear Society members). To order Item #750089, please visit the ANS Store.


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