Archive for June, 2014:

Making Atoms Visible : Autoradiographs

Description: With the Autoradiograph activity, students gain a better understanding of the different types of radiation, alpha, beta, and gamma. This is a way that students can detect invisible emissions.

This experiment is best used by students working in groups.

autoradiographs

Grade Level
1-5 (sun paper)
6-8 (demonstration)
9-12 (activity)

Disciplinary Core Ideas (DCI, NGSS)
5-PS1-1, MS-PS1-1, MS-PS1-4, HS-PS1-8, HS-PS4-2, HSPS4-5

Time for Teacher Preparation
30-60 minutes – To gather materials and set-up
1 Week to develop the autoradiograph

Activity Time:
30-60 minutes (1 Class Period) for set-up
30-60 minutes (1 Class Period) to develop the autoradiograph

Materials

  • Pen, Marker, or Pencil
  • 1 box-Polaroid Type 57 instant (3000 speed) 4×5 packet film
  • Radiation Sources:
    • 1 Coleman Lantern Mantle
    • Fiesta®ware plate
    • Radium-dial clock
    • Smoke-detector part (Americium)
    • Uranium ore (sealed in a plastic ziplock to prevent dust contamination)
  • Rubber or plexiglass photo developing roller, rolling pin, or sturdy wooden or plastic ruler
  • Sheet of aluminum foil, paper (optional)
  • Student Data Collection Sheets

Safety

  • Students should use care when handling aluminum foil
  • Students should not touch chemicals on polaroid film on their bare hands
  • Students should use care when touching radioactive materials.
  • Students should wash hands after handling radioactive materials.

Science and Engineering Practices (NGSS)

  • Ask questions and define problems
  • Use Models
  • Plan and Carry out investigation
  • Analyze and interpret data
  • Using mathematics, information and computers
  • Argue from Evidence
  • Obtain, evaluate and communicate information

Cross Cutting Concepts (NGSS)

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

Objectives

  • To visually demonstrate the concepts of ionizing radiation.

Background

Often used to detect radiation by imaging its emissions, an autoradiograph is a representation of where radioactive substances are located. The image can be projected onto a medium such as an x-ray film, nuclear emulsion, or even photographic film. Autoradiography, which can also be digital, is used in many cases for biological and medical applications. In contrast to other methods of detecting radiation, they can show the locations of radioactive materials in a sample. The images can therefore be used with biological specimens labeled with such materials, to track cellular activity for example.

In its basic form, an autoradiograph can require film to be exposed overnight. Radioactivity is detected through bands on an image, which are produced as particles hit crystals of silver halide. The images on the film typically depend on the activation of the crystals and the effects of particles on a gel. If each crystal is insulated by a gelatin capsule, then a permanently developed image can accurately show the sample and where it is radioactive.

An autoradiograph is often taken after biological tissue is exposed to a radioactive substance, left for a certain period of time, and examined under a microscope. Sections can be cut and a photographic image can be developed as a radioisotope decays. Samples are often stained to enhance the detail and to see the grains of silver that react with the substance. The resulting autoradiograph can be recorded and kept on file as part of an experiment or test.

While a solid film was typically used in the past, a liquid emulsion is often used in the 21st century to make an autoradiograph. This technique can take less time to complete. Liquid can flow and make the thickness of the sample uneven, but following the basic steps for coating slides and developing the film can dry the sample appropriately. A phosphor-imager screen can help detect radioactivity in gel quicker than x-ray film. It is typically used with electronic instruments and a computer system that can digitally image the sample.

Autoradiographs can show radioactive particles attached to enzymes or integrated into nucleic acid. Metabolic processes can be tracked in cells when images of radioactive particles are compared. Researchers can track proteins, photosynthesis, and the division and movement of cells. Sequences of deoxyribonucleic acid (DNA) can be tracked. Autoradiography DNA is often used to monitor cell cycles and track the progress of viruses to analyze their behavior.


Teacher Lesson Plan:

Traditional
Paper

  1. Prepare Autoradiographs in accordance with Autoradiograph instructions:
    1. Place a key, coin, or other metal object onto the face of the film sheet. Place a Coleman lantern mantle, Fiesta®ware plate, or a radium-dial clock completely over the object. Let it sit for at least one week.
    2. Remove the mantle and object from the film sheet. Lay the sheet on a flat table with the side marked “This side toward lens” up. Locate the bulge in the sheet that contains the developer chemicals. Place a ruler, flashlight, or other stiff, heavy object (a roller works best) behind the bulge and, while applying moderate pressure, slowly and evenly drag the object across the film sheet to spread the chemicals. Even distribution of the chemicals is critical for good development. It takes lots of practice to make a good picture.
    3. Wait 30 seconds for the film to develop then open the packet.
    4. Students will find a dark shadow of the metal object surrounded by a white “fog”. The white is due to the radiation given off by the Coleman mantle exposing the film. The dark shadow is because the metal object shielded the radiation from the film.

NOTE: You can use the three radiation sources on one film sheet in lieu of the key and Coleman lantern mantle, Fiesta®ware plate, or a radium-dial clock. Students will find that only the beta and gamma sources will expose the film. This is because the paper surrounding the film shields alpha radiation.
NOTE: Elementary school students could try to perform this experiment using SunSensitive paper rather than Polaroid film. The SunSensitive paper reacts to UV sunlight and would be a good substitution for Polaroid film for this experiment.

NGSS Guided Inquiry

  1. Break students up into groups of three
  2. Give each group:
  • A sheet of film
  • A sheet of paper and some aluminum foil
  • An alpha, beta, and gamma source
  1. Have groups design an experiment to discover what kind of radiation each source is emitting.

Student Procedure

  1. Place a key, coin, or other metal object onto the face of the film sheet. Place a Coleman lantern mantle, Fiesta®ware
    plate, or a radium-dial clock completely over the object
  2. Allow the photos to develop for a week
  3. Develop the film according to your teacher’s instructions
  4. Observe the resulting image that is developed

Data Collection
Student Data Collection Sheets
Students should label sources and type of radiation on film

Post Discussion/Effective Teaching Strategies
Questions provided on the Student Data Collection Sheets

Questions

  1. What caused the image to develop on the sheet of film?
  2. How did you use shielding principles to identify what kind of radiation each source emits?
  3. For sun paper activity, how does placing an object on the sun paper and putting sun screen on skin compare to protecting an area from the sun’s radiation?

 

Assessment Ideas
Have students identify an unknown source by experimenting with shielding, different sources, and different types of film.

Differentiated Learning/Enrichment

  • Explore how autoradiography is used in DNA sequencing.
  • Have students place various objects between the film and the source (coin, leaf, paperclips, etc.)

Enrichment Question

  1. How did scientists use this concept in medicine?
  • Compare the early usage of 1900’s Medicine to today’s application.

Half-Life : Paper, M&M’s, Pennies, or Puzzle Pieces

Description: With the Half-Life Laboratory, students gain a better understanding of radioactive dating and half-lives. Students are able to visualize and model what is meant by the half-life of a reaction. By extension, this experiment is a useful analogy to radioactive decay and carbon dating. Students use M&M’s (or pennies and puzzle pieces) to demonstrate the idea of radioactive decay. This experiment is best used by student working in pairs.

mm

Grade Level:
5-12 grade

Disciplinary Core Ideas (DCI)
3-5ETS1-2, MS-ESS1-4, HS-ESS1-6

Time for Teacher Preparation
40-60 minutes – To gather materials

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

Materials:

  • Bag of: M&M’s ®, pennies or, puzzle pieces
  • Paper – 8.5˝ x 11˝
  • Graph Paper
  • Zip-Lock Bags
  • Pen, Marker, or Pencil
  • Student Data Collection Sheets

Safety

  • Students should not eat M&M’s®, Pennies, or Puzzle Pieces

Science and Engineering Practices

  • Ask questions and define problems
  • Use models
  • 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
  • Systems and System Models
  • Energy and Matter: Flows, Cycles, and Conservation

Objectives
Students try to model radioactive decay by using the scientific thought process of creating a hypothesis, then testing it through inference. 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 the process of graphing the data.

Students should begin to see the pattern that each time they “take a half-life,” about half of the surrogate radioactive material becomes stable. Students then should be able to see the connection between the M&M’s and Puzzle Pieces and radioactive elements in archaeological samples. Seeing this connection will help students to understand how scientists can determine the age of a sample by looking at the amount of radioactive material in the sample.

  • To define the terms half-life and radioactive decay
  • To model the rate of radioactive decay
  • To create line graphs from collected data
  • To compare data
  • To understand how radioactive decay is used to date archaeological artifacts

Background
Half-Life
If two nuclei have different masses, but the same atomic number, those nuclei are considered to be isotopes. Isotopes have the same chemical properties, but different physical properties. An example of isotopes is carbon, which has three main isotopes, carbon-12, carbon-13 and carbon-14. All three isotopes have the same atomic number of 6, but have different numbers of neutrons. Carbon-14 has 2 more neutrons than carbon-12 and 1 more than carbon-13, both of which are stable. Carbon-14 is radioactive and undergoes radioactive decay.

Radioactive materials contain some nuclei that are stable and other nuclei that are unstable. Not all of the atoms of a radioactive isotope (radioisotope) decay at the same time. Rather, the atoms decay at a rate that is characteristic to the isotope. The rate of decay is a fixed rate called a half-life.

The half-life of a radioactive isotope refers to the amount of time required for half of a quantity of a radioactive isotope to decay. Carbon-14 has a half-life of 5730 years, which means that if you take one gram of carbon-14, half of it will decay in 5730 years. Different isotopes have different half-lives.

The ratio of the amounts of carbon-12 to carbon-14 in a human is the same as in every other living thing. After death, the carbon-14 decays and is not replaced. The carbon-14 decays, with its half-life of 5,730 years, while the amount of carbon-12 remains constant in the sample. By looking at the ratio of carbon-12 to carbon-14 in the sample and comparing it to the ratio in a living organism, it is possible to determine the age of a formerly living thing. Radiocarbon dates do not tell archaeologists exactly how old an artifact is, but they can date the sample within a few hundred years of the age.


Teacher Lesson Plan:

M&M’s® (or Pennies or Puzzle Pieces)

  1. Give each student 10 M&M’s® candies of any color and a zip lock bag. All of M&M’s® candies are considered radioactive.
  2. Have the student put the M&M’s® into the zip lock bag and shake the bag. Have the students spill out the candies onto a flat surface.
  3. Instruct the students to pick up ONLY the candies with the “m” showing – these are still radioactive. The students should count the “m” candies as they return them to the bag.
  4. Have the students record the number of candies they returned to the bag under the next Trial.
  5. The students should move the candies that are blank on the top to the side – these have now decayed to a stable state.
  6. The students should repeat steps 2 through 5 until all the candies have decayed or until they have completed Trial 7.
  7. Set up a place on the board where all students or groups can record their data.
  8. The students will record the results for 9 other groups in their data tables and total all the Trials for the 100 candies

NGSS Guided Inquiry
Explain about radiation and half-lives of isotopes. Tell students to design their own experiment, using paper, M&M’s®, Pennies, other 2 sided material or Licorice as a radioactive material undergoing decay to discover the nature of the half-life of that material.

You might suggest that the students experiment with their graphing results to see if trends begin to form.


Student Procedure

M&M’s® (or pennies or puzzle pieces)

  1. Put 10 M&M’s® candies of any color into a zip lock bag. Each group is starting with 10 M&M’s® candies, which is recorded as Trial 0 in the data table. All of the M&M’s® candies are considered to be radioactive at the beginning.
  2. Shake the bag and spill out the candies onto a flat surface.
  3. Pick up ONLY the candies with the “m” showing – these are still radioactive. Count the “m” candies as you return them to the bag.
  4. Record the number of candies you returned to the bag under the next Trial.
  5. Move the candies that are blank on the top to the side – these have now decayed to a stable state.
  6. Repeat steps 2 through 5 until all the candies have decayed or until you have completed Trial 7.
  7. Record the results for 9 other groups and total all the Trials for the 100 candies.

Data Collection
Student Data Collection Sheets

Post Discussion/Effective Teaching Strategies
Questions provided on the Student Data Collection Sheets

Questions

M&M’s® (or Pennies or Puzzle Pieces)

  1. Define the term half-life.
  2. What does it mean when we say an atom has “decayed”?
  3. Do the number of atoms you start with affect the outcome? Explain.
  4. Did each group get the same results?
  5. Did any group still have candies remaining after Trial 7?
  6. Why do the totals for the 10 groups better show what happens during half-life rather than any other group’s results?
  7. What happens to the total number of candies with each trial (half-life)?
  8. Plot the total results on a graph with number of candies on the vertical axis and trial number on the horizontal axis. Is the result a straight or a curved line? What does the line indicate about the nature of decay of radionuclides?
  9. How do scientists use radioactive decay to date fossils and artifacts?

Assessment Ideas

  • Question the student about how this experiment is similar to Carbon Dating.

 

Differentiated Learning/Enrichment

  • Have the students calculate the age of objects when given the half-life, original amount, and current amount of that material.

 

Enrichment Question

  1. The population of the earth is doubling every 40 years. If the population of the earth is now 7 billion people, how many people will be here when you are 95 years old?

Fission Demonstration

Description:With the Fission Demonstration, students gain a better understanding of nuclear fission and fusion. Students are able to visualize and model what is meant by nuclear fission. By extension, this experiment is a useful analogy to the generation of electricity via nuclear reactors. This experiment is best performed by students working in groups.

fissionballoons

Grade Level:
5-10

Disciplinary Core Ideas (DCI, NGSS)
5-PS1-1, 5-PS1-3, 5-ESS3-1, 3-5 ETS1-1, MS-PS1-4, MSPS1-5, MS-PS3-1, MS-PS3-2, MS-PS3-4, MS-PS3-5, HSPS1-1, HS-PS1-8

Time for Teacher Preparation
30-60 minutes – To gather materials and set-up

Activity Time:
30-60 minutes (1 Class Period)

Materials

Safety

  • Student should use care when handling scissors

Science and Engineering Practices (NGSS)

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

Cross Cutting Concepts (NGSS)

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

Objective
Learn the concepts of nuclear fission and fusion and investigate how these reactions are used to generate energy.


 

Background
Fission is the release of energy by splitting heavy nuclei such as uranium-235 and plutonium-239. Each fission releases 2 or 3 neutrons. These neutrons are slowed down with a moderator, so they can initiate more fission events. Control rods absorb neutrons to keep the chain reaction in check. These fast-moving fission fragments are knocked into a water molecule, which causes the water molecules to move a little bit faster. This increased amount of motion is measured as an increase in temperature. The energy from the reaction drives a steam cycle to produce electricity. Nuclear power produces no greenhouse gas emissions; each year U.S. nuclear plants prevent atmospheric emissions totaling:

  • 5.1 million tons of sulfur dioxide
  • 2.4 million tons of nitrogen oxide
  • 164 million tons of carbon

Fusion is the opposite of fission. Fusion is the release of energy by combining two light nuclei such as deuterium and tritium.
The goal of fusion research is to confine fusion ions at high enough temperatures and pressures, and for a long enough time,
to fuse. There are two main confinement approaches:

  • Magnetic confinement uses strong magnetic fields to confine the plasma.
  • Inertial confinement uses powerful lasers or ion beams to compress a pellet of fusion fuel to the right temperatures and pressures.

 

Teacher Lesson Plan:

Traditional
This experiment can be performed as either a demonstration or by the students themselves. Regardless, the procedure remains
the same. Explain that the balloon is like a heavy nucleus, such as uranium-235 or plutonium-239. Once they have twisted the
balloon into two sections, cut the twisted section to cause the “nuclei” to undergo fission. When the two smaller balloons are released, explain that the balloons flying off represent the energy given off by the reaction and how these fragments knock
water molecules, speeding them up, and thus increasing their temperature. Afterwards, collect the balloon fragments to throw
away and explain that nuclear waste needs to be disposed of properly and not dumped into the environment (just as you would
not leave pieces of balloons lying around the classroom).

NGSS Guided Inquiry
Split students into small groups and give each group a balloon. Have students design an experiment to model nuclear fission
with the balloon acting as a heavy nucleus, such as uranium-235 or plutonium-239. Have each group discuss ways to dispose of
the waste products.

Student Procedure

The students should draw the results that they observe onto the Student Data Collection Sheet that are provided.

  1. Blow up the twisting balloon and tie off the end.
  2. Twist the balloon in the center, creating two separate, but equal sections.
  3. While holding both ends of each inflated section, have a partner cut the twisted portion of the balloon in the middle.
  4. Hold onto the ends of both of the resulting smaller balloons.
  5. Release the balloons allowing them to fly off.
  6. Collect the balloon fragments to throw away.

Data Collection
Student Data Collection Sheets
Post Discussion/Effective Teaching Strategies


Questions

  1. How was this activity similar to nuclear fission?
  2. What would need to happen to model nuclear fusion?
  3. Why is it important to dispose of radioactive waste properly?

 

Assessment Ideas

  • Question the student as to the similarities and differences of nuclear fission and fusion.

 

Differentiated Learning/Enrichment

  • Have students model fusion
  • Have students research contamination by waste products of fission.

 

Enrichment Questions

  • How could fission be used to generate electricity in a nuclear power plant?
  • Instead of scissors, what is actually used to make an atom undergo fission?

 

Further Resources

Applications: Electricity
Nuclear Fission

Nuclear Fission Animation

Citations for Reference
Adapted from Easy to Perform Classroom Experiments in Nuclear Science. (1992), BROMM, B, American Nuclear Society.

Energy Production : Critical Mass

Description:

With the Critical Mass Demonstration, students gain a better understanding of critical mass and how a chain reaction can become uncontrolled. Students are able to visualize what is meant by subcritical, critical, and supercritical mass. By extension, this experiment is a useful analogy to nuclear fission. This experiment is best used by students working in groups.

chainreactions

Grade Level:
5-12

DCI:

5-ESS3-1, 3-5 ETS1-1, 3-5ETS1-2, MS-PS1-4,  MS-PS3-4, MS-ESS3-1, MS-ESS3-3, MS-ESS3-4, MS-ESS3-5, MS-ETS1-1, MS-ETS1-2, MS-ETS1-3, MS-ETS1-4, HS-PS1-1, HS-PS1-8, HS-PS3-3, HS-PS3-4, HS-ESS2-4, HS-ESS2-6, HS-ESS3-2, HS-ESS3-3, HS-ESS3-4, HS-ESS3-6

Time for Teacher Preparation: 30-60 minutes – To gather materials and set-up

Activity Time: 30-60 Minutes (1 Class Period)

Materials:

  • Pen, Marker, or Pencil
  • Student Data Collection Sheets
  • 1 Stopwatch per group of students
  • Light weight balls, ping pong balls, marshmallows, etc. (# of students * 2)
    • Alternatively, the activity can be demonstrated with mousetraps

Safety:

  • It is important that students throw their balls straight up into the air and not aim directly for their fellow students.

Science and Engineering Practices:

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

Cross Cutting Concepts:

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

Objectives:

  • Learn the concept of critical mass and how a chain reaction can become uncontrolled
  • Define Critical Mass

Background:

The splitting of a massive nucleus into two fragments, each with a smaller mass than the original, is known as nuclear fission. A typical example of nuclear fission is the splitting of a uranium-235 nucleus. This is a reaction that is used in nuclear reactors to generate heat by which steam is produced and used to turn turbines that generate electricity. The fission of uranium-235 begins when the uranium-235 nucleus captures a slow moving neutron and forms an unstable “compound nucleus”. The compound nucleus quickly disintegrates into two smaller nuclei, such as barium-141 and krypton-92, two or three neutrons (2.5 average), and a tremendous amount of energy (~200MeV per fission).

Because the uranium-235 fission reaction produces 2 or 3 neutrons, it is possible for those neutrons to initiate a series of subsequent fission reactions. Each neutron released can initiate another fission event, resulting in the emission of more neutrons, followed by more fission events, and so on. This is a chain reaction – one event triggers several others, which in turn trigger more events, and so on. In a nuclear power plant the chain reaction is controlled by restricting the number of neutrons available to collide with the uranium. This is accomplished by absorbing some of the released neutrons with various materials. In an uncontrolled chain reaction (such as an atom bomb explosion) there is nothing to control the number of neutrons being released, so the rate of the chain reaction increases dramatically.

There are two parameters needed to create a critical mass, the number of atoms and the spacing of the atoms. In this demonstration each student represents a uranium atom inside of a nuclear reactor. Each uranium atom releases two neutrons when it fissions.  For this demonstration, the larger the number of student participants, the better the results.


Teacher Lesson Plan:

Traditional

Arrange the students in a square array approximately 3 feet apart and give each student two balls. Take a ball for yourself and to begin the activity, throw your ball up into the air or at a student. Any student that is hit with this ball throws their two balls straight up into the air. Any student hit by these balls then throws their balls into the air. The reaction continues until there are no more balls in the air. The first time, the reaction will probably die out quickly, this is called subcritical.

Repeat the process, but place the students only 1 foot apart this time and carry out the activity. This time, the reaction should be self-sustaining. This is called critical and a critical reactor is running at a steady state.

Repeat the process a final time, but place the students in a tight array without any space between them. This time, there should be lots of balls in the air at one time. This represents a supercritical mass, or when a reactor is increasing its power level.

Variation

Replace the students with mousetraps and place them in an array.  Set the traps and place a ping pong ball on each one.  Be careful not to get your fingers caught in the traps, as sometimes they will go off when you set the ball on them. Then drop a ball on the array and watch the ball bounce around, setting off more traps.  View demo here.

Optional Exercise:

In a nuclear reactor, the reaction is controlled by control rods. These are special rods that go in between groups of fuel rods (which have fuel pellets stacked in them) inside the reactor. The control rods help to start (when they are removed), stop (when they are fully inserted), increase or decrease (when they are partially removed or inserted) the fission process.

Explain that students will now demonstrate a controlled reaction. Use the same students to be atoms or select a new group. Choose one (or more) additional student(s) to be a control rod. Their job is to stand inside the “atoms” group and try to grab or bat away the falling balloons before they hit a student. Since there are now control rods in your demonstration, the first balloon may have to be thrown several times before it hits a student. After all the balloons are thrown, discuss what happened. Fewer students should have been hit because the control rods intercepted some of the “neutrons.” Students can see how the rods slow down and can even stop a chain reaction. When that happens, the fission process will stop very quickly.

NGSS Guided Inquiry:

Split students into small groups and give each student two balls. Have students design an experiment to model nuclear fission and critical mass with the balls acting as neutrons in a reactor.


Student Procedure

Hold a ball in each hand.

If you are hit by a ball, throw your balls straight up into the air without aiming directly at your fellow students.

Time and record how long each reaction lasts, which is when the last ball is thrown in the air.

Post Discussion/Effective Teaching Strategies

Answer the following questions provided by your teacher.

Questions:

  1. What happened during each trial and why?

Assessment Ideas

  • Have students discuss the differences between subcritical, critical, and supercritical masses.
  • Have students discuss how the different arrangements of students affect the reactor reaching subcritical, critical, and supercritical masses.

Differentiated Learning/ Enrichment

Enrichment Question

  1. How do you think nuclear power plant operators use this concept to power up or power down?

Further Resources:

 

Nuclear Technology in Industry – Everyday Applications

sodacans

Background:
Atoms that emit radiation are called radioisotopes. There are radioisotopes of most of the chemical elements on earth. Some occur naturally; many more can be made, for example, in a reactor. Radioisotopes and radiation have many uses in our daily lives.

Materials:

  • Flashlight
  • six sheets of 8 ½ ” x11″ paper
  • a clear glass jar or bottle
  • milk or colored liquid to fill the bottle or jar

Conduct the following simple activities to illustrate some industrial applications of nuclear technology. Students can be assigned to active roles – holding the flashlight, holding the paper, etc.


 

Activity 1. No more empties.

Objective:
This fill gauge demonstration shows how radioactive isotopes can be used to measure the fill level of containers such as soft drink cans.

Procedure:
Place the empty jar or bottle on a table. Shine the light through it with the flashlight. Hold a sheet of paper near the opposite side of the bottle. Fill the bottle with the liquid and observe the light coming through onto the paper.

Can you tell the height of the liquid in the bottle?

The light shines through the bottle onto the paper only above the level of the liquid. Radioactive emissions penetrating an almost-filled container of liquid could be used to operate an automatic shut-off valve, setting it so that the shut-off valve would be activated when the radioactive emissions no longer penetrate the tank or container- the container is filled.


Activity 2. How thick is it?

Objective:
In this demonstration, the flashlight represents a radioactive isotope giving off radiation that would be used to gauge thickness of metal, plastic or paper being produced in a plant. When the capability of penetration of the radioactive emission is known, the amount of radioactive emissions (the light in the demonstration) that penetrates the material indicates the thickness of the material.

Procedure:
Lay the flashlight on a table (or ask a student to hold it). Darken the room; turn on flashlight. Hold a sheet of paper in front of the light about a foot away from the beam.

How much light goes through?
Add a second sheet of paper and observe the change in amount of light. Keep adding sheets until no light goes through. (Note that this activity also demonstrates shielding.


Know Nuclear

  • Sign up for newsletters
  • Center for Nuclear Science and Technology Information of the American Nuclear Society

    © Copyright 2018