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Light Stick Chemistry

Grades: 5-8
Author: Tess Ewart


Abstract

Module Description

As a result of this presenter-conducted module, participants will use hands-on activities to define chemiluminescence and bioluminescence. Participants will determine the effect of temperature on reactions. Safety considerations for lab activities will be discussed. Participants will design a lesson that uses inquiry to use in their classroom.


Objectives

  • Participants will define chemiluminescence and bioluminescence.
  • Participants will observe the effect of temperature on reactions.
  • Participants will design and implement in their classrooms a lesson that uses inquiry.

Materials

Three chemiluminescent sticks (also called "cool light sticks")

Thermometer or temperature sensor

Beakers (large enough to submerge one stick)

Ice water

Warm water

Room-temperature water

Timer

Room that can be darkened

Digital camera (optional)

NOTE: Cool light sticks are available at many toy stores, marine supply stores, party goods stores, and stores offering camping and fishing supplies.


Procedures

**This professional development module is based on the Ohio Resource Center lesson #2361 and therefore contains the lesson plan as found on the ORC web site. The module writer acknowledges the scholarly work of the lesson plan author and does not claim any connection to the writing of the lesson plan. **

Engagement

Show a picture of an animal that shows bioluminescence such as the jellyfish image found at http://www.biolum.org/marine/biolum2/middle/livinglights/lljelly2content.html . Have the participants try to identify what they see with the reasons for their ideas.

Assessment: Participants' discussion.

Exploration

Ask the participants to come up with safety considerations for the materials to be used during experimentation. Discuss as a group these safety considerations. See Safety/Disposal section for safety precautions.

Have the participants write down their predictions for the effect temperature will have on the light sticks.

Have the participants work in groups (the number of lab set ups may determine the number of people in the group) following these procedures:

  1. Fill one beaker with ice water. Fill another with room temperature water. Fill a third one with warm water.
  2. Insert a light stick into each of the water-filled beakers, but do not activate it. Try to immerse as much of the stick in the water bath as possible. NOTE: You may have to tie a small weight onto the stick to insure that it does not float to the surface.
  3. Wait several minutes. Then use a thermometer to measure the temperature of the water in each of the three beakers. Record these values.
  4. Activate all three light sticks.
  5. Turn off the room lights. Compare and contrast the brightness of the generated light. Which beaker contains the brightest stick? Which beaker contains the dimmest stick? Record you observations.
  6. If you have a digital camera, use it to capture a record of the light generated by these side-by-side tubes. Make sure that all three glowing sticks are included in the same single image. Once the image is taken, you can return the room lights to their normal level.
  7. At 15-minute intervals, dim the room lights. Use the digital camera to capture additional images of the three glowing light sticks.
  8. Continue comparing and contrasting the relative brightness of the three sticks. If applicable, note the time at which each stick no longer appears to glow.

Assessment: Participant's activity results.

Explanation

Ask the participants the following questions:

  1. In step 2, why was it necessary to place the light sticks in the water filled beakers for several minutes before performing the activity?

(During this time the temperature of the light stick chemicals changed to reflect the temperature of the surrounding water.)

  1. In step 6, why was it necessary to include all three sticks in the same image?

(This way you could compare the relative brightness of the sticks).

  1. In which beaker did the stick glow brightest?

(warm water)

  1. In which beaker did the stick glow dimmest?

(ice water)

  1. In which beaker did the glow last longest?

(ice water)

  1. In which beaker did the glow go away the quickest?

(warm water)

  1. Is the brightness of the glow related to the time that this effect lasts? Explain.

(Yes. The brightest glow (warm water) lasts the shortest time. Likewise, the dimmest glow (ice water) lasts the longest.)

  1. The rate of a reaction is dependent upon several factors, including the temperature of the reaction vessel. How can this concept be applied to your observations?

(Warm water beaker: At a higher temperature, the reaction proceeded at a faster rate. This produced a brighter glow. Since the reactants were used up quicker, the glow ended sooner. Cold water beaker: In contrast, the cooled stick contained a slower reaction. This produced a reduced glow that lasted a longer period.)

Assessment: Participants' discussion.

Elaboration

Have participants discuss ways that they could use inquiry in their classroom settings.

  • Participants should complete a lesson plan template for a lesson that addresses grade level content indicators and involves inquiry for use in their classroom. See Lesson Plan Template handout.
  • Further and on-going collaboration among participants should be encouraged.

Rationale

From http://uakron.edu/cpspe/agpa-k12outreach/best-teaching-practices/

Inquiry is the most abstract yet most scientific of all of the best practices in science. Inquiry is a method of approaching problems that is used by professional scientists but is helpful to anyone who scientifically addresses matters encountered in everyday life. Inquiry is based on the formation of hypotheses and theories and on the collection of relevant evidence. There is no set order to the steps involved in inquiry, but children need to use logic to devise their research questions, analyze their data, and make predictions. When using the inquiry methods of investigation, children learn that authorities can be wrong and that any question is reasonable.

The most abstract component of inquiry is imagination. Both students and professional scientists have to be able to look at scientific information and data in a creative way. This unconventional vision allows them to see patterns that might not otherwise be obvious.

Teachers can incorporate inquiry approaches to learning, for example, by allowing small groups of students to explore a particular natural phenomenon that might exhibit certain trends or patterns.


Science Standards

NSES CONTENT STANDARD A: As a result of activities in grades 5-8, all students should develop an understanding of the following Science as Inquiry topics:

  • Design and conduct a scientific investigation.
  • Use appropriate tools and techniques to gather, analyze, and interpret data.

NSES CONTENT STANDARD B: As a result of their activities in grades 5-8, all students should develop an understanding of the following Physical Science - Properties and Changes of Properties in Matter topics and Transfer of Energy topics:

  • Substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties. In chemical reactions, the total mass is conserved. Substances often are placed in categories or groups if they react in similar ways; metals is an example of such a group.
  • Energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical. Energy is transferred in many ways.

NSES CONTENT STANDARD C: As a result of their activities in grades 5-8, all students should develop an understanding of the following Life Science Structure and Function in Living Organisms topics:

  • Specialized cells perform specialized functions in multicellular organisms.

NSES PROFESSIONAL DEVELOPMENT STANDARD A: Professional development for teachers of science requires learning essential science content through the perspectives and methods of inquiry. Science learning experiences for teachers must:

  • Involve teachers in actively investigating phenomena that can be studied scientifically, interpreting results, and making sense of findings consistent with currently accepted scientific understanding.
  • Address issues, events, problems, or topics significant in science and of interest to participants.
  • Introduce teachers to scientific literature, media, and technological resources that expand their science knowledge and their ability to access further knowledge.
  • Build on the teacher's current science understanding, ability, and attitudes.
  • Incorporate ongoing reflection on the process and outcomes of understanding science through inquiry.
  • Encourage and support teachers in efforts to collaborate.

NSES PROFESSIONAL DEVELOPMENT STANDARD B: Professional development for teachers of science requires integrating knowledge of science, learning, pedagogy, and students; it also requires applying that knowledge to science teaching. Learning experiences for teachers of science must:

  • Connect and integrate all pertinent aspects of science and science education.

Best Teaching Practices

  • Inquiry Approaches

Time Frame

1-2 hours.


Preparation

Notify the participants in advance to bring their curriculum guide/map or textbook to facilitate their development of an implementation plan.

Make sure the room in which the presentation will be held can be darkened.


Safety

Safety considerations:

  • Any glassware that breaks during the activities should be swept up using a broom and dust pan. Never pick up broken glass with your hands! The broken glassware should be discarded in a specially marked receptacle.
  • Strong consideration should be given to using open flame with students. Be sure to use tongs or mitts when handling glassware that has been heated. Aprons and goggles should be worn when heating materials in glassware. Long hair should be tied back; long pants and closed toe shoes should be worn. Long sleeves should be rolled up or pushed back.
  • Make sure the water that is used for the “warm water” beaker is not boiling. This could melt the plastic on the outside of the light stick.
  • An alternative to using alcohol thermometers that are made of glass in lab activities would be to use temperature probes or sensors.
  • Participants should be cautioned before task and instructed to wash their hands after completing the task.
  • Be careful!
  • Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science investigations.

For disposal of the light sticks, follow the manufacturer's instructions. Light sticks are usually discarded with ordinary trash.


Assessment

Assessments can be found at the end of each learning cycle stage. For an overall assessment, have the students investigate the role of bioluminescence in Naval operations or explain the role of bioluminescence in different animals lives.


Explanation of Science

From the Ohio Resource Center Lesson #2361:

Sunlight that penetrates the ocean is absorbed as it passes through the surface layers of the water. Since solar radiation does not reach the ocean depths, the bottom of the deep ocean remains largely in complete darkness. However, certain animals in this extreme environment can generate light to communicate with each other, and even to lure prey, thanks to a process known as bioluminescence.

Bioluminescence is a form of chemiluminescence - the production of light through chemical means. In contrast to light generated by high temperatures, which allows objects to get hot (such as light bulbs, stars, or fireplace pokers), this "cool" process relies on chemical reactions. When chemicals combine, they release the energy that has been stored in their chemical bonds. In chemiluminescent reactions, this stored energy is released as light. In most bioluminescent deep sea animals, two basic chemicals - luciferin and luciferase-combine to produce light as a by-product of the reaction.

You may also have seen chemiluminescent sticks, bracelets, or other items that depend upon chemical reactions to produce light. If you examine these items closely, you will find that they consist of a sealed vial immersed within another liquid. When the inner vial is crushed, its contents mix with the surrounding fluid. As the chemicals combine, they generate visible light. In this activity, you will explore how the temperature of the chemicals that combine effects a chemiluminescent reaction.


Handouts

Light Stick Data Sheet


Extensions

Extensions from the Ohio Resource Center Lesson #2361:

Glowing Artwork:

Some animals have light organs that are concentrated around the eyes. Other organisms have strands of light spots that extend their whole body length.

Check out these sites: www.bio.davidson.edu/Courses/anphys/1999/Cody/fish.html, http://www.lifesci.ucsb.edu/~biolum/organism/photo.html, http://www.hboi.edu/gallery/photoarchive/bio_gallery_1.html, to learn more about the placement patterns of light organs in fish, cephalopods, jellyfish and other organisms.

For this activity, you'll need both a set of standard watercolor paints and a small vial of glow-in-the-dark paint. You can obtain all of these non-toxic paints from a local art store or an Internet outlet. Use the standard paints to produce images of various deep-sea fish and invertebrates. Then, use the glowing paint to add a pattern of glowing spots to each drawing. Challenge students to identify the painted subjects by only the glowing patterns that are revealed in dimmed lighting.


Lesson Implementation Template

Download Lesson Implementation Template: Word Document or PDF File


Equity

Issues to consider are the following: seating so everyone can see the display, make sure every person participates in discussions, and grouping with diversity in mind.


Resources

None available for this module.


References

http://www.ohiorc.org/

http://www.biolum.org/marine/biolum2/middle/livinglights/lljellycontent.html