Program Organization

Facilities

Adequate facilities and materials, by themselves, do not create a safe chemistry class. But they contribute greatly to the ability of a teacher to deliver an activity-based course. Proper use of the facilities and materials is also critical.

Since the use of a wide range of instructional methods in Chemistry 20/30 is desirable, more flexible teaching areas are useful. This might be a well designed laboratory which can be reconfigured to accommodate small group discussions, small group and large group laboratory activities, lectures, research work or other activities. Or, it may be a combination of two or more existing rooms.

Some features of a good science laboratory/facility are:

• two exits, remote from each other
• master shut-off controls for the water, natural gas, and electrical systems. These should be easily accessible and easy to operate
• a spacious activity area where students can work without being crowded or jostled
• safety equipment which is visible and accessible to all
• a ventilation system which maintains negative pressure in the lab
• enough electrical outlets to make the use of extension cords unnecessary. The plugs should be on a ground fault interruptor system or individually protected
• emergency lighting
• separate, locked storage rooms and preparation rooms to which students' access is restricted with approved storage areas for all classes of chemicals in the school. See the recommendations on page 76 of Science Safety Manual.
• adequate shelving so that materials do not have to be stacked, unless it is appropriate to store them that way
• an audiovisual storage area for charts, video and audio tapes, slides, and journals
• a storage area for student assignments

Safety

The Workplace Hazardous Materials Information System (WHMIS) regulations under the Hazardous Products Act govern storage and handling practices of chemicals in school laboratories. All school divisions should be complying with the provisions of the Act. Under WHMIS regulations, all employees involved in handling hazardous substances must receive training by their employer. If you have not been informed about or trained in this program, contact your director immediately. For more information, contact the Canadian Centre for Occupational Health and Safety, or Saskatchewan Human Resources, Labour and Employment.

Safety can not be mandated by rule of law, or by teacher command or by school regulation. Safe practice in the laboratory is the joint responsibility of the teacher and student. The teacher's responsibility is to provide a safe environment and to make the students aware of safe practice. The student's responsibility is to act intelligently based on the advice which is given and which is available.

Each school should have a copy of Science Safety Manual. Refer to Science: A Bibliography for the Secondary Level - Biology, Chemistry, Physics for information about ordering that resource and those listed below.

Other sources of information about safety in the chemistry classroom are:

Safety in the Secondary Science Classroom. (1978). National Science Teachers Association, 1742 Connecticut Avenue North West, Washington, D.C. 20009.

Prudent Practices for Handling Hazardous Chemicals in Laboratories. (1981). Washington, DC: National Academy Press.

A Guide to Laboratory Safety and Chemical Management in School Science Study Activities. (1987). Saskatchewan Environment and Public Safety, Regina. (A copy was sent to all schools in 1987.)

Hazardous Waste

The following are some general rules to help determine if the chemical waste being produced in your lab is hazardous. They are taken from an uncopyrighted newsletter distributed by the Chemical Health and Safety Committee of the Chemical Society of Washington, DC. Hazardous materials include:

• any solvent or solvent solution with a flashpoint of 60°C or less
• halogenated solvents (e.g. chloroform, hexachlorophene)
• oxidizers
• liquid with a pH of <2 or >12.5
• compounds containing sulfides or cyanides
• pesticides
• compounds or solutions containing heavy metals or heavy metal ions such as lead, chromium, cadmium, mercury and silver
• highly toxic chemicals (e.g. formaldehyde, colchicine)

A good rule is "When in doubt, don't throw it out!" If you have hazardous waste, store it in a secure place and get advice on what to do with it.

Disposing of Chemicals

A Guide to Laboratory Safety and Chemical Management in School Science Study Activities (Saskatchewan Environment, 1987) groups chemicals by disposal category. References to disposal categories in the following paragraphs are taken from that guide. See the Bibliography for ordering information.

• Chemicals in disposal categories 3 to 16 can be treated as hazardous waste unless they are chemically altered to fit into categories 1 or 2.
• The disposal of liquid or aqueous wastes containing substances from categories 1 and 2 should involve dilution before pouring them down the drain, then running tap water down the drain to further dilute their strength.
• Solid wastes from disposal categories 1 and 2 should be rinsed thoroughly with water. Then they should be disposed of in a specially marked waste container - not the general class waste basket. The janitor should be alerted to the existence of this container and be assured that none of the materials are hazardous.
• Wastes containing materials from disposal categories 3-16 should be stored securely on site until arrangements are made for appropriate disposal. Set aside some space which is used only for storage of waste chemicals.
• Using microscale activities can greatly diminish the amount of chemicals which need disposal.
• Caution should be exercised when disposing of chemicals.

Spill Mix (for most types of spills)

Note: For mercury spills use commercial kits. Any use of mercury or compounds which contain mercury should be discontinued.

• 1 part soda ash (anhydrous Na₂CO₃)
• 1 part clay cat litter
• 1 part dry sand

Mix equal volumes of each of these components thoroughly. Store it in plastic pails which have lids that seal. Ice cream pails or large white plastic lard or shortening pails are possibilities. Scoop or pour onto spill and allow to sit for a short time. Store the used mix in a sealed container. Dispose of the used mix in a manner that is appropriate to the type of chemical spilled. If the mix was used on an inorganic acid, it may be disposed of in an ordinary landfill. If it was used on an organic solvent, it should be disposed of in the same way the pure solvent would be.

Laboratory Practice

Safety in the classroom is of paramount importance. Other components of education - resources, teaching strategies, facilities - attain their maximum utility only in a safe classroom. Safety is no longer simply a matter of common sense. To create a safe classroom requires that a teacher be informed, be aware, and be proactive and that the students listen, think and respond appropriately.

Safety sessions are often offered at science teachers' conventions. Many articles in science teachers' journals provide helpful hints on safety. Professional exchange may provide teachers with an outside viewpoint on safety.

Encourage students to become aware that they must accept a large measure of the responsibility for their own safety. They can only do this if they are properly educated about what is safe. Once this education has begun, encourage the students to think about their actions. Such encouragement may take the form of safety-related questions on exams, preparing an outline of safety precautions in a laboratory activity as part of the prelab preparation for the activity, using a safety contract signed by the student, parent(s) and teacher, and the modelling of safe practice in the laboratory. A sample safety contract is found on page 171 of the Science Safety Manual.

Awareness is not something that can be learned as much as it is developed through a visible safety emphasis: safety equipment such as a fire extinguisher, a fire blanket, and an eye wash station prominently displayed; safety posters on the wall; a "safety class" with students at the start of the year; and regular emphasis on safety precautions while preparing students for activities.

Proaction is accomplished by acting on what is known and on what one is aware of. Six basic principles guide the creation and maintenance of a safe classroom.

• Model safe procedures at all times.
• Instruct students about safe procedures at every opportunity. Stress that they should remember to use safe procedures when experimenting at home.
• Close supervision of students at all times during activities, along with good organization, can avert situations where accidents and incidents can occur. Inappropriate behaviours in a classroom, and more particularly in a laboratory, can result in physical danger to all present and destroy the learning atmosphere for the class.
• Be aware of any health or allergy problems that students may have.
• Display commercial, teacher-made, or student-made safety posters.
• Take a first aid course. If an injury is beyond your level of competence to treat, wait until medical help arrives.

James A. Kaufman, a chemistry professor at Curry College in Milton, MA and editor of the newsletter Speaking of Safety, lists three important principles for laboratory health and safety:

• Be Aware. Know the hazards before you do the experiment.
• Be Prepared. Answer the questions:
  • What are the worst things that can go wrong?
  • What must I do to be ready for these things?
• Be Protected. Make health and safety an integral part of your activity.

From the newsletter of the Chemical Health and Safety Committee of the Chemical Society of Washington, DC come some examples of safety-related errors of omission and commission discovered during a survey and inspection of high school laboratories in the Washington area. The terminology has been adapted for Canadian situation.

• eye or face protection not continuously worn where circumstances dictate it should be
• eye or face protection which does not meet CSA standards
• loose clothing, long unrestricted hair or dangling jewellery worn
• labels and Material Safety Data Sheets (MSDS) not in accordance with WHMIS regulations
• storage of chemicals not conforming to WHMIS standards
• poor housekeeping with cluttered table tops and glassware in sinks

From the Speaking of Safety newsletter are some ideas for making your classroom a safer place.

• One teacher carries a double copy sales slip pad in her lab coat. When she sees a student violating a safety rule, she gives that student a citation. The citations count as points against the student's `lab license'. When a particular level of points have been accumulated the student loses the right to be in the lab. (The points accumulated could also be tied to the lab mark - inversely related of course!)
• A high school teacher has every student once in a term do a critique of another student's work. (The criteria for the critique could be given to the students, or the class as a whole could develop the criteria. The critique may focus only on safety or it may cover other aspects of work.)
• Another teacher offers a bonus point to everyone in the class if no one needs to be reminded to wear safety goggles. If one person needs reminding, no one gets the bonus point.

To compile a complete list of safety tips is impossible. To compile a comprehensive list would be to duplicate the materials which have been referenced previously. What follows is a 'highlights' list. This list does not diminish the responsibility of each teacher to be functioning at the highest level with respect to creating a safe classroom climate.

• Check your classroom for hazards on a regular basis.
• Create a bulletin board display with a safety theme.
• Make a rule that all accidents must be reported to the teacher.
• In case of a serious accident, pick one person who is present and send that person for expert, professional, or additional help. Then, take action. Remember, you are in charge of the situation.
• Become familiar with the school division's accident policy.
• Do not give medical advice.
• Move an injured person as little as possible until the injury assessment is complete.
• Emphasize that extra caution is needed when using open flames in the classroom.
• Require the use of goggles when using open flames, corrosive chemicals or other identifiable hazards.
• In case of fire, your first responsibility is to get students out of the area. Send a specific person to give an appropriate alarm. Then assess the situation and act.
• Avoid overloading shelves and window sills.
• Properly label, according to WHMIS standards, all containers of solids, liquids, and solutions.
• Separate broken glass from other waste.
• Advise students not to touch, taste, or smell chemicals unless instructed to do so.
• Each laboratory should have one first aid kit which is not accessible to students, but is only for the teacher's or administrator's use.
• Master shut-off controls for gas, electricity, and water should be tested periodically to ensure that they are operable.
• Safety equipment such as fire extinguishers, fire blankets, eye wash stations, goggles, fume hoods, test tube spurt caps, and explosion shields must be kept in good order and checked regularly.
• Electrical cords must be kept in good condition, and removed from outlets by grasping the plug.
• Students should use safety equipment - protective eye wear, protective aprons or coats, fume hoods, etc. - whenever practical and necessary.
• Students should tie back long hair and refrain from wearing loose and floppy clothing in the laboratory.
• Students should not taste any materials, eat, drink, or chew gum in a laboratory.
• Students should follow recommended procedures and check with teachers before deviating from such procedures.
• Students should be required to return laboratory equipment to its proper place.
• Chemicals or solutions should never be returned to stock bottles.
• Pipetting should be done only with a safety bulb, never by mouth.
• If, for any reason, substitutions are made for chemicals in activities, it is the responsibility of the teacher to research the toxicity and potential hazards of these substituted materials.
• Be aware that mixing acids or oxidizers with compounds containing chlorine (e.g., bleach) can generate chlorine gas.
• Mercury thermometers should be replaced with alcohol thermometers.
• Asbestos centred wire mats should be replaced with plain wire mats or with ceramic centred mats.
• Chemicals should be stored in a locked area, to which access is restricted.
• Be prepared to handle all chemical spills rapidly and effectively.
• Inspect glassware (e.g., beakers, flasks) for cracks and chips before using them to heat liquids or hold concentrated corrosive liquids or solutions.
• Chemical storage should be organized by groups of compatible compounds, rather than by alphabetical order. (Within a group of compatible compounds, alphabetizing can be used.)
• Electrical equipment (e.g., transformers, induction coils, electrostatic generators, oscilloscopes, discharge tubes, Crookes tubes, magnetic effects tubes, lasers, fluorescent effects tubes and ultraviolet light sources) must be kept in locked storage.
• Discharge tubes can produce x-rays which may penetrate the glass of the tube if operating voltages higher than 10 000 volts are used.
• Lasers are capable of causing eye damage. The lens of the eye may increase the intensity of light by 1 000 000 times at the retina compared to the pupil. To reduce risk, lasers rated at a maximum power of 0.5 mW should be used.
      - Lasers should be used in normal light conditions so pupils are not dilated.
      - Everyone should stay clear of the primary and reflected paths.
      - Everyone should be alert to unintended reflections.

Contact Lenses

Contact lenses complicate eye safety. Dust and chemicals may become trapped behind a lens. Gases and vapours may cause excessive watering of the eyes and enter the soft material of the lens. Chemical splashes may be more injurious due to the inability to remove the lens rapidly and administer first aid. The loss or dislodging of a contact lens may cause a safety problem if it happens at a crucial moment.

On the other hand, contacts, in combination with safety eye wear, are as safe as eyeglasses in most cases. Contacts may prevent some irritants from reaching the cornea, thus giving the eye some measure of protection. The Saskatchewan Association of Optometrists feels that, as long as proper, vented safety goggles are worn, there is no greater risk in a lab situation for a person wearing contacts than for one not wearing contacts. The Association recommends that:

• teachers know which students wear contact lenses
• teachers know how to remove contact lenses from students' eyes should the need occur
• there be access to adequate areas for the removal and maintenance of contact lenses
• contact lens wearers have a pair of eye glasses to use in case the contact lenses must be removed.

A Broader Look at Safety

Normally, safety is understood to be concerned with the physical safety and welfare of persons, and to a lesser degree with personal property. The definition of safety can also be extended to a consideration of the well-being of the biosphere. The components of the biosphere - plants, animals, earth, air and water - deserve the care and concern which we can offer. From knowing what wild flowers can be picked to considering the disposal of toxic wastes from chemistry laboratories, the safety of our world and our future depends on our actions and teaching in science classes.

Measurement

An understanding of the importance of measurement in science is critical for each student to acquire. The importance of measurement can be seen when it is viewed as one component of the Common Essential Learning of Numeracy. There is an implicit assumption in science, and in society, that quantitative statements are more authoritative than are qualitative statements. Yet, many important advances in science are made through intuition and through creative leaps. Advances in science are not restricted to data analysis. Students must see that measurement is important, but important in its context.

To make quantitative statements, measurements must be made. The accuracy of the measurements determines the confidence placed in the facts which are derived from the measurements. If the facts are represented as being accurate, the measurements must be equally accurate. But accuracy is not the only factor to consider when measurement is discussed.

The ability to make measurements depends on the technology available. A metre stick can be used to measure the length of a table. What technology is available to measure the diameter of an atom? Such measurements require a greater degree of faith in the technology. At the furthest reaches of scientific inquiry, technology must be devised so that the results of exotic experiments can be detected, measured, and interpreted. What is measured depends upon the assumptions made in the design, and on the limitations of the technology.

The ability to make measurements depends on the correct use of the technology. Proper procedures must be followed, even with the use of simple devices such as thermometers, if measurements which accurately represent the system under observation are to be made. In addition to proper procedures, the measurement devices must be used appropriately. Even though a thermometer has a ruled scale, to measure the length of a pencil in degrees Celsius is not a useful way to represent length.

There must be as little interaction as possible between the technology, or application of it, and the object being measured. If the device used to measure the temperature of a system changes the temperature of that system by a significant amount, how useful is the measurement? Heisenberg faced a similar problem in attempting to determine the momentum and the position of the electron in the atom. Precision in determining one results in less information about the other.

Before the matter of accuracy is addressed, the student must have an understanding of what technology is available, its appropriateness for the situation, the proper use of that technology, and the limits which are inherent in the technology. Once that is understood, the student can then manipulate the technology to give the most accurate and precise results.

One aspect of accuracy pertains to the matter of uncertainty in measurement. The percentage error in a measurement, or the absolute error, is a concept which students must deal with. No measuring instrument has zero margin of error. No operator is capable of using an instrument so that no measurement error is introduced. Measurement error exists and must be accounted for in recording and interpreting data. A particular balance may have an uncertainty of measurement of 0.01 g, for example, if the balance is levelled, properly adjusted, and working well. This balance has a suitable accuracy for measuring a mass of 142.87 g but not for measuring a mass of 0.03 g. Calculate the percentage error in each case and the point is clear. However, the 0.007% measuring error for the 142.87 g mass which is due to the balance may be made entirely insignificant by operator errors such as having the balance pan on the wrong hook, misreading the scale, not zeroing the balance before starting, stopping the oscillation of the beam with a finger, using a wet or dirty pan, and so on. Accuracy requires both good technology and good technique.

Another concern is that of significant figures. Measuring instruments can only supply a limited degree of accuracy. The problem most often encountered with students is to have them make use of the maximum precision possible, without having them overstate their case. If seven identical marbles have a total mass of 4.23 g, the average mass of a marble is not 0.604 285 714 g. A more reasonable report would express the average mass rounded off to two decimal places.

Many texts have sections dealing with the reporting of uncertainty in measurement and significant figures. Each teacher of chemistry should find an approach that is comfortable for both the teacher and the students and then adopt and emphasize that approach.

Data analysis is an important related topic. Often, in order to make sense of measurements, data must be organized and interpreted. Students must learn to organize their data collection and recording so that it is ready for analysis. Graphical analysis is often useful and should be stressed. The use of computer software is also an option for recording and analysis. Databases can be used to store and then manipulate large amounts of data. Spreadsheets are also useful for organizing data. Many database and spreadsheet programs, as well as integrated software packages, contain graphing utilities and may contain statistical analysis options. Graphing and statistical analysis packages may also be purchased as stand-alone software. The use of computer analysis should be encouraged wherever possible.

In addition to the use of computer analysis, hardware interfaces to allow the input of data through sensors, which the software then interprets as measurements, are a valuable addition to a science lab. It should be emphasized that the use of a computer does not mean that the results will be error free. Accuracy is mainly a function of the technician and, to a lesser degree, of the technology.

Measurements should be expressed using SI units, or SI acceptable units, whenever this is realistic or feasible to do so. Common non-metric units may be used if necessary. Conversion factors from non-SI to SI or within the non-SI units may be necessary. Each teacher should follow the recommendations of the Canadian Metric Commission with respect to the basic and derived units of measurement and the proper symbols for those units.

If detailed information is required, refer to the Canadian Metric Practice Guide (CAN3-Z234.1-79 from the Canadian Standards Association, 178 Rexdale Boulevard, Rexdale, Ontario M9W 1R3), the International System of Units (SI) (CAN3-Z234.2-76 from the CSA) or the SI Metric Guide for Science (Saskatchewan Education, 1978).

Scientific notation should be used so that students become familiar with reading, manipulating, and writing numbers in that format. In addition to the value of SI-notation for ease in handling very large or very small numbers, students must be able to use this notation to express the number of significant figures in a large number, and to perform calculations using scientific notation.

Organizing a Field Trip

Field trips can and should be valuable learning experiences which allow students to apply their classroom learnings to an actual or "real" situation. Field trips also allow students the opportunity to learn directly rather than indirectly. Learning is enhanced through direct experience. Field trips are fun for everyone involved! Use Out to Learn.

The key to successful field trip experiences is careful and thorough planning. This planning takes time and patience. Make sure to check to see if the school division has any special policies regarding field trips.

The simplest approach when planning a field trip is to treat the experience like the writing of a newspaper article, using the five Ws.

Why do you want to take your class on this particular trip?

Have leaders responsible for coordinating the groups' activities been selected for the working      groups?

Although this may seem like a great deal of work, planning should be done before embarking on a field trip. The more concrete and detailed the planning is, the more likely it is that the trip will be a success.

Once the groundwork has been set and administrative approval has been obtained, approach the parents and the students about the trip. It is advisable to send a letter home to the parents which details the proposed field trip. Include information on such things as the times of departure and return, the location of the field trip, the people responsible for supervision, clothing requirements, lunch plans, required materials, anticipated costs, and contingency plans. This letter could also include a request for parental help and a separate permission slip to be returned to the teacher. It is a good idea to have the letter signed by both the teacher and the principal before sending it to parents.

The parental consent form which follows serves as an example of one that could be used. Note that the use of a consent form does not remove the teacher or the school division from the possibility of incurring liability during the trip.

---

Facilities

Safety

Hazardous Waste

Disposing of Chemicals

Spill Mix

Laboratory Practice

Contact Lenses

Broader Look at Safety

Measurement

Organizing a Field Trip

Sample Permission Form

Sample Permission Form for Field Trips

Date: Dear Parent/Guardian: As a part of the chemistry program, we will be going on a field trip to _________________. This field trip will provide your daughter/son with the opportunity to experience the following: (provide a brief list of the activities you have planned). An itinerary and a schedule of our proposed activities during the field trip is included for your information. Please review this material and contact the school if you have any questions about our plans. Your daughter/son should bring the following supplies on the field trip: (list any special needs). If she/he has any special physical or medical problems (e.g., allergies), please bring this to our attention. Contact the school if you feel that these problems may interfere with your daughter/son 's participation in this activity. We would like you to come along on this exciting learning experience. We encourage you to sign up as a volunteer. Thank you for your cooperation. ___________________                       ___________________ Teacher                                                     Principal Consent Form I will be able to take part in this field trip as volunteer. Yes___   No___ Comments:____________________________________________________ I permit _____________ to take part in the field trip described above. I have notified the school of any physical or medical problems which might interfere with my daughter/son's participation in this activity. Date: Signature: