Program Organization

Facilities and Materials

Facilities and materials, by themselves, do not create a science course. They are essential, but proper use of the facilities and materials is what is critical. Generally, the facilities which exist in most schools offering Secondary Level science courses will be adequate for teaching Biology.

Since a wide range of teaching strategies is desirable in this course, 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;
  
  
• adequate shelving so that materials do not have to be stacked, unless it is appropriate to store them that way;
  
  
• a separate chemical storage cabinet with provisions for proper storage of all classes of chemicals;
  
  
• an audiovisual storage area for charts, video and audio tapes, slides, and journals;
  
  
• areas for plant and animal care; and,
  
  
• a storage area for student assignments.

Materials which are normally available in a Secondary Level science laboratory will be adequate for doing most of the activities in Biology. Other materials may be needed, but they are readily available from suppliers of science materials.

Science equipment and supplies are valuable resources. Not only are they becoming more expensive, but they are also indispensable to the proper presentation of science. There are several reasons for having an efficiently operating inventory system. Such a system can prevent running short of a consumable supply, prevent ordering something already in adequate supply, and save time when ordering. It can act as a quick reference to determine whether a particular item is available. It may also be useful for insurance purposes.

Safety in the classroom is of paramount importance. Other components of education - resources, teaching strategies, facilities Ä 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. There are several ways the teacher can become informed. Consult the references below. Refer to Science: A Bibliography for the Secondary Level Ä Biology, Chemistry, Physics for ordering information on these items.

Each school should have a copy of the B.C. Science Safety Manual.

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

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.

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.

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.

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. To compile a "highlights" list would be to risk leaving out something important. To compile no list would be negligent. What follows is a highlight 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 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 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 Ä protective eye wear, protective aprons or coats, fume hoods, etc. Ä 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.
  
  
• Acids or oxidizers should never be mixed with compounds containing chlorine (e.g., bleach).
  
  
• Mercury thermometers should be replaced with alcohol thermometers.
  
  
• Asbestos centred wire mats should be replaced with plain wire mats or with ceramic centred mats.
  
  
• The use of human biological fluids in laboratory activities should be closely monitored.

  °Students should use only materials from their own body Ä blood, saliva, epithelial
  cells - when doing lab activities requiring those materials.
  °Students should have no contact with bodily fluids from another student.
  °The lancets used to obtain blood samples must be the disposable type, and must be used
  only once.
  °The lancets must be immediately and properly disposed.
  °Alcohol prep pads should not be used more than once.
  °Students should wash their hands thoroughly with soap and water after handling any bodily
  fluids.

• Specimens for dissection, dissecting tools and equipment, and chemicals used in biology must be kept under locked storage.
  
  
• When field materials such as pond or slough water, plants, soil, or insects are collected, assume that they are contaminated by pathogens and treat them as such.
  
  
• Known pathogens should not be cultured. Exposure plates and culture plates with unknown bacterial colonies must be treated as though they are contaminated by pathogens until it can be shown otherwise.
  
  
• Make sure that autoclaves are in good operating condition.
  
  
• Adequate ventilation is essential when working with specimens preserved in formalin or formaldehyde.
  
  
• Proper care must be given to animals kept in a classroom. Refer to a good animal care book, if needed.
  
  
• Use rubber gloves and take great care when handling any plant growth hormones such as colchicine, gibberellic acid, indole acetic acid, or Rootone^(TM).
  
  
• 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.
  
  
• Many plants may contain toxins or allergens. Students should be cautioned not to taste or handle plants. Teachers are responsible for familiarizing themselves with any local, provincial, or federal legislation pertaining to plants and animals. If in doubt, inquire.
  
  
• 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 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;
and,
°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 Ä plants, animals, earth, air and water Ä 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 Secondary Level laboratories, the safety of our world and our future depends on our actions and teaching in science classes.

The Workplace Hazardous Materials Information System (WHMIS) under the Hazardous Products Act governs storage and handling practices of chemicals in school laboratories. All school divisions should be complying with the provisions of the Act.

Some precautions should be followed when disposing of chemicals. See A Guide to Laboratory Safety and Chemical Management in School Science Study Activities.

• The disposal of liquid or aqueous wastes 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 should be rinsed thoroughly with water. They should be disposed of in a specially marked waste container Ä 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.

If, for any reason, substitutions are made for materials, it is the responsibility of the teacher to research the toxicity, potential hazards, and the appropriate disposal of these substituted materials.

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 science texts have sections dealing with the reporting of uncertainty in measurement and significant figures. The teacher 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).