Demonstrations are an integral part of any science program. These activities engage students and help bring the “real world” into the classroom. STAO has recently developed a collection of safe demonstrations/activities for grades 9 and 10 that have been designed to challenge students’ thinking as well as initiate lively classroom discussions that support constructivist learning. These short demonstrations/activities often involve discrepant events related to the topic of focus in the grades 9 and 10 science curriculum, that may surprise students and that can be observed and/or investigated safely by students in the classroom. These demonstrations/activities are available for free download at http://stao.ca/res2/demoover.php
Planning a Demo
- Consider how the demonstration/activity relates to curriculum policy
- Build in ‘think’ time in order that students have enough time to think about the demo and not just complete it; if students do not have enough time to analyse what happened and why, they may not get much benefit from the investigation
- Know the chemicals or materials you use and what will happen; refer to the MSDSs as needed
- Check all school board policies and provincial regulations that might apply to using these specific chemicals or materials
- Do the demonstration/activity yourself ahead of time; consult experienced teachers
- Be sure that sufficient cleanup time, if required, is built into the demonstration/activity
- Make sure you are aware of the proper method of disposal for all materials used in the demonstration/activity
- The teacher must be present in the classroom at all times during the demonstration/activity, and must be familiar with the classroom and school emergency equipment and systems
- When conducting demonstrations, students should be kept a minimum distance of 1 m away from the demonstration area; a safety screen may be employed if the demonstration warrants it
- Ensure that areas where investigations are to be conducted are kept clear of combustible materials and obstructions
- Deliver just-in-time instructions
- Leave stock bottles in prep room
- Model appropriate safety precautions, including eye protection; both teacher and students should wear appropriate PPE (Personal Protective Equipment)
- Don’t risk body parts (tasting, touching)
Fire Safety in the Classroom
- Use the smallest possible quantity/volume of a chemical – if necessary, use a video cam or projector to make the demo visible
- Use lower/safer concentrations of reagents
- Use safer alternative, i.e., not flammable or combustible and less toxic
- Use hot plates instead of open-flame burners
- Have your fire and other emergency equipment available
NOTE: The Office of the Fire Marshal guideline, ‘Handling Flammable and Combustible Liquids in School Laboratories’, Section 3.0
‘Before using any flammable or combustible liquids be sure that all sources of ignition such as open flames, hot surfaces, radiant heat, spontaneous ignition, frictional heat or sparks, static electricity, electrical sparks, stray currents, ovens, furnaces, and heating equipment (Bunsen burners, candles, hotplates or spark generating appliances) are eliminated.’
- Be sure that no one (students) has any uncontrolled ignition sources, such as matches or lighters, etc. that may inadvertently be used to ignite a flammable liquid.
- Allow sufficient cooling time (back to room temperature) of any lab equipment before attempting to re-engage the use of any flammable and combustible liquids.
- STAO’s Fire Safety Resource
- The guideline developed by the Office of the Fire Marshal, ‘Handling Flammable and Combustible Liquids in School Laboratories’, includes specific information about required training (section 1.0) and recommended procedures for handling flammable and combustible liquids (section 3.0).
- NSTA, 2004, Investigating Safely: A Guide for High School Teachers
- STAO’s Safe ON Science (SOS) resource describes safety considerations for activities in physics, chemistry, and biology that will help to mitigate safety problems in the school laboratory.