Safe Practices in a High School Science Lab

3 Recent Classroom Accidents

1.Students injured in Science class blast

• demonstration of how different chemicals burn

• nearby bunsen burner ignited 1L beaker of methanol in teacher’s hand

• flames scattered onto students in front row

3 Recent Classroom Accidents

2.Science experiment burns student

• demonstration of whoosh bottle experiment

•more alcohol added after first demo

•flame shoots out of jug burning student about 2 metres

away from demo

3 Recent Classroom Accidents

3.Teacher and students suffer lacerations

in Science lab explosion

• demonstration of exothermic reaction –

potassium chlorate, manganese dioxide, sugar and glycerin

• teacher wearing safety glasses; students moved back

Know Your lab

ExitsLab door(s)Stop button (power)Glass disposal box (broom/dustpan)

Eye wash/showerFume hoodFire extinguisher(s)/ blanket(s)First-Aid kits

Prevent Problems

Traffic flow of students what can you do to minimize traffic and congestion?

Where to ‘stand & circulate’ during labs what can/will go wrong during labs always have a clear sightline of every student

How will materials/lab equipment be distributed & collected? have a student in charge from each station to retrieve/return the materials, also have a student who is on ‘clean up patrol’ where they need to wipe counters, inspect area and report back to you on the condition of their lab station.

Allow for startup and cleanup time. Including waste collection (and in some cases treatment and disposal)

Model safe behaviour (wear your goggles, tie your hair back etc…)

Only bring enough chemicals/equipment for what you need (easier to track its return and count).

Save time for clean-up and wrapping up the lesson.

Fire Safety Knowledge and Skills

Knowledge for Handling Flammable and

Combustible Substances

1. Type of Flammable and Combustible

Materials

2. Quantity of Flammable and Combustible

Materials

3. Concentration of Flammable and Combustible Materials

Fire Safety Knowledge and Skills

Knowledge and Skills for Preparation of Activities

4. Room Readiness

― Safety equipment

5. Storage and Disposal

6. Classroom Management

― Assessment of student skill level and

readiness

7. Choice of Heat Source

― Suitable flame source

Knowledge and Skills for Emergencies

8. Dealing with Unintended Flame

How to choose safe chemicals?

1. Consult your Board chemical list (if available)

2.Consult the HMIS rating on vendor MSDS

e.g., Boreal Northwest

www.boreal.com

Video 1 - H2, O2, and CO2

Video 1 - Testing Gases – H2, O2, and CO2

Video 1

Video 1 – Testing Gases H2, O2, and CO2

Discussion Questions

1. What categories (classes) of chemicals are used in this activity?

2. What specialised equipment is used?

3. What safety precautions were taken during this activity?

4. What classroom management concerns were addressed in the video?

Chemical Segregation in the Storage Room

Chemical Storage Groups (*adapted from SOS page 37)

Group Storage Provision Store Away From Flammable and Combustible liquids (e.g., alcohols)

Fire-resistant ‘Flammables Cabinet’

Oxidizers and toxics

Flammable and Combustible Water-reactive Solids (e.g., alkali metals)

Separate cupboard or cabinet

Oxidizers, corrosive liquids, and flammable liquids

Highly Toxic Chemicals (e.g., Mercury)

Usually banned by most boards

Flammable liquids

Corrosive Liquids, acids (e.g., conc. HCl)

Vented ‘Acid Cabinet’; HNO3 should be isolated

Non-acid corrosive liquids, water-reactive solids and toxics

Chemical Segregation in the Storage Room

Chemical Storage Groups (*adapted from SOS page 37)

Group Storage Provision Store Away From

Corrosive Liquids, bases (e.g., NaOH solution)

Not in glass containers Acids, water-reactive solids and toxics

Corrosive Solids (e.g., NaoH)

With general chemicals

Oxidizing Agents (e.g., peroxides, chlorates)

In plastic trays Flammable liquids/solids, water-reactive solids, organics, corrosive liquids

General Chemicals Inorganics/organics

Video 2 – Reactivity of Metals Li, Na, and K

Video 2 - Reactivity of Metals – Li, Na, and K

Video 2

Video 2 – Reactivity of Metals

Discussion Questions

1. What categories (classes) of chemicals are used in this activity?

2. What specialised equipment is used?

3. What safety precautions were taken during this activity?

4. What classroom management concerns were addressed in the video?

Video 5 – Ester Synthesis

Video 5

Summary - Application of Knowledge

Video 5 – Ester Synthesis

1. What safety precautions were taken during this activity?

Safe ON Science

Written by the STAO/APSO Safety

Committee

Available at the STAO/APSO online

store

www.stao.org