Mechanical hazards: article updated for students and trainees

Introduction

Physical hazards include mechanical hazards, electrical, heat, sound, and radiation hazards that may occur in physics laboratory activities, as well as a variety of other science activities.

Hazards in each of these categories have the potential to cause injuries (or, in some extreme cases, even death), but by taking general precautions, such as using appropriate protective equipment and emphasizing routine safety, physical hazards can be easily minimized.

Mechanical Hazards Control

• In general, safety can be increased by ensuring that equipment is well
  maintained.

• Turn off all equipment before leaving the area.

• Students must only use equipment with teacher supervision.

Rotating Machinery

Machinery with rotating parts can catch loose clothing, hands, or hair,
potentially causing serious injuries.

Uncovered parts may also fly off, thereby creating additional risk, especially for eye injuries.

To minimize risks, do the following wherever possible:

• Ensure rotating shafts, belts, and pulleys are covered by guards, lids, or covers.

• Check devices attached to a rotor before use to ensure that they are tightly fastened.

• Wear (and have students wear) eye protection when using uncovered,
  rapidly rotating parts, as in the demonstration of centripetal force and circular motion.

• Have students stand back as much as possible.

• Have a safety shield available in the science area.

Tools

Careless use of tools or use of tools in poor condition can cause injuries to the hands, eyes, head, and limbs.

To minimize risks:

• Regularly check tools for defects or damage.

• Damaged tools should be immediately removed from student use.

• Provide students with clear instructions on safe use before they have access to tools.

Cutting Tools

By design, these instruments (i.e Scalpels, Razor Blades ..etc) are very sharp. Careless use can quickly result in deep cuts.

To minimize risks:

• Use extreme caution in handling cutting tools, and ensure that students do the same.

• Replacement of blades is best done by teachers or technicians.

• Wear eye protection when using cutting tools in case a blade breaks.

Magnets

Large, powerful magnets or electromagnets can attract other magnets or iron/ nickel objects with surprising force, which can cause painful pinching of fingers or hands.

To minimize risks, Inform students of this hazard before such magnets are used.

Glassware

Any kind of glassware has the potential to break, creating the risk for cuts or spilled materials.

To minimize risks:

• Wear goggles for eye protection.

• Use heat-resistant glassware, which is less likely to crack when heated.

• Avoid using glass containers that are cracked or chipped, since they may crack further during the experiment.

• Clean up any broken glass immediately and dispose of in a special waste bin dedicated to broken glass.

• Do not pick up glass with your hands—use a dustpan and brush or broom.

Projectile Launchers

Projectile launchers are often used in the study of motion—sometimes as
demonstration devices and sometimes as equipment for student laboratories.

Equipment used includes such devices as ballistic pendulums, commercially
available devices that launch plastic and steel balls, and classroom-constructed devices that launch a variety of materials.

When decisions are made regarding the use of such equipment—such as which devices are to be used, who will use them, and how to use them—it is important to recognize factors that can introduce potential risk.

These factors include the power of the launcher, the nature of the projectile, and the maturity, skill, and safety awareness of the user.

The location and orientation of the launcher when the device is operated
relative to the location of students is also a concern.

These devices should never be oriented in a way that puts students in the line of fire.

To minimize risks:

• Wear goggles for eye protection.

• Participants and spectators should be behind the line of fire.

• Avoid using projectiles with sharp points.

• Ensure that misfiring does not place participants or spectators at risk.

Testing Structural Design to Failure

The Early and Middle Years science curricula contain many activities where
students are required to make fair tests on various structures for design,
stability, strength, and efficiency of performance.

Such testing, particularly for strength, often requires stress-to-failure determination, which may require some precautions.

To minimize risks:

• Assess all inherent risks of testing to determine necessary precautionary measures.

• Wear goggles for eye protection.

• Minimize height at which testing is done on collapsing structures.

• Use of heavy weights should be closely supervised.

• Testing should be only attempted during teacher supervision.

• Testing should be done in a clearly marked area a safe distance from
  students.