Appendix C: Safety Guide by Topic
While many experiments in this book are simple, safe, and home-friendly, some involve tools, materials, or environments that deserve extra caution. This appendix organizes key safety notes by topic, helping you anticipate and avoid common risks as your explorations grow in depth and complexity.
Science is a joyful, hands-on activity — and with thoughtful care, it remains just that.
Heat, Fire, and Temperature
- Thermal Cameras & Heated Objects: Infrared cameras like the CAT S60 allow for fascinating temperature studies, but never direct them at overly hot objects like open flames or heating elements.
- Experiments Involving Hot or Boiling Water: Use heat-resistant containers. Avoid sealing heated water in airtight vessels. Always allow hot materials to cool before handling.
- Sunlight as Heat Source: When focusing sunlight (with lenses or mirrors), never aim toward people or flammable materials. Supervise all sunlight-based experiments.
Lasers and Bright Light
- Sunlight and Magnification: Never look at the Sun through binoculars, telescopes, camera lenses, or any magnifying device without a certified solar filter. The concentrated light can cause instant and irreversible eye damage.
- Laser Safety: Use low-power (Class 1) laser pointers. Never direct lasers into eyes, mirrors, or reflective surfaces. Even brief exposure to high-intensity beams can cause permanent damage.
- Flashlight or LED Dazzling: Be aware that direct, sustained exposure to the flashlight of a smartphone at close range can be uncomfortable or harmful to the eyes.
- Polarizers and Sunglasses: Only use filters and polarizers that are explicitly rated as safe when looking toward the Sun. Never use stacked sunglasses, CDs, or unapproved materials.
Electricity and Electronics
- Batteries and Voltage Sources: Even small batteries can be dangerous when short-circuited. Avoid connecting 9V or lithium batteries directly to metal surfaces or liquids.
- Capacitors: Some devices (especially older electronics) can retain charge. Avoid disassembling unknown circuitry unless you understand how to discharge stored energy.
- DIY Circuits: If you build simple circuits for input/output through the microphone or USB ports, always verify voltage and current levels. Use resistors and isolation components like capacitors, for instance, as needed.
Magnets and Magnetic Fields
- Neodymium Magnets: These are extremely strong and can snap together with painful force. Keep away from electronics, credit cards, computers, and sensitive instruments. Never allow near children without supervision.
- Interference with Sensors: Strong magnetic fields can temporarily disrupt or permanently damage sensors. Always test gradually and at a distance.
Chemicals and Materials
- Household Chemistry: If using baking soda, vinegar, salt solutions, or similar substances, label containers clearly. Avoid ingestion or eye contact.
- UV and Fluorescent Materials: If exploring UV light, wear protective eyewear. Never use UV sources not designed for educational or consumer use.
- Biological Materials: Avoid handling mold, decaying matter, or unknown microorganisms. If using plant materials or yeast, maintain hygiene and discard samples safely.
Motion, Impact, and Physical Objects
- Dropping Phones or Objects: Experiments involving falling, swinging, or sliding phones should be conducted with cushions, padded surfaces or safety tethers.
- Spinning or Vibrating Devices: Be alert to unsecured setups. Sudden motion can cause phones or objects to fly off tables or mounts.
- Rubber Bands and Tension: When stretching elastic materials, wear protective eyewear and avoid aiming toward people. Always inspect for wear before reuse.
Radioactivity and Radiation
- Low-Level Sources Only: Use only consumer-safe radioactive sources, such as old radium dials, uranium glass, or NoSalt (potassium chloride). Do not attempt to acquire or handle anything beyond educational-grade materials.
- Measurement Devices: DIY Geiger counters using camera sensors are exploratory, not certified. Treat all results with caution and respect proper disposal of any material used.
Environmental Awareness
- Water and Electronics: Even in waterproof phones, avoid prolonged submersion, especially in salt water or hot environments. Double-bag phones in water-tight experiments.
- Outdoor Experiments: Be aware of traffic, weather, and visibility. Never conduct long-exposure experiments on roadsides or near drop-offs. Tell someone where you’re going.
- Nighttime Stargazing: Always carry a flashlight, dress warmly, and avoid isolated locations when observing alone.
Final Reminder
Scientific safety is not about avoiding risk altogether — it is about understanding, minimizing, and managing risk intelligently. Treat your environment, your tools, and your body with respect, and you’ll find that safe science is not limiting — it’s empowering.