S1.1 Experimental techniques

Identify the hazard

State the physical or environmental hazard first: ionizing radiation, toxic exposure, uncontrolled energy, mining damage, landfill or contamination. A valid evaluation connects the technology to a concrete consequence.

Frame an ethical choice

Compare benefits and harms for the affected people. For a medical isotope, balance possible treatment benefit against side effects and the consequence of not treating; do not present a medical choice as risk-free.

Discuss rather than list

A discussion needs more than one perspective or consequence and a reasoned comparison. For environmental questions, consider extraction, use, disposal and long-term effects.

Common trap

Do not write a vague claim such as “it is dangerous.” Name the mechanism and the consequence, then connect it to the decision.

Prepare the instrument

Choose an instrument whose range and resolution suit the variable. Check zero, calibration and units before measuring length, mass, time, temperature, force, current, potential difference, angle, sound or light intensity.

Read the value

Record enough digits to reflect the instrument’s resolution and include the unit. For a corrected reading, apply the zero offset with the correct sign; a displayed value is not automatically the true value.

Improve reliability

Repeat measurements, average them, and measure at different positions or orientations when geometry permits. This reveals random variation and reduces its effect on the mean.

Common trap

Do not increase precision by writing extra decimal places that the instrument cannot resolve, and do not correct a zero error in the wrong direction.