Why should experiments never be left unattended?

Experiments should never be left unattended primarily because it can lead to uncontrolled reactions or fires. In a laboratory setting, many chemical reactions can be unpredictable. If adjustments need to be made or if something goes wrong, having someone present ensures that immediate action can be taken to mitigate risks. An unattended experiment may reach temperatures or pressure levels that are unsafe, possibly resulting in hazardous situations such as explosions, chemical spills, or fires.

Vigilance during experiments allows for quick assessment and intervention in case of unexpected changes, thus prioritizing safety for all individuals in the laboratory. The presence of a responsible individual can make a significant difference in preventing accidents and ensuring a controlled environment while conducting potentially dangerous chemical reactions.