Book 3, Question 140
Why Do Welders Wear a Dark Mask?
Welding light is brighter and harsher than a lamp. A dark mask is like a filter that blocks the extra brightness. It also blocks invisible rays that can burn eyes and skin!
From the book
Page from A Million Whys Book 3
More fun facts
- The light from arc welding contains very strong ultraviolet rays.
- Without a barrier, those rays spread out and can reach other workers nearby too.
- Welding UV often causes sore, inflamed eyes and red skin.
- In one study, the safe time to face an unshielded welding arc from half a meter away was only 0.23 to 5.9 seconds a day.
- Welding with higher electric current gave off more harmful UV than welding with lower current.
- Japan alone has about 350,000 professional arc welders who need protection.
Sources: National Institutes of Health
Questions kids ask
How long can eyes safely look at a welding arc?
Only seconds. In one study, the safe limit without protection was about a quarter second to six seconds a day.