Shield your eyes at a UV transilluminator
Ultraviolet light gives you no warning while it is doing damage. Learn how the unit is meant to be looked through, when the lamp is off, and what to do when the shield is missing.
- Some hazards give no signal while they act: Heat tells you to move your hand. Ultraviolet light does not. A protection you only apply when something feels wrong will always be applied too late.
- Equipment usually comes with its own guard: A shield or lid built into a unit is part of the unit. Using the machine without it is using a different, less safe machine.
Prerequisites are inferred: pending teacher review.
Re-learn the skill with worked practice and clear examples.
Now decide when the lamp is off and what to do when the guard is not there.
When should the lamp be switched off?
Reviewed- A.It can stay on for the whole class once it has warmed up properly
- B.Whenever the room lights are on, because the two interfere with each other
- C.While hands are over the surface, so while the gel is placed and taken out
- D.Only at the very end of the session, once every group has sketched their gel
Show the worked solution ▾
Answer: C. While hands are over the surface, so while the gel is placed and taken out
- Step 1: List the moments your hands are over it: Putting the gel down and picking it up again.
- Step 2: Match the switch to those moments: Off for both, on only while you are looking through the shield.
Why it's right: The two moments your hands and face are closest to the lamp are the two moments the lamp does not need to be on. Switching off for both removes the exposure without costing you anything.
- A: There is no warm-up that makes an open lamp safe to lean over, and leaving it running through changeovers is the habit this rule exists to break.
- B: Room lighting affects how easily you see the bands, and it has nothing to do with when the lamp is safe to run.
- D: Leaving it on through every changeover means every group loads and unloads a gel over a live lamp.
Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9
A group cannot find the shield for their transilluminator. What should they do?
Reviewed- A.Tell the teacher, and not run the lamp until there is a shield or a face shield
- B.Use it briefly, since a few seconds of exposure will not do any harm
- C.Cover the top with a sheet of white paper and lift one corner to look underneath
- D.Use it with the lid open but look away in between glances at the gel
Show the worked solution ▾
Answer: A. Tell the teacher, and not run the lamp until there is a shield or a face shield
- Step 1: Ask what the missing part was doing: It was the only thing between the lamp and your eyes.
- Step 2: Ask whether there is a workaround: Not one a student can build at the bench.
Why it's right: The guard is not an accessory, it is the part that makes the machine safe to look at. With it missing there is no version of the task that is safe to improvise, so the run waits until the equipment is complete.
- B: Brief exposures are exactly the kind you cannot feel and cannot count, which is why the rule does not have a time limit built into it.
- C: Paper is not a viewing shield, and lifting a corner to look puts your eye at the gap where the light comes out.
- D: Looking away between glances still means looking straight at an unshielded lamp during each glance.
Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9
- A group stops and reports missing equipment rather than improvising a shield.
Fill these in as you work through the lesson.
- Transilluminator (lights the gel from below so bands show):
- Ultraviolet (light you cannot see and cannot feel):
- Shield (the hinged guard that comes with the unit):
- Delayed onset (the injury shows up hours later):
View the gel through the that came with the unit. Switch the lamp whenever your hands are over the surface. You cannot ultraviolet light while it is doing damage, so the protection goes on rather than when something hurts.
- Say why a hazard you cannot feel needs a rule rather than judgement.
- State when the lamp should be off.
- Describe what you do if the shield is missing.
You place the gel with the lamp off, lower the shield, then switch on and sketch what you see through it. When you are finished you switch off before lifting the shield to take the gel out.