Work safely with an alcohol lamp
The flame fixes your smear, sterilises your loop, and is nearly invisible in a bright room. Learn the four habits that keep it useful instead of dangerous.
- Heat is a sterilising method: A loop held in a flame until it glows has nothing living left on it, which is why flaming replaces washing for that tool.
- Alcohol vapour catches, not just the liquid: The fuel that burns is the vapour above the wick, which is why an open or hot lamp near a flame is the hazard rather than the liquid itself.
Prerequisites are inferred: pending teacher review.
Re-learn the skill with worked practice and clear examples.
Now look after the lamp itself, which is a container of flammable liquid with a flame on top of it.
Why is an alcohol lamp put out with its cap rather than by blowing it out?
Reviewed- A.Breath carries moisture that stops the lamp relighting
- B.Blowing can push burning fuel off the wick; the cap cuts off air
- C.The cap has to go on afterwards anyway, so blowing wastes a step
- D.Blowing cools the wick unevenly and shortens its life
Show the worked solution ▾
Answer: B. Blowing can push burning fuel off the wick; the cap cuts off air
- Step 1: Ask what blowing does mechanically: It pushes air and anything on the surface of the wick sideways, and what is on the wick is burning fuel.
- Step 2: Compare with the cap: The cap removes the air supply without moving anything, so the flame stops where it is.
Why it's right: Blowing pushes at burning fuel on the wick and can carry it off the lamp. The cap stops the flame by removing its air supply and moves nothing at all.
- A: Moisture from breath does not prevent an alcohol lamp lighting again, and relighting is not the concern.
- C: Capping is indeed the next step either way, and saving a step is a convenience argument rather than the safety reason.
- D: Wick life is a consumable question and would never be the reason a safety instruction is written.
Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9
A lamp runs low during a busy period. When is it safe to top it up?
Reviewed- A.At any time, provided gloves and goggles are worn
- B.Immediately after capping it, while the wick is still warm
- C.Once it is out and fully cool, away from any other flame
- D.While it is lit, as long as the fuel is poured slowly from the side
Show the worked solution ▾
Answer: C. Once it is out and fully cool, away from any other flame
- Step 1: Ask what actually ignites: The vapour coming off the fuel, not the liquid in the reservoir.
- Step 2: Remove every ignition source: That means no flame nearby and no hot surface, which requires the lamp to be out and cool.
Why it's right: It is the vapour that ignites, so the fuel has to be poured with no flame nearby and nothing hot enough to set it off. That means the lamp is out and cool, not merely capped.
- A: Gloves and goggles protect against a splash and do nothing about a flash of igniting vapour.
- B: A capped lamp with a warm wick still has a hot surface and vapour above it, which is the exact combination being avoided.
- D: Pouring fuel near a live flame puts a stream of flammable vapour directly into it, whatever angle it is poured from.
Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9
- A student caps the lamp between transfers rather than leaving it burning on a bench nobody is standing at.
Fill these in as you work through the lesson.
- Heat fixation (flame passes that stick cells to glass):
- Striker (the sparker used to light the lamp):
- Snuff (put out by cutting off air):
- Aerosol (tiny droplets thrown into the air):
Put an alcohol lamp out with its rather than by blowing, never refill one that is , and let a flamed loop before it touches a culture.
- Explain what heat fixation does for a smear.
- Give the reason a hot lamp is never refilled.
- Say what happens if a red hot loop is put straight into broth.
You finish flaming. Instead of leaning over and blowing the lamp out, you lower the cap onto it. The flame goes out because the air is cut off, nothing is scattered, and the cap also stops the fuel evaporating away between lessons.