A beaker is the most frequently used vessel in the laboratory — for dissolving, heating, mixing and roughly measuring liquids. Simple as it looks, choosing the right material and using it correctly matters: this guide covers beaker types, borosilicate vs soda-lime glass, capacity selection, and the do’s and don’ts of heating.
💡 Key Point
① Beaker graduations are approximate — never use them for quantitative measurement (use a volumetric flask or pipette instead). ② For daily work choose borosilicate 3.3, safe on open flames above 500°C. ③ Always heat on a wire gauze and avoid thermal shock.
1. Beaker Types and Uses
| Type | Feature | Typical Use |
|---|---|---|
| Griffin (low-form) beaker | Height ≈ 1.4× diameter; the most common | Dissolving, heating, mixing, reaction vessel |
| Tall-form beaker | Taller and narrower, less evaporation | Titrations, deep liquid columns |
| Spouted beaker | Pouring spout on the rim | Clean, drip-free pouring |
| Custom-printed beaker | Branded graduations / logos | Education, OEM, production lines |
2. Material: Borosilicate 3.3 vs Soda-Lime
Material determines heat resistance, chemical resistance and service life — the most important buying decision.
| Comparison | Borosilicate 3.3 | Soda-Lime Glass |
|---|---|---|
| Coefficient of expansion | 3.3×10⁻⁶/K (low, thermal-shock resistant) | ≈9×10⁻⁶/K (cracks easily) |
| Temperature rating | Safe above 500°C, open flame OK | ≤150°C typically |
| Chemical resistance | Resists acids, alkalis and most reagents | Poor vs strong alkali and HF |
| Price | Higher | Low |
| Best for | Analysis, heating, teaching & research | Disposable / simple room-temperature tasks |
3. Choosing the Right Capacity
- Common sizes: 50, 100, 250, 500 and 1000 mL cover most lab work; 5–10 mL micro-beakers and 2000–5000 mL large beakers are also available.
- Filling rule: keep the liquid volume at 1/2 to 2/3 of the beaker capacity to leave room for boiling and stirring.
- Graduation: beaker scales are rough (±5% typical); a 250 mL beaker divides at 25 mL intervals.
4. Usage Precautions
- Always heat on a wire gauze — never place the beaker directly on a flame or hotplate element; even heating prevents localized stress fractures.
- No thermal shock — cool hot beakers on a gauze; never plunge a hot beaker into cold water.
- Do not use beaker scales for quantitative work — use volumetric flasks, pipettes or measuring cylinders for exact volumes.
- Stir with a glass rod and pour along the rod to avoid splashing; avoid scratching the wall with metal tools.
- Alkali attacks glass — prolonged contact with concentrated alkali frosts the wall; use plastic (PP/PTFE) vessels for strong bases.
- Never use glass with HF — hydrofluoric acid dissolves glass; use PP or PTFE beakers.
5. FAQ
❓ Can a beaker be heated directly on a flame?
Borosilicate 3.3 beakers can be heated on an open flame or hotplate, but always on a wire gauze for even heating. Soda-lime beakers should not be flame-heated. Never thermally shock either type.
❓ Are beaker graduations accurate?
No. Beaker scales are for rough estimation only (±5% or worse). Use a measuring cylinder, volumetric flask or pipette whenever an exact volume matters.
❓ How do I tell borosilicate from soda-lime beakers?
Check three things: ① marking lines — borosilicate beakers typically carry 5 blue lines; ② markings — "3.3" or "BORO 3.3" printed on the wall; ③ weight and clarity — borosilicate is more transparent with uniform wall thickness, and noticeably pricier.
❓ Can beakers go in the microwave?
Borosilicate beakers can be microwaved briefly, but never heat sealed containers, never heat dry, and remove any metal (e.g. foil). Superheating can cause violent boiling — add a glass rod or boiling chips.
❓ Why has my beaker turned cloudy/frosted inside?
This is usually alkali etching (from concentrated NaOH/KOH) or glass devitrification from long-term heating. The glass becomes weaker — replace it rather than continuing to heat it.