Reading Instruments with Significant Figures Worksheet displaying measurements from different lab equipment with correct units and significant figures.
Worksheet showing various scientific instruments including balances, rulers, thermometers, graduated cylinders, and pressure gauges with readings and significant figures indicated.
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The image you've uploaded is a "Reading Instruments with Significant Figures Worksheet" that includes various laboratory instruments (such as balances, rulers, thermometers, graduated cylinders, and pressure gauges), each with a reading to be interpreted. The worksheet also provides the correct answers and the number of significant figures for each measurement.
Let’s go through each instrument systematically, explain how to read it, and verify the provided answers based on proper significant figure rules.
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- Instrument: Triple beam balance
- Reading:
- 500 g + 70 g + 7.66 g = 577.66 g
- Significant Figures: All digits are significant → 5 SigFigs
✔ Answer: 577.66 g (5 SigFigs) — Correct
> *Explanation:* The rider on the smallest beam is between 7.6 and 7.7, so we estimate to 7.66 g. Since all digits are measured, including the estimated digit, this gives five significant figures.
---
- Reading:
- 400 g + 90 g + 8.92 g = 498.92 g
- Significant Figures: All digits are significant → 5 SigFigs
✔ Answer: 498.92 g (5 SigFigs) — Correct
> *Explanation:* The smallest scale allows estimation to 0.01 g, so the last digit is an estimate.
---
- Measurement: From 3 cm to 7.70 cm
- Reading: 7.70 cm
- Significant Figures: 3 SigFigs (7, 7, and 0 — trailing zero after decimal is significant)
✔ Answer: 7.70 cm (3 SigFigs) — Correct
> *Explanation:* The ruler has millimeter markings; we can estimate one decimal place beyond the smallest division (tenths of a cm). The object ends just past 7.7 cm, so 7.70 cm is appropriate.
---
- Measurement: From 0 to 1.00 cm
- Reading: 1.00 cm
- Significant Figures: 3 SigFigs (all digits are significant)
✔ Answer: 1.00 cm (3 SigFigs) — Correct
> *Explanation:* The ruler has millimeter marks, so we can estimate to 0.01 cm. The object ends exactly at the 1.00 cm mark.
---
- Scale: 10 mL per major division, subdivided into 10 → 1 mL per small division
- Meniscus level: Between 30 and 40 mL, closer to 31.7 mL
- Reading: 31.7 mL
- Significant Figures: 3 SigFigs
✔ Answer: 31.7 mL (3 SigFigs) — Correct
> *Explanation:* We estimate one decimal place beyond the smallest division (0.1 mL). The meniscus is at ~31.7 mL.
---
- Scale: 5 mL per major division, subdivided into 5 → 1 mL per small division
- Meniscus: Between 20 and 25 mL, at 21.3 mL
- Reading: 21.3 mL
- Significant Figures: 3 SigFigs
✔ Answer: 21.3 mL (3 SigFigs) — Correct
---
- Scale: 5 mL per major division, subdivided into 5 → 1 mL per small division
- Meniscus: At 18.5 mL (midway between 18 and 19)
- Reading: 18.50 mL? Wait — but only one decimal place is readable?
- Wait: The cylinder shows 18.5 mL, but the answer says 18.50 mL (4 SigFigs)
🛑 Issue: This seems incorrect.
- If the smallest division is 1 mL, we can estimate to ±0.1 mL.
- So, reading should be 18.5 mL, not 18.50 mL (which implies precision to 0.01 mL).
- Correct Answer: 18.5 mL (3 SigFigs)
✘ Provided Answer: 18.50 mL (4 SigFigs) — ✘ Incorrect
> *Correction:* Unless the cylinder has subdivisions of 0.1 mL, you cannot report two decimal places.
But wait — looking closely, the scale goes from 10 to 20 with 10 subdivisions, so each division is 0.5 mL? Let's recheck:
- From 10 to 20: 10 divisions → each = 1 mL
- So, yes, smallest division = 1 mL → estimate to 0.1 mL
- Therefore, reading should be 18.5 mL, not 18.50 mL
✔ Corrected Answer: 18.5 mL (3 SigFigs)
---
- Scale: 1 mL per division (from 1 to 5 mL)
- Meniscus: At 3.2 mL (between 3 and 4)
- Estimate: 3.21 mL? But the smallest division is 1 mL → can only estimate to 0.1 mL
- Reading: 3.2 mL → but answer says 3.21 mL (3 SigFigs)
🛑 Issue: Again, overestimation.
- With 1 mL divisions, we can estimate to 0.1 mL, so 3.2 mL is best.
- But if there are 0.1 mL subdivisions, then 3.21 mL could be valid.
Looking at the diagram:
- It shows 1 mL divisions (labeled 1, 2, 3, 4, 5)
- No smaller ticks → so no 0.1 mL subdivisions
→ Cannot read to 0.01 mL
✘ Provided Answer: 3.21 mL (3 SigFigs) — ✘ Incorrect
✔ Correct Answer: 3.2 mL (2 SigFigs)
> *Note:* Some interpretations might allow estimating halfway, but 3.2 mL is acceptable.
---
- Scale: 10 mL per division, subdivided into 10 → 1 mL per tick
- Meniscus: Just below 51 mL → 50.9 mL
- Significant Figures: 3 SigFigs
✔ Answer: 50.9 mL (3 SigFigs) — Correct
> *Explanation:* Estimate to 0.1 mL, which is valid here.
---
- Scale: 10 mL per division, subdivided into 10 → 1 mL per tick
- Meniscus: At 74.5 mL
- Significant Figures: 3 SigFigs
✔ Answer: 74.5 mL (3 SigFigs) — Correct
---
- Scale: 10°C per major division, subdivided into 10 → 1°C per tick
- Mercury level: At 38°C
- Estimated digit: Can estimate to 0.1°C
- Reading: 38.0°C
- Significant Figures: 3 SigFigs
✔ Answer: 38.0°C (3 SigFigs) — Correct
---
- Scale: Same as above
- Level: At 24°C
- Estimated: 24.0°C
- SigFigs: 3
✔ Answer: 24.0°C (3 SigFigs) — Correct
---
- Scale: Same
- Level: Below 0°C, at -26°C
- Estimated: -26.0°C
- SigFigs: 3
✔ Answer: -26.0°C (3 SigFigs) — Correct
---
- Scale: 0 to 120 kPa, in increments of 10 kPa
- Subdivisions: 10 between 0–10 → 1 kPa per tick
- Pointer: Between 70 and 80, closer to 70.9
- Reading: 70.9 kPa? But answer says 70.9 kPa (3 SigFigs)
Wait — the gauge shows 70.9 kPa?
But let’s check:
- Dials usually have 10 divisions between 0–10 → 1 kPa per tick
- Pointer is at 70.9 kPa → yes, possible
- SigFigs: 3 (7, 0, 9)
✔ Answer: 70.9 kPa (3 SigFigs) — Correct
---
- Scale: 0 to 120 psi, 10 divisions per 20 → 2 psi per tick
- Pointer: At 20 psi
- Can we estimate? Yes, to nearest 1 psi
- Reading: 20 psi → but answer says 2.0 kPa
Wait — units mismatch!
The gauge is labeled psi, but answer says 2.0 kPa
🛑 Major Error
- 20 psi ≈ 138 kPa → not 2.0 kPa
- Also, the pointer is pointing to 20 psi, not 2.0 kPa
✘ Answer: 2.0 kPa (2 SigFigs) — ✘ Incorrect
✔ Correct Answer: 20 psi (2 SigFigs) or convert to kPa: 138 kPa (3 SigFigs)
But since the label is psi, answer should be in psi.
So the correct answer is 20 psi (2 SigFigs)
> *Conclusion:* The provided answer is wrong in both unit and value.
---
- Scale: Millimeter markings
- Object starts at 79.0 mm, ends at 87.40 mm
- Reading: 87.40 mm
- SigFigs: 4 (all digits significant)
✔ Answer: 87.40 mm (4 SigFigs) — Correct
> *Explanation:* Ruler has mm markings, so we can estimate to 0.1 mm → 87.40 mm is correct.
---
- Object starts at 41.0 mm, ends at 47.00 mm
- Reading: 47.00 mm
- SigFigs: 4
✔ Answer: 47.00 mm (4 SigFigs) — Correct
> *Explanation:* Measured to 0.01 mm by estimation.
---
## ✔ Final Summary: Corrections Needed
| Instrument | Provided Answer | Correct Answer | Reason |
|----------|------------------|----------------|--------|
| Graduated Cylinder (18.50 mL) | 18.50 mL (4 SigFigs) | 18.5 mL (3 SigFigs) | Only 1 mL divisions → can't read to 0.01 mL |
| Small Graduated Cylinder | 3.21 mL (3 SigFigs) | 3.2 mL (2 SigFigs) | No 0.1 mL marks → can't estimate to 0.01 mL |
| Pressure Gauge (psi) | 2.0 kPa (2 SigFigs) | 20 psi (2 SigFigs) | Unit error and value wrong |
---
## 📝 Conclusion
Most of the answers on the worksheet are correct, but three are incorrect due to:
1. Overestimating precision (reading too many decimal places)
2. Incorrect unit conversion
3. Misreading the scale
- 18.5 mL (3 SigFigs) instead of 18.50 mL
- 3.2 mL (2 SigFigs) instead of 3.21 mL
- 20 psi (2 SigFigs) instead of 2.0 kPa
These corrections reflect proper use of significant figures and instrument resolution.
Let me know if you'd like a printable version with corrected answers!
Let’s go through each instrument systematically, explain how to read it, and verify the provided answers based on proper significant figure rules.
---
🔍 1. Triple Beam Balance (Top Left)
- Instrument: Triple beam balance
- Reading:
- 500 g + 70 g + 7.66 g = 577.66 g
- Significant Figures: All digits are significant → 5 SigFigs
✔ Answer: 577.66 g (5 SigFigs) — Correct
> *Explanation:* The rider on the smallest beam is between 7.6 and 7.7, so we estimate to 7.66 g. Since all digits are measured, including the estimated digit, this gives five significant figures.
---
🔍 2. Triple Beam Balance (Top Right)
- Reading:
- 400 g + 90 g + 8.92 g = 498.92 g
- Significant Figures: All digits are significant → 5 SigFigs
✔ Answer: 498.92 g (5 SigFigs) — Correct
> *Explanation:* The smallest scale allows estimation to 0.01 g, so the last digit is an estimate.
---
🔍 3. Ruler (Middle Left – Top)
- Measurement: From 3 cm to 7.70 cm
- Reading: 7.70 cm
- Significant Figures: 3 SigFigs (7, 7, and 0 — trailing zero after decimal is significant)
✔ Answer: 7.70 cm (3 SigFigs) — Correct
> *Explanation:* The ruler has millimeter markings; we can estimate one decimal place beyond the smallest division (tenths of a cm). The object ends just past 7.7 cm, so 7.70 cm is appropriate.
---
🔍 4. Ruler (Middle Left – Bottom)
- Measurement: From 0 to 1.00 cm
- Reading: 1.00 cm
- Significant Figures: 3 SigFigs (all digits are significant)
✔ Answer: 1.00 cm (3 SigFigs) — Correct
> *Explanation:* The ruler has millimeter marks, so we can estimate to 0.01 cm. The object ends exactly at the 1.00 cm mark.
---
🔍 5. Graduated Cylinder (Middle Right – First)
- Scale: 10 mL per major division, subdivided into 10 → 1 mL per small division
- Meniscus level: Between 30 and 40 mL, closer to 31.7 mL
- Reading: 31.7 mL
- Significant Figures: 3 SigFigs
✔ Answer: 31.7 mL (3 SigFigs) — Correct
> *Explanation:* We estimate one decimal place beyond the smallest division (0.1 mL). The meniscus is at ~31.7 mL.
---
🔍 6. Graduated Cylinder (Second)
- Scale: 5 mL per major division, subdivided into 5 → 1 mL per small division
- Meniscus: Between 20 and 25 mL, at 21.3 mL
- Reading: 21.3 mL
- Significant Figures: 3 SigFigs
✔ Answer: 21.3 mL (3 SigFigs) — Correct
---
🔍 7. Graduated Cylinder (Third)
- Scale: 5 mL per major division, subdivided into 5 → 1 mL per small division
- Meniscus: At 18.5 mL (midway between 18 and 19)
- Reading: 18.50 mL? Wait — but only one decimal place is readable?
- Wait: The cylinder shows 18.5 mL, but the answer says 18.50 mL (4 SigFigs)
🛑 Issue: This seems incorrect.
- If the smallest division is 1 mL, we can estimate to ±0.1 mL.
- So, reading should be 18.5 mL, not 18.50 mL (which implies precision to 0.01 mL).
- Correct Answer: 18.5 mL (3 SigFigs)
✘ Provided Answer: 18.50 mL (4 SigFigs) — ✘ Incorrect
> *Correction:* Unless the cylinder has subdivisions of 0.1 mL, you cannot report two decimal places.
But wait — looking closely, the scale goes from 10 to 20 with 10 subdivisions, so each division is 0.5 mL? Let's recheck:
- From 10 to 20: 10 divisions → each = 1 mL
- So, yes, smallest division = 1 mL → estimate to 0.1 mL
- Therefore, reading should be 18.5 mL, not 18.50 mL
✔ Corrected Answer: 18.5 mL (3 SigFigs)
---
🔍 8. Small Graduated Cylinder (Below)
- Scale: 1 mL per division (from 1 to 5 mL)
- Meniscus: At 3.2 mL (between 3 and 4)
- Estimate: 3.21 mL? But the smallest division is 1 mL → can only estimate to 0.1 mL
- Reading: 3.2 mL → but answer says 3.21 mL (3 SigFigs)
🛑 Issue: Again, overestimation.
- With 1 mL divisions, we can estimate to 0.1 mL, so 3.2 mL is best.
- But if there are 0.1 mL subdivisions, then 3.21 mL could be valid.
Looking at the diagram:
- It shows 1 mL divisions (labeled 1, 2, 3, 4, 5)
- No smaller ticks → so no 0.1 mL subdivisions
→ Cannot read to 0.01 mL
✘ Provided Answer: 3.21 mL (3 SigFigs) — ✘ Incorrect
✔ Correct Answer: 3.2 mL (2 SigFigs)
> *Note:* Some interpretations might allow estimating halfway, but 3.2 mL is acceptable.
---
🔍 9. Graduated Cylinder (50–60 mL)
- Scale: 10 mL per division, subdivided into 10 → 1 mL per tick
- Meniscus: Just below 51 mL → 50.9 mL
- Significant Figures: 3 SigFigs
✔ Answer: 50.9 mL (3 SigFigs) — Correct
> *Explanation:* Estimate to 0.1 mL, which is valid here.
---
🔍 10. Graduated Cylinder (70–80 mL)
- Scale: 10 mL per division, subdivided into 10 → 1 mL per tick
- Meniscus: At 74.5 mL
- Significant Figures: 3 SigFigs
✔ Answer: 74.5 mL (3 SigFigs) — Correct
---
🔍 11. Thermometer (Left)
- Scale: 10°C per major division, subdivided into 10 → 1°C per tick
- Mercury level: At 38°C
- Estimated digit: Can estimate to 0.1°C
- Reading: 38.0°C
- Significant Figures: 3 SigFigs
✔ Answer: 38.0°C (3 SigFigs) — Correct
---
🔍 12. Thermometer (Middle)
- Scale: Same as above
- Level: At 24°C
- Estimated: 24.0°C
- SigFigs: 3
✔ Answer: 24.0°C (3 SigFigs) — Correct
---
🔍 13. Thermometer (Right)
- Scale: Same
- Level: Below 0°C, at -26°C
- Estimated: -26.0°C
- SigFigs: 3
✔ Answer: -26.0°C (3 SigFigs) — Correct
---
🔍 14. Pressure Gauge (kPa)
- Scale: 0 to 120 kPa, in increments of 10 kPa
- Subdivisions: 10 between 0–10 → 1 kPa per tick
- Pointer: Between 70 and 80, closer to 70.9
- Reading: 70.9 kPa? But answer says 70.9 kPa (3 SigFigs)
Wait — the gauge shows 70.9 kPa?
But let’s check:
- Dials usually have 10 divisions between 0–10 → 1 kPa per tick
- Pointer is at 70.9 kPa → yes, possible
- SigFigs: 3 (7, 0, 9)
✔ Answer: 70.9 kPa (3 SigFigs) — Correct
---
🔍 15. Pressure Gauge (psi)
- Scale: 0 to 120 psi, 10 divisions per 20 → 2 psi per tick
- Pointer: At 20 psi
- Can we estimate? Yes, to nearest 1 psi
- Reading: 20 psi → but answer says 2.0 kPa
Wait — units mismatch!
The gauge is labeled psi, but answer says 2.0 kPa
🛑 Major Error
- 20 psi ≈ 138 kPa → not 2.0 kPa
- Also, the pointer is pointing to 20 psi, not 2.0 kPa
✘ Answer: 2.0 kPa (2 SigFigs) — ✘ Incorrect
✔ Correct Answer: 20 psi (2 SigFigs) or convert to kPa: 138 kPa (3 SigFigs)
But since the label is psi, answer should be in psi.
So the correct answer is 20 psi (2 SigFigs)
> *Conclusion:* The provided answer is wrong in both unit and value.
---
🔍 16. Ruler (Bottom – Long)
- Scale: Millimeter markings
- Object starts at 79.0 mm, ends at 87.40 mm
- Reading: 87.40 mm
- SigFigs: 4 (all digits significant)
✔ Answer: 87.40 mm (4 SigFigs) — Correct
> *Explanation:* Ruler has mm markings, so we can estimate to 0.1 mm → 87.40 mm is correct.
---
🔍 17. Ruler (Bottom – Short)
- Object starts at 41.0 mm, ends at 47.00 mm
- Reading: 47.00 mm
- SigFigs: 4
✔ Answer: 47.00 mm (4 SigFigs) — Correct
> *Explanation:* Measured to 0.01 mm by estimation.
---
## ✔ Final Summary: Corrections Needed
| Instrument | Provided Answer | Correct Answer | Reason |
|----------|------------------|----------------|--------|
| Graduated Cylinder (18.50 mL) | 18.50 mL (4 SigFigs) | 18.5 mL (3 SigFigs) | Only 1 mL divisions → can't read to 0.01 mL |
| Small Graduated Cylinder | 3.21 mL (3 SigFigs) | 3.2 mL (2 SigFigs) | No 0.1 mL marks → can't estimate to 0.01 mL |
| Pressure Gauge (psi) | 2.0 kPa (2 SigFigs) | 20 psi (2 SigFigs) | Unit error and value wrong |
---
## 📝 Conclusion
Most of the answers on the worksheet are correct, but three are incorrect due to:
1. Overestimating precision (reading too many decimal places)
2. Incorrect unit conversion
3. Misreading the scale
✔ Corrected Answers:
- 18.5 mL (3 SigFigs) instead of 18.50 mL
- 3.2 mL (2 SigFigs) instead of 3.21 mL
- 20 psi (2 SigFigs) instead of 2.0 kPa
These corrections reflect proper use of significant figures and instrument resolution.
Let me know if you'd like a printable version with corrected answers!
Parent Tip: Review the logic above to help your child master the concept of significant figures worksheet.
