Thinking and Working Scientifically & Laboratory Reference
Reference 2: Working Accurately, Safely & Using Scientific Instruments
5 min read 5 parts Lesson 8 of 8
Lesson summary
Reference 2: Working Accurately, Safely & Using Scientific Instruments — Alhussan International Academy — Science (Stages 7–9) notes: Use measuring instruments correctly, recognise hazard symbols and follow safe working rules.Instrument — measuring cylinders measure volumes of li…
- Calculate the mass of liquid
- Hot apparatus
- Glass apparatus
- Supporting apparatus
- Electrical circuits
- Place the measuring cylinder on a flat surface
Section 1 of 5Measuring volume with a measuring cylinder
- Instrument
- measuring cylinders measure volumes of liquids or solutions and are better than a beaker because they show smaller differences in volume.
- Place the measuring cylinder on a flat surface.
- Bend down so your eyes are level with the surface of the liquid.
- Read the volume from the scale, looking at the bottom of the curved surface, the meniscus.
- Units
- volume is measured in cubic centimetres (cm3) or millilitres (ml), and 1 cm3 equals 1 ml.
Section 2 of 5Measuring temperature with a thermometer
- Principle
- in an alcohol thermometer the liquid expands up the column when the bulb is in a hot liquid and contracts in a cold liquid.
- Look at the scale and work out the temperature difference for each small division.
- Place the bulb of the thermometer in the liquid.
- Bend down so your eyes are level with the liquid in the thermometer.
- Read the scale.
- Units
- most thermometers measure temperature in degrees Celsius, °C.
Section 3 of 5Measuring mass with a balance
- Instrument
- a balance measures mass, in grams (g) or kilograms (kg).
- Liquid in a container:
- Place the empty beaker on the pan and read its mass.
- Pour the liquid into the beaker and read the new mass.
- Calculate the mass of liquid (mass of beaker + liquid) − (mass of beaker).
Section 4 of 5Hazard symbols
- Hazard a possible danger linked to using substances or doing experiments, and hazardous substances show hazard symbols.
| Hazard | What it means | Reduce the risk by |
|---|---|---|
| Corrosive | The substance attacks and destroys living tissue, such as skin and eyes | Wearing eye protection and avoiding contact with the skin |
| Irritant | Not corrosive, but makes the skin go red or form blisters | Wearing eye protection and avoiding contact with the skin |
| Toxic | Can cause death, for example if swallowed or breathed in | Wearing eye protection and gloves, and wearing a mask or using a fume cupboard |
| Flammable | Catches fire easily | Wearing eye protection and keeping away from flames and sparks |
| Explosive | May explode if it comes into contact with a flame or heat | Wearing eye protection and keeping away from flames and sparks |
| Dangerous to the environment | May pollute the environment | Taking care with disposal |
Section 5 of 5Other hazards and safe working
- Hot apparatus
- take care not to touch it, even if it does not look hot.
- Glass apparatus
- take care not to break it, and leave it in a safe place on the table where it cannot roll off.
- Supporting apparatus
- support it safely, for example weigh down a clamp stand when hanging heavy loads from the clamp.
- Electrical circuits
- switch off before making any change, and remember that wires may get hot even at low voltage.
- Never connect wires across the terminals of a battery.
- Light
- do not look directly at the Sun or at a laser beam.
- Eyes
- wear eye protection whatever you are doing in the laboratory.
- Teacher
- always follow your teacher's safety advice as well, since the hazard table does not list every hazard.
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