The right apparatus depends on the quantity you need, the precision the task asks for and the safety risk. Ask those three questions before you name anything.
This lesson is part of laboratory safety and investigation. The previous lesson, interpreting hazard symbols, covers the safety side of the choice.
How do I pick apparatus for a task?
Use this filter in order. Each question narrows the options.
- What quantity? Length, mass, volume, temperature, time or current each has its own instrument.
- How precise? A rough amount allows a beaker. A measured amount needs a scale with fine divisions.
- How safe? Heating, corrosive liquids and fragile glass change how you hold, heat or transfer the material.
Worked example: measuring a liquid for a test
A teacher asks a student to measure 25 cm³ of dilute acid for a reaction and then heat it gently.
Step 1: quantity. The quantity is volume, so the options are a beaker, a measuring cylinder or a pipette.
Step 2: precision. The teacher specifies 25 cm³, so a rough beaker mark is not enough. A measuring cylinder with small divisions fits.
Step 3: safety. The acid is corrosive and the task involves heating. Wear goggles, use a heat-resistant boiling tube or beaker, and heat with a water bath, not a direct flame, if the procedure allows.
The answer: a 25 cm³ measuring cylinder to measure the acid, then a heat-resistant container on a tripod and gauze.
Why a small-volume cylinder can beat a large one
Suppose a 100 cm³ cylinder has divisions of 1 cm³ and a 25 cm³ cylinder has divisions of 0.5 cm³. To measure 20 cm³, the smaller cylinder reads more precisely because its divisions are finer.
That is why the best choice is the smallest cylinder that can hold the volume you need.
The mistake that costs marks
The slip is to name an apparatus that can hold the substance but cannot measure it well enough. A beaker holds water, but it cannot give a measured volume.
| Task | Weak choice | Better choice and reason |
|---|---|---|
| Measure 30 cm³ of water | Beaker | Measuring cylinder, finer divisions |
| Find the mass of 5 g of salt | Ruler | Electronic balance, measures mass |
| Time a falling ball over 2 s | Wall clock | Stopwatch, reads to 0.1 s |
| Heat a small amount of solid | Plastic cup | Boiling tube, heat-resistant glass |
Every answer that earns the mark has three parts: the apparatus, the quantity, and a short reason.
Check yourself
A student wants to compare the temperature of a cup of warm water before and after 10 minutes. Name the apparatus, say what quantity it measures, and give one reason why it suits the task.
Answer
A thermometer, because the quantity is temperature. A laboratory thermometer with 1 °C divisions suits this task because the temperature change is likely to be at least 3 °C.
The student should also use a stopwatch to time the 10 minutes, because the time interval must be the same in each test.
What to study next
After choosing apparatus, you must read it accurately. Continue with reading measurements and reporting units, then try the practice set.
To talk through your own practical tasks with a teacher, see online one-to-one Science tuition.