EXPERIMENT GUIDES
Pick one. Book a bench. Run it.
Full protocols with apparatus lists, step-by-step technique, safety notes, and the results you should expect — so you know when you've nailed it.
19 of 19 experiments
Titration: ethanoic acid vs sodium hydroxide
The classic weak acid–strong base titration. Standardise 0.1 M ethanoic acid against 0.1 M NaOH using phenolphthalein, and see why the endpoint lands above pH 7.
Flame tests: identifying metal ions
Dip, flame, identify. Use the colours metal ions give a Bunsen flame to identify unknown salts — the same physics that puts colour in fireworks.
Food tests: starch, sugars, protein and fat
Four classic bench tests — iodine, Benedict's, biuret and the emulsion test — run on real food samples to detect the major nutrients.
Microscopy: onion epidermal cells
Prepare a wet mount of onion epidermis, stain it with iodine, and draw what you actually see at ×40 and ×400 — cell walls, nuclei and all.
Ohm's law: V–I characteristics of a resistor
Build the classic ammeter-voltmeter circuit, vary the current with a rheostat, and show that V/I is constant for a fixed resistor at constant temperature.
Simple pendulum: measuring g
Time a swinging pendulum at five lengths, plot T² against L, and extract the acceleration due to gravity from the gradient. Expect within 2% of 9.81 m/s².
Double-indicator titration: phosphoric acid against sodium hydroxide
Phosphoric acid holds three protons and gives up the first two at clearly separate points. Put two indicators in one flask and catch both end-points in a single run — red to orange, then yellow to green.
Qualitative analysis: identifying the ions in two unknown solids
Two labelled solids, a rack of reagents and no answers. Work through the standard test series, record what you actually see, and name the ions from the evidence.
Dye uptake in celery: does warmer water speed up the xylem stream?
Stand a dyed celery stalk in ice-cold water and its twin in warm water, then cut both into 5 mm cross-sections to see how far the dye actually travelled — and why warmth wins.
Moments: finding the weight of an unknown mass
Balance a metre ruler pivoted at its centre against an unmarked mass Q, using a 2.0 N load and then a 3.0 N load, and use the principle of moments to find Q's weight two independent ways.
Resistance of a wire: R depends on length (slide-wire method)
Tape ~105 cm of bare constantan wire to a metre rule, slide a contact along it to vary the length between a fixed terminal and the contact, and show that resistance is directly proportional to length.
Refraction through a rectangular glass block
Trace a ray of light into a rectangular glass block with optics pins, sight through the far side to find where it emerges, and show the emergent ray is parallel to the incident ray — displaced sideways, but travelling in the same direction. Measure the angle to confirm it equals the original angle of incidence.
Redox titration: ethanedioic acid vs potassium manganate(VII)
A self-indicating redox titration. Heat ethanedioic acid (oxalic acid) with dilute sulfuric acid to about 70°C, then titrate against acidified potassium manganate(VII) — no indicator needed, because KMnO4 is its own: the flask stays colourless until the very last drop leaves it permanently pale pink.
Thermal decomposition: water of crystallisation in hydrated zinc sulfate
Heat hydrated zinc sulfate, FA 4 (ZnSO₄·yH₂O), in a crucible until its mass stops changing, then use the mass of water driven off to calculate y — the number of water molecules per formula unit.
Qualitative analysis: a mislabelled salt and three manganese oxidation states
A bottle labelled hydrated zinc sulfate that isn't, and three manganese compounds that turn out to be the same element at different oxidation states. Devise your own cation/anion tests on the first, then run a fixed three-test comparison across the second.
Iodine clock: estimating hydrogen peroxide concentration by serial dilution
Serially dilute a 2.0% hydrogen peroxide stock by half, four times, then time how long each dilution takes to turn a starch–iodide–thiosulfate mixture blue-black. Use the same timing method on an unknown 'patient sample' to estimate its hydrogen peroxide concentration by interpolation.
Microscopy and stereology: a plant stem cross-section (slide J1)
A fixed, confidential, pre-mounted stem section — not one you prepare yourself. Draw a large low-power plan (labelling the xylem) and a high-power group of four epidermal cells (labelling the waxy cuticle), compare the slide against a printed photomicrograph of a different stem, then use a sector count and a known angle to estimate the section's vascular-bundle density.
Spring oscillations: series vs parallel stiffness
Hang a mass from two expendable springs — first in series as one 'double spring', then in parallel — and time the vertical oscillation period in each. Repeat across five masses and plot √T2 against √T1: the straight line through the origin reveals how series and parallel springs trade off stiffness.
Deformation of paper cylinders: testing w = k(y − p)
Roll a strip of paper into a cylinder and stand it under a spring-loaded 100 g mass. Squash it by a fixed amount and read how much the springs 'give back' — then test whether a wider strip needs proportionally more give, via w = k(y − p).