At Queenswood school in the UK, David Boyce and his class are growing what they’re calling the world’s largest single crystal of copper sulfate, taking a classic school experiment to the next level.
While their crystal weighs in at around 3kg, the Guinness world record for the biggest copper sulfate crystal is still held by a class of 8th year students in Germany, who grew an enormous 70kg polycrystalline crystal in 2010.
But what other chemical classroom feats have received a Guinness World Record?
When life gives you lemons
Using a galvanised nail and a copper penny as electrodes and lemon juice as an electrolyte can create a rudimentary battery. When the zinc-coated nail is pushed into a lemon, the mild citric acid in the fruit oxidises the metal anode, releasing positively charged zinc ions into solution, while electrons flow through a wire to the copper cathode. At the cathode, oxygen from the air gains these electrons and, along with protons from the acid and electrons from the zinc, is reduced to water. Electrolytes in the lemon also play an important role as they neutralise the build-up of positive charge as zinc ions are released, allowing electricity to continue to flow.
Each lemon can generate around 1.5V and, in 2021, a team coordinated by the Royal Society of Chemistry created a record-breaking giant lemon battery using nearly 3000 lemons, producing over 2300V. However, with a current of just 0.9mA the giant lemon battery produced just 2W of power – not even enough to power a low-energy light bulb.
Power from potatoes
Potato batteries are another staple school experiment. Just like the lemon battery they can use zinc and copper electrodes and work in the same way, although they depend on phosphoric acid found in the tubers. The crisp company Lays set a record by connecting over 8500 potatoes together to generate 11W of power, using the electricity produced to record a song by Brazilian singer Anitta.
Pacey pipetting
Sujoy Kumar Mitra in India set the record for transferring the largest amount of water (45ml) via pipette in one minute in 2025. He is also the fastest person to visit all new seven wonders of the world, doing so in 5 days, 17 hours and 28 minutes.
Elephant’s toothpaste
Mixing hydrogen peroxide, washing up liquid and dried yeast, along with some food colouring, quickly creates vast amounts of ‘toothpaste’ foam. Yeast contains the enzyme catalase that rapidly breaks down hydrogen peroxide into water and oxygen, which then bubbles through the washing up liquid to create a foam. Such large quantities of foam are produced that the experiment has been nicknamed ‘elephant’s toothpaste’ – enough toothpaste foam to clean the teeth of an elephant.
The largest demonstration of the elephant’s toothpaste science demo to date was carried out by educational company KiwiCo in the US in 2022. The team produced 340m3 elephant toothpaste – about the same volume as a standard 25m long swimming pool.
There’s hydrogen and helium, then lithium, beryllium…
The periodic table song is helpful for chemistry students who want to learn all the elements. However, it’s not as quick as the 35.10 seconds that Prithvi Vangaveti in India took to recite all 118 elements in 2025, the fastest time recognised by Guinness World Records.
Chemistry World recreated Tom Lehrer’s original 1959 elements song in 2019 with the help of a local brass band. Another 16 elements were added to Lehrer’s song that have been synthesised since 1959. You may even be able to spot some cameos from some famous chemists, including Nobel prize winners.
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