Diffusion of iodine Bob Worley 2025-10-06 | A very simple activity to show the diffusion of iodine in a glass Petri dish
Nitrogen monoxide preparation and reactions Bob Worley 2025-09-05 | I did a similar video on youtube.com/watch?v=p_MUeIWe-ls&t=15s a year ago. The advantage of using this method of preparing nitrogen monoxide Is that the chemicals sodium nitrite , iron(II) sulfate -7-water, and 1 M sulfuric acid are safer to use. When 10 said to be the cube of oxygen is pushed into 20 cm3 of nitrogen monoxide there is no increase in volume. In fact, once added the volume decreases as brown nitrogen dioxide reacts to form colourless dinitrogen tetroxide.
A new method of vacuum filtering for school chemistry. Bob Worley 2025-08-02 | Gravity filtering through filter paper can take a long time. So here is a very quick, inexpensive vacuum method using syringes and a 3-way tap with a stopper.
The One-Penny Hofmann de luxe Bob Worley 2025-07-15 | This is single-use Hofmann electrolysis of water. This idea of using drawing pins as electrodes is touted as a "fun-practical" , but here is a version that allows you to collect and test gases, make explosions, and fire rockets. However, despite the production of green hydrogen, ethical issues regarding the use and disposal of plastic need to be discussed.
Watching a precipitate form on thermochromic plastic Bob Worley 2025-05-25 | You can see the video on just plastic at youtube.com/watch?v=HzsS7K7iQ7Y, but on thermochromic plastic, it provides so much more information, with endothermic and exothermic reactions taking place in a 1 cm³ diameter droplet of water.
One substance; three states of matter. Bob Worley 2025-05-03 | TBA (tertiary butyl alcohol, 2,2-dimethyl propanol) has some interesting properties. It melts at 26°C and boils at 82°C. So it is solid on cold days. So here I show 3 states of matter starting with 0.15 g of material.
Rotating electrolysis 2: Just awe and wonder to some quite complex chemistry and physics Bob Worley 2025-04-04 | I looked for a suitable +ve ion and found that the tetraamminecopper(II) ion works. One has to forego the observation of the LED gradually lighting up.
Rotating electrolysis 1: Just awe and wonder to some quite complex chemistry and physics Bob Worley 2025-04-02 | How are the movements of ions in water affected by both electrical and magnetic fields at the same time? It sounds complicated (and it is to a chemist), but it produces an amazing result which links with mass spectrometry and might just convince students and charged atoms and molecules (i.e. ions) really exist and have to be taught because they are all around us. I think we have to realise that electrolysis (an endothermic process ) is a consequence of the conductivity of electricity through water, using ions and not electrons. And ion-solvent dipole forces need to be taught at an early stage as an interparticle attraction.
The basis of carbon capture. Bob Worley 2025-03-16 | With so much concern about carbon dioxide levels in the atmosphere from burning fossil fuels and quicklime production, I try to demonstrate the carbon capture principle by applying sodium carbonate solution to carbon dioxide and then adding calcium hydroxide to separate calcium carbonate, which contains that carbon.
IronIII thiocyanate complex Bob Worley 2025-03-01 | Iron(III) nitate and potassium thiocynate are inserted into a puddle of deionized water from opposite ends. The solids dissolve, releasing solvated ions, which diffuse into the water. When the ions meet, the red complex forms. But if I bring a Nd magnet close by, the complex is distorted due to the unpaired electrons in the iron(III) ion. This is called paramagnetism
How acid rain forms Bob Worley 2025-02-09 | I know there is a similar video on this site, but here is a more up-to-date one. Seeing these reactions in a Petri dish using up to 50 cm³ of a very toxic gas is truly remarkable.
Oxidation of propanone: A Valantines Day demonstration Bob Worley 2024-09-18 | Hot clean copper foil is used to catalyse the oxidation of propanone to several products. As well as water and carbon dioxide, ethanal and ethenone (H2C=C=O) are made. It kept going until propanone had gone, nearly an hour.
Oxygen content of air using red phosphorus Bob Worley 2024-09-18 | This demonstration used to be carried out with white phosphorus. It is no longer available as it is difficult to transport and store. Red phosphorus is a more stable allotrope of the element and can be used if Ignited with a hot glass rod.
Advanced catalytic cracking Bob Worley 2024-08-20 | This advanced method uses plastic syringes to collect the gases over water. The gas is removed via a 3-way tap into smaller syringes for burning. It also shows how to do make bromine water in situ in a syringe to estimate the percentage conversion of double bonds.
Catalysis Bob Worley 2024-08-01 | This series of slides shows how catalysis can be studied using microscale methods on a plastic sheet. They work by altering the mechanism. This can be shown in how copper catalyses the metal/acid reactions by allowing electrons a more efficient route to reach the surface and react with acid ions to form hydrogen bubbles,
The reacion between nitrogen monoxide and oxygen. Bob Worley 2024-06-07 | Watch the addition of oxygen to nitrogen monoxide having no effect position of the barrel in a syringe. And then something remarkable happens as the nitrogen dioxide dimerizes is into dinitrogen tetroxide
The nitrogen dioxide/dinitrogen tetroxide dynamic equilibrium system Bob Worley 2024-05-28 | Chemical equilibrium is important but a very difficult concept to study and teach. This video shows a new way of making the gas in plastic syringes along with evidence of the influence of pressure and temperature on the system.
The Microelectrolysis of Sodium Chloride solution Bob Worley 2024-05-06 | This cell uses a small piece of mineral wool to act as a diaphragm which stops the hydroxide ions formed at the cathode from travelling to the anode where they would react with chorine gas and stop it being produced. Now a sodium-ion selective membrane is used but the effect is similar.
Electrolysis and explosion between hydrogen and oxygen Bob Worley 2024-04-25 | Using paper clips as electrodes, this video shows the electrolysis of water, containing sodium sulfate. in the bulb of a pipette. The liquid is coloured with a smidgeon of methyl red. hydrogen and oxygen is produced. A spark causes the explosion. This is a temporary video as the equipment is improved for general use. The remarkable yellow flash lasting as little as 1/250th of a second is beautiful.
The Explosive Reaction between Hydrogen and Oxygen: Eudiometry Bob Worley 2024-04-16 | Hydrogen oxygen explosions in a plastic pipette. A microscale eudiometer. Eudiometers were used in the 19th century to establish the formulas of gas molecules.
The reaction between sodium and chlorine Bob Worley 2024-03-25 | Making the syringe of chlorine should be carried out in a fume cupboard. The reaction can be carried out in a well-ventilated room as most of the chlorine is removed by the reaction. Chlorine affects the rubber seals in syringes so should be used as quickly as possible after collection. Thank you to Dr Michael Bauer in Gernany for permission to use the idea.
biodiesel video Bob Worley 2024-03-24 | Biodiesel was all the rage some years ago. There is a lot to it so sorry it s so long
Electrolysis of molten sodium chloride Bob Worley 2024-03-07 | This might be a first for many chemists because in 60 years of chemistry, I have never seen this but with modern electrical equipment (LED) improvisation and experience of the power of microscale techniques it seems to work. The sodium form is air oxidised so no sparks when added to water but the evidence is there.
Microscale chemistry triumphs Bob Worley 2024-01-30 | This was produced for the RSC when I won the RSC Prize ce in 2021. You will notice that the "wows" are different from the bangs flashes and smells (which can still be done) but you can som really beautiful presentations..
Making Esters of Butanol Bob Worley 2024-01-27 | Introducing a microscale heater by which relaxing and distillation
Hofmann voltameter movie Bob Worley 2024-01-19 | There are MANY activities you can carry out with my little Hofmann.
Detecting carbon dioxide and water when heating hydrocarbons and wood Bob Worley 2024-01-07 | The old rather rigid and underwhelming version using glass equipment whereby carbon dioxide and water are detected from burning wood and hydrocarbons is shown. Using syringes instead, the demo is now available for students to do and is relevant to curriculums highlighting climate change and sustainability.
Electrolysis of copper sulfate with fibre electrodes Bob Worley 2023-12-04 | Textbooks say oxygen is given off at the positive electrode, but the operating voltage has to increase to observe this. This is using a new design in electrolytic cells. To understand electrolysis, students should be familiar with solvated ions. The crucial inter-particle attraction is dipole-ion attraction. WE know this as the solvation of ions. it is not commonly taught but just as important as hydrogen bonding and dipole-dipole attractions.
Using the CLEAPSS electric heater Bob Worley 2023-11-29 | The heater is easily made and you find the method on youtu.be/UCzOD7EAXlkCLEAPSS subscribers can read about it on GL254 Make-it guide - microscale distillation apparatus.This opens up microscale organic chemistry to me. Do I enter the portal?
Rate of reaction: small-scale style Bob Worley 2023-11-11 | The reaction, between marble chips and dilute hydrochloric acid, takes place in syringes fitted with a 3-way tap and stopper. Two methods of measuring volume are shown. The solubility of carbon dioxide in water affects the values.
The ozone video Bob Worley 2023-09-23 | I hopefully improved on what I showed before. Ozone is a very important chemical as it is used in removing bacteria but is also important with regard to climate and atmospheric chemistry. The greater the operating voltage applied, the more ozone is present in the oxygen being produced at the anode in the electrolysis of water.
Testing for nitrates Bob Worley 2023-09-15 | We have no confirmatory test for nitrate ions in our exam schemes. Once we used Devardas alloy(Cu/Al) in boiling sodium hydroxide solution to reduce the nitrate ion to ammonia and this probably put people off. It is not required; aluminium foil works just as well and produces a beautiful halo,. Here is a microscale method to identify the ammonia coming off
Magnesium reacting with steam Bob Worley 2023-09-10 | This has been a popular demonstration for years but it often does not work One reason is the poor diagrams in the books. So here is the large version but could I use the same microscale equipment with this more violent reaction and also a microscale version. Yes, I could also use the ribbon and make it quantitative. The microscale has to add more than the traditional method.
Zinc and iron reacting with steam Bob Worley 2023-09-09 | The more active metals (potassium, sodium, and lithium) react with water. The less reactive metals react with steam. Here is zinc and (less active) iron reacting with steam
Calcium reacting with water; a quantitative approach Bob Worley 2023-09-02 | Using modern techniques with syringes and 3-way taps, here is a super way of collecting the hydrogen from a known mass of calcium
Two conservation-of-mass activities Bob Worley 2023-08-31 | There are 2 methods. First the precipitation of copper carbonate and second the reaction of calcium carbonate with hydrochloric acid. These are carried out on a balance costing less than £10 from online suppliers. It also uses the soda water bottle to retain gas. When the top is removed the heavy gas escapes or can be collected for a lime water test.
Raging Raisin and Singing Sultana Bob Worley 2023-08-18 | Here is an alternative to the Howling Jelly Baby. There is no concern about which colour sweet to use. There has been a qorry when teachers have used the word "cremation" as some students and teachers may have had these events occur recently in their families.
An alternative chemical test for water when hydrogen burns Bob Worley 2023-08-10 | Burning 50 ml of hydrogen from a syringe produces 0.04 g of water. This can be detected using ethanolic bromophenol blue,.
The Thermit reaction in a test tube Bob Worley 2023-06-09 | SSERC offers a similar service to schools in Scotland as CLEAPSS does in other parts of the UK. Chris Lloyd tells me this method is from Allen Cochrane, who was an exceptionally knowledgeable chemist, who I had great respect for.
Activity series of metals as EMF Bob Worley 2023-06-01 | Here is a simple method of seeing how the nature of different electrodes affects the generated EMF. I can even do this with lithium, sodium, and calcium (not shown). The chemical concepts in school usually follow rates of reaction (eg, metals with water), but this method looks at energy. differences between different metals
Electrolysis of copper(II) sulfate solution Bob Worley 2023-05-12 | Using microscale techniques, I am able to show oxygen does come off at the positive electrode (anode) when 1 M copper sulfate solution undergoes electrolysis.
pH changes in electrolysis Bob Worley 2023-05-12 | In the space of a couple of cemtimetres the concentration of hydrogen ions in this solution changes over 100,000,000,000,000 times.
Flame tests using a spirit burner Bob Worley 2023-04-21 | Dampen a pointed wooden spill, dip it into a salt, and then into the flame. It is surprising a spirit burner can be used instead of a Bunsen burner.
The Effect of Temperature on the N2O4 and NO2 equilibrium Bob Worley 2023-04-09 | This also shows you how to make a small permanent tube of the gas to show visually the effect of temperature on equilibrium. Must use borosilicate glass though, not soda glass
Generating a syringe full of hydrogen and burning it Bob Worley 2023-03-11 | Here is a quick and easy way to make hydrogen. It illustrates the concept of the limiting reagent as well. There are other interesting experiments on this channel. Watch youtube.com/watch?v=9jNhAT-fQvg&t=51s which shows how you can detect the existence of products other than water when burning hydrogen.Watch youtube.com/watch?v=a7aRGJ-Y6Ik which is what happens when you push different gases through a toy whistle.
The Aluminium/Bromine Reaction Bob Worley 2023-02-02 | Pure bromine is getting very expensive to buy and ship. But I used to do this regularly in the 80s. Aluminum bromide is an unusual substance because it breaks many so-called rules (there is covalent bonding between a metal and a non-metal.) I always maintain that if you know the exceptions, it is easier to know the rules they are breaking.
A Colourful Reaction in Dynamic Equilibrium Bob Worley 2023-02-01 | Cobalt chloride dissolves in propan-2-ol to form a deep blue solution. Drops of water are added to make an intermediate colour. Then it is moved from hot and cold water.
The small-scale decomposition of ammonium dichromate(VI) Bob Worley 2023-01-15 | Safety and environmental issues have curtailed the large scale versions but here is a contained version which should still be carried out in a fume cupboard. The surprise was that I could then investigate it quantitively.
Wobble a Puddle on a Nasturtian Leaf Bob Worley 2022-12-31 | When Nasturtians are availble, students can demonstrate the the effect on an electrostatic field on water seated at their desk. No need for a messy stream of water. Make the bulb of a plstic pipeete electrosttic by rubbing it on cltother materail and bring it close to the puddle.
