Curated Video
Ferrofluids
We compare the properties of three iron mixtures: iron and water, iron and oil and a ferrofluid - a mixture of compounds containing iron and oil. First, we look at how iron filings behave when mixed with water and then oil. We then hold...
Curated Video
Kiwi Fruit DNA
We extract the DNA from a kiwi fruit by mashing it with detergent liquid, salt and water. The mixture is then filtered and incubated before a layer of chilled ethanol is added. The jelly-like DNA can then be extracted. Biology - Cells...
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Stomach Acid and Antacid
We use the enzyme pepsin and hydrochloric acid to simulate the conditions within the stomach in two boiling tubes. Cooked egg whites are ground and added to two boiling tubes of hydrochloric acid, but one is mixed with a crushed antacid...
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Anaerobic Respiration: Observing Yeast's Oxygen-Free Energy Production
We use yeast to let us observe anaerobic respiration. The yeast is added to warm water and glucose. A layer of oil is placed over the solution so that no oxygen is available. The solution starts to bubble and the gas produced passes...
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Metal Extraction
We extract copper metal from copper chloride solution using electrolysis. The electric current causes copper to form at one electrode and chlorine gas to form at the other. The presence of chlorine is tested using blue litmus paper....
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Enzyme Action: Trypsin
We demonstrate denaturing by adding the enzyme trypsin to photographic film. Strips of photographic film are added to trypsin solution at different temperatures to determine the optimum conditions for the enzyme. In the right conditions...
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Chemical Filtration
We look at how chemical filtration can be used to remove contaminants from water. Potassium permanganate is used as the contaminant. First, we try to remove it using physical filtration, with filter paper and a funnel. This does not...
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Iron and Luminol
We use potassium ferricyanide and luminol indicator to show how forensic scientists detect blood at crime scenes. The luminol indicator contains luminol, sodium hydroxide and hydrogen peroxide. When luminol comes into contact with the...
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Oscillating Colour Change
We use three chemical solutions to create an oscillating reaction. The three different solutions are mixed using a magnetic stirrer and the colour changes from clear to amber to dark blue. This pattern repeats as the concentrations of...
Curated Video
Acidification of Water
We use a drinking straw, some water and universal indicator to show that breathing out creates acid. Universal indicator is added to the water to show its pH value. When we blow into the water the indicator changes colour showing that...
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Orange Tornado
We use mercury(II) chloride solution and potassium iodide to demonstrate a precipitation reaction. Saturated potassium iodide solution is placed on a magnetic stirrer and the speed is set so that a vortex is created. Mercury(II) chloride...
Curated Video
Ion Migration
We separate the ions in copper dichromate gel using electrolysis. We see the positive blue copper ions move to the negative electrode and the negative yellow chromate ions move to the positive electrode. Chemistry - Reactions - Learning...
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Silver Tree
We demonstrate a displacement reaction using silver nitrate and copper. A tree-shaped piece of copper is submerged in silver nitrate solution. The silver ions displace the copper and the tree slowly becomes coated with silver metal. At...
Curated Video
Meanders and Oxbow Lakes
Meanders and oxbow lakes are found in the middle course of a river. Discover how a meander forms and how this process can lead to an oxbow lake. Earth Science - Geology - Learning Points. At its middle course, a river gathers water...
Curated Video
Diophantine Equations: Fermat
This amateur mathematician proposed an exciting theorem that stood unproved for over three centuries. He claimed he had the proof – but no room to write it in the margin of his book. Maths - History Of Maths A Twig Math Film. Reinforce...
Curated Video
Salt: Separating Mixtures
Salt is found in the oceans and Earth's surface. How do we collect this salt and separate it from the materials it is mixed with? Chemistry - Atoms And Bonding - Learning Points. Salt is found in oceans, lakes and underground rock beds....
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Salt: Salt and Ice
Salt is routinely used to melt snow and ice on winter roads. But what is happening at the molecular level to cause this helpful change of state? Chemistry - Atoms And Bonding - Learning Points. When salt is added to water it lowers the...
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Buffer
A substance that maintains a solution in a narrow range of pH. A Twig Science Glossary Film. Key scientific terms defined in just 60 seconds using stunning images and concise textual definitions. Twig Science Glossary Films reinforce...
Curated Video
Neutral
In between two extremes, neither one thing nor another. A Twig Science Glossary Film. Key scientific terms defined in just 60 seconds using stunning images and concise textual definitions. Twig Science Glossary Films reinforce abstract...
Curated Video
Nucleation
The beginning of physical or chemical changes on a very small scale in discrete regions of a system. A Twig Science Glossary Film. Key scientific terms defined in just 60 seconds using stunning images and concise textual definitions....
Curated Video
The wonder of water
We use water every day ... but what do you really know about it? Material processes - Solids, liquids and gases - Characteristics of water Learning Points Water is the only substance on Earth that occurs naturally in all three states....
Curated Video
Condensation and freezing
Why do water drops form on cold windows and why does water freeze? Material processes - Solids, liquids and gases - Changes of state Learning Points Condensation is the change of state from gas to liquid. Freezing is the change of state...
Curated Video
Advanced separation
Find out how advanced separation processes are used to separate substances in complex mixtures. Material processes - Separating mixtures - Other means of separation Learning Points Chromatography separates pigments in a liquid....
Curated Video
Very strange liquids
Not all liquids act the same ... some can behave very strangely indeed! Material processes - Solids, liquids and gases - Liquids Learning Points Liquids do not have a fixed shape. Non-Newtonian liquids change behaviour when a force is...