These resources have been reviewed and selected by STEM Learning’s team of education specialists for factual accuracy and relevance to teaching STEM subjects in UK schools.

Substances Changing: Reaction at Room Temperature

These downloadable videos and animations are part of the multimedia package Stuff and Substance, developed by the Gatsby Science Enhancement Programme (SEP). They can be used to develop the idea of chemical change by showing reactions that take place spontaneously at room temperature.

These resources use novel approaches to cover two commonly taught reactions. For ammonia reacting with hydrogen chloride, the two ‘gases’ are held in plastic bags which are seen to deflate as ammonium chloride emerges in the solid state. Calcium is reacted with a small amount of water so the emerging calcium hydroxide powder is obvious as well as the hydrogen (collected in a plastic bag). The videos show both reactions, and the animations represent the changes of substances in terms of atoms. A further video shows the reaction of calcium with excess water where the emerging calcium hydroxide dissolves and is not visible.

These video and animation files form part of the resources in the section Substances Changing in the Stuff and Substance multimedia package, which provides a series of interactive pages that can be used by teachers or students in the classroom.

Please note: From 2021, Adobe has discontinued support for Flash player and as a result some interactive files may no longer be playable. As an alternative method to accessing these files a group of volunteers passionate about the preservation of internet history have created project Ruffle ( Ruffle is an entirely open source project that you can download and run many interactive Flash resources. For further information regarding STEM Learning’s policy for website content, please visit our terms and conditions page.

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Please be aware that resources have been published on the website in the form that they were originally supplied. This means that procedures reflect general practice and standards applicable at the time resources were produced and cannot be assumed to be acceptable today. Website users are fully responsible for ensuring that any activity, including practical work, which they carry out is in accordance with current regulations related to health and safety and that an appropriate risk assessment has been carried out.

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