Substances Changing: Reaction on Heating
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 a reaction that takes place on heating to a higher temperature.
These resources cover the reaction between magnesium and oxygen. When heating magnesium in the open air the consumption of oxygen is not directly observable. Many students find the traditional experiment of monitoring mass changes difficult to interpret, especially if they think ‘gases’ such as oxygen have no mass. The approach here is novel, in that pure oxygen is held within a plastic bag attached to a test-tube containing magnesium. One video shows the bag collapsing as the magnesium reacts. The animations represent the changes of substances in terms of atoms and give practice at constructing a word equation. Other videos contrast heating magnesium and copper in the open air.
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.
HEALTH and SAFETY
Any use of a resource that includes a practical activity must include a risk assessment. Please note that collections may contain ARCHIVE resources, which were developed at a much earlier date. Since that time there have been significant changes in the rules and guidance affecting laboratory practical work. Further information is provided in our Health and Safety guidance.
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Resource by: Gatsby Science Enhancement Programme
Collections
The resource is part of Gatsby Science Enhancement Programme
- SEP: Matter and Change
- Stuff and Substance: Teachers' Resources
- Animations and Videos: Changing Substances
- Substances Changing: Reaction on Heating
CPD links
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How science works (stage 2)
Science Learning Centre East Midlands - William Farr School, Welton
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Secondary science subject leader conference - impact awards available
Science Learning Centre South West
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Essential science enrichment
National Science Learning Centre
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How science works - stage 2 - impact award
Science Learning Centre London
Comments
Yes, it is a real experiment - I shot the video (all of the videos in S&S are actual experiments, conducted in a 'normal' lab). The bag is full of pure oxygen (collected from decomposing hydrogen peroxide with manganese dioxide catalyst) - enough to react with all of the magnesium. However inside the test-tube is just air - that way there isn't much, if at all, reduction in the overall pressure inside the apparatus as the reaction proceeds. I also cleaned the surface of the magnesium ribbon - to make it look nicer but that might also have helped with the initial reaction. It might be worth checking your apparatus for 'air tightness' - any breaches and air will be drawn in rather than the bag collapsing - sometimes a hole develops in the test-tube as the glass softens during the reaction.
As noted by Anna, the expectation that you carry out your own risk assessment applies.
Hello,
Thank you for raising this. Although all the demonstrations on the package show results of actual experiments, they would not all be suitable to be carried out in a school setting. We appreciate that you will carry out your own risk assessment for any activity in school, but there is generic guidance on health and safety here http://www.nationalstemcentre.org.uk/elibrary/health-and-safety, which you may find useful.
Please can you tell us if this is a real experiment or just a 'set-up' for the video? We have tried it several times and cannot get any deflation of the bag, nor does our magnesium burn so brightly and we are left with ribbon with a coating of magnesium oxide- not a pile of powder!
Thanks