Teaching idea – changing state
Ask students if it is possible to turn hydrogen gas into a solid? If so, what would they have to do to it? Students could be given a particle diagram of a gas and a solid to help them explain.
Scientists have been trying for years to turn hydrogen into solid metallic hydrogen. Two scientists have put hydrogen under very high pressure and claim to have produced a very small amount of metallic hydrogen. To hear one of the scientists, Isaac Silvera talking about their work follow the link BBC 'Science in action' (first 7 minutes). (Or for the news article go to BBC news).
There is some controversy as to whether their claims are correct - this leads to a good opportunity to discuss with students the peer review process that is followed before work is accepted.
Further teaching resources can be found in the section 'Solids, liquids and gases' (KS3)