Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; plgContentJComments has a deprecated constructor in /var/www/astarmathsandphysics/plugins/content/jcomments/jcomments.php on line 25 Call Stack: 0.0001 362552 1. {main}() /var/www/astarmathsandphysics/index.php:0 0.0947 1213448 2. Joomla\CMS\Application\SiteApplication->execute() /var/www/astarmathsandphysics/index.php:49 0.0947 1213448 3. Joomla\CMS\Application\SiteApplication->doExecute() /var/www/astarmathsandphysics/libraries/src/Application/CMSApplication.php:267 0.1736 4112752 4. Joomla\CMS\Application\SiteApplication->dispatch() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:233 0.1753 4140480 5. Joomla\CMS\Component\ComponentHelper::renderComponent() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:194 0.1761 4158192 6. Joomla\CMS\Component\ComponentHelper::executeComponent() /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:356 0.1761 4175200 7. require_once('/var/www/astarmathsandphysics/components/com_content/content.php') /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:381 0.1769 4182936 8. ContentController->execute() /var/www/astarmathsandphysics/components/com_content/content.php:42 0.1769 4182936 9. ContentController->display() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:710 0.2532 4806104 10. ContentController->display() /var/www/astarmathsandphysics/components/com_content/controller.php:113 0.2557 4891336 11. Joomla\CMS\Cache\Controller\ViewController->get() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:663 0.2563 4912264 12. ContentViewArticle->display() /var/www/astarmathsandphysics/libraries/src/Cache/Controller/ViewController.php:102 0.2671 5069512 13. Joomla\CMS\Plugin\PluginHelper::importPlugin() /var/www/astarmathsandphysics/components/com_content/views/article/view.html.php:189 0.2671 5069768 14. Joomla\CMS\Plugin\PluginHelper::import() /var/www/astarmathsandphysics/libraries/src/Plugin/PluginHelper.php:182

William Crookes

Sir William Crookes contributed to the discovery of the electron. He investigated the flow of electricity through very low pressure gases using the apparatus shown below.

When electricity flows, regions of the gas emit light. The colour of the emitted light is characteristic of the gas being used.

Besides the light produced by the gas, the glass behind the anode glows too (with a different colour to the gas), suggesting that radiation of some sort is travelling from the cathode to the anode that is able to provide the molecules of the gas with energy. The nature of the radiation was not know and they were called cathode rays because they were emitted from the cathode. Cooke did hypothesise, correctly, that the light given off by the gas and glass respectively was as a result of collisions between the particles that constituted the radiation and molecules in the gas or glass.