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: 0.0000 361992 1. {main}() /var/www/astarmathsandphysics/index.php:0 0.0470 1211200 2. Joomla\CMS\Application\SiteApplication->execute() /var/www/astarmathsandphysics/index.php:49 0.0470 1211200 3. Joomla\CMS\Application\SiteApplication->doExecute() /var/www/astarmathsandphysics/libraries/src/Application/CMSApplication.php:267 0.1162 4191864 4. Joomla\CMS\Application\SiteApplication->dispatch() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:233 0.1176 4219280 5. Joomla\CMS\Component\ComponentHelper::renderComponent() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:194 0.1184 4236992 6. Joomla\CMS\Component\ComponentHelper::executeComponent() /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:356 0.1186 4267512 7. require_once('/var/www/astarmathsandphysics/components/com_content/content.php') /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:381 0.1195 4290232 8. ContentController->execute() /var/www/astarmathsandphysics/components/com_content/content.php:42 0.1195 4290232 9. ContentController->display() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:710 0.1636 4959080 10. ContentController->display() /var/www/astarmathsandphysics/components/com_content/controller.php:113 0.1672 5151232 11. Joomla\CMS\Cache\Controller\ViewController->get() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:663 0.1678 5172160 12. ContentViewArticle->display() /var/www/astarmathsandphysics/libraries/src/Cache/Controller/ViewController.php:102 0.1793 5360312 13. Joomla\CMS\Plugin\PluginHelper::importPlugin() /var/www/astarmathsandphysics/components/com_content/views/article/view.html.php:189 0.1793 5360568 14. Joomla\CMS\Plugin\PluginHelper::import() /var/www/astarmathsandphysics/libraries/src/Plugin/PluginHelper.php:182

Photographic Plate

Photographic plates were important in early high-energy physics, as they are exposed by ionizing radiation. X – Rays were discovered by accident in this way and cosmic radiation was investigated through the traces it left on stacks of photographic plates, left on high mountains or carried on balloons.

Subatomic particles may leave tracks on the plate, but this is comparatively unusually, because to do that they must move in the plane of the plate, which is unlikely on the basis of pure chance, so that many particles must be allowed to pass before any tracks are seen in the film

The diagram illustrates tracks on a photographic plate made by alpha particles emitted from an alpha source.

It is also the case that only tracks from more energetic particles are discernible.