Questions with the keyword 'change'

• What was the first laser used for and how has it changed from today? by hawkh100m to Mike, Pip, Tianfu, Tim, Tom Comments: (No comments so far )
• How can you change the colours of lasers and is one colour stronger that the other? by izzywizzyxxx to Mike, Pip, Tianfu, Tim, Tom Comments: (No comments so far )