Portal/Chamber 06

This chamber introduces the concept of pellets, pellet launchers and pellet receivers.

You must be careful around pellets though; as GLaDOS says, they're dangerous, and will instantly kill you if you touch them: "While safety is one of many Aperture Centre goals, the Aperture Science High-Energy Pellets seen to the left of the chamber can and have caused permanent disabilities, such as vapourisation. Please be careful."

- GLaDOS

The objective here is to direct a pellet into the pellet receiver, which will then power the lift, enabling access to the chamberlock. Since there is a fixed orange portal end beneath the pellet launcher, it makes sense to put a portal above the pellet receiver, so that when pellets are launched, they go through the portal, and fly into the receiver. Aim the portal gun at the red lit area above the pellet receiver, and create a portal. The pellet will fly through and be captured by the pellet receiver, which will then power the lift, allowing you to proceed to the next chamber.