For safety and insurance reasons, you’re required to warn participants about the dangers they may face. After all, it’s learning through science and not dying through science. That said, these nine Aperture Science surplus labels available from ThinkGeek for just $12.99 should satisfy the minimum safety requirements. Affixing said warnings are a non-issue since they’re printed on adhesive vinyl that’s water and UV safe. Stick them to your notebook, cubical wall, or, like I will, bathroom door to make sure people understand the danger ahead.