Select a mode below to start experimenting
What: 2 Protons + 2 Neutrons (Helium Nucleus).
Speed: Slow & Heavy.
Stopped by: Paper or Skin.
What: High speed Electron.
Speed: Fast & Light.
Stopped by: Aluminum Foil.
What: Pure Energy Wave (Photon).
Speed: Speed of Light.
Stopped by: Thick Lead.
We start with 200 radioactive atoms. Every "tick", half of the remaining red atoms will decay.