The secrets of a sinister glow

Safe­ty pre­cau­tions

Warn­ing! Only un­der adult su­per­vi­sion.

Equip­ment

• phos­pho­res­cent pa­per;
• ul­tra­vi­o­let light;
• flu­o­res­cent ink;
• play mon­ey;
• mark­er;
• scis­sors.

Step-by-step in­struc­tions

Omi­nous Glow Keep­er: Cut some ghosts out of phos­pho­res­cent pa­per, leave them un­der a light for an hour, then turn off the lights. The fig­ures glow!

Se­crets of in­vis­i­ble ink: Write a mes­sage on some play mon­ey and give it to a friend along with a UV light. Your friend can use the UV light to read the mes­sage, then fol­low your in­struc­tions!

Process de­scrip­tion

Omi­nous Glow Keep­er: All sub­stances par­tial­ly ab­sorb light en­er­gy. Some of them use that en­er­gy to glow for a long time af­ter ab­sorb­ing it, slow­ly re-emit­ting the light en­er­gy they have tak­en in. Such sub­stances are said to be phos­pho­res­cent. At some point, the en­er­gy runs out, and they stop glow­ing.

Se­crets of in­vis­i­ble ink: The flu­o­res­cent sub­stances in the ink ab­sorb ul­tra­vi­o­let light and im­me­di­ate­ly emit vis­i­ble light – light with a longer wave­length and less en­er­gy. This is due to the fact that the ink ir­re­triev­ably ab­sorbs some of the light en­er­gy.

Ex­cit­ing and safe ex­per­i­ments await you in the MEL Sci­ence sub­scrip­tion!