WONDER #1185: How Does Invisible Ink Work?

Question 1 of 3

The simplest invisible inks made from household substances, such as soapy water, are activated by what?

  1. heat
  2. atomic particles
  3. flour
  4. sound

Question 2 of 3

Today, many amusement parks use invisible inks for hand stamps that are activated by what?

  1. heat
  2. sweat
  3. money
  4. light

Question 3 of 3

Chemically-activated invisible inks can be made from any two chemicals that are what until mixed with each other?

  1. odorless
  2. colorless
  3. orange
  4. inedible

Check your answers online at https://www.wonderopolis.org/wonder/how-does-invisible-ink-work-2.