Mission 1 - Secret Messages and Art


Chemistry is the study of matter and the changes it undergoes. Matter can be found many states, including solid, liquid, and gas states. (for more specific information on what chemistry is, please visit Chemistry is Everywhere from the American Chemical Society and explore more at Chemistry for Kids with your child.)

Mission 1.1


During this mission you are asked to help heat a secret message with an iron or hot light bulb. Please help your child complete this mission safely.

Lemon juice is a slightly acidic liquid. It will dry mostly invisible when put on a piece of paper. If a drawing or other writing is on the paper, it is less noticeable. For instance, write one letter visibly in pen but leave space between each line. Use the empty space to write another letter in secret ink. A similar technique was used to send secret notes during the revolutionary war (See THIS LINK)!

The message appears because a chemical change takes place when the juice is heated.

Ask your child why the rest of the paper didn't darken.

The reason is that the juice burns at a lower temperature than the rest of the paper.

For more details about the chemistry, please go to one of the websites that inspired this mission at

Science American - Science at Home: Invisible Ink Reveals Cool Chemistry. Go over the description with your child.

Use THIS WEBSITE for additional ideas for other Invisible Inks.

Mission 1.2


During this mission Please help your child complete this mission safely.

CLICK HERE for the entire website description from Science Friday Education for this mission.


You can do a secret message with a crayon resist art method. Please check out the Kids Activities Blog - Crayon Resist activity for another way that can work into a really fun art project.