Image by: Jim Trodel

Invisible Pictures!

Age Range
3-9 yrs
Setup Time
Under a minute!
Setup Location

When kids grow up in science-friendly homes, they are encouraged to ask questions, think critically, experiment, explain their reasoning, read, write, create models, and watch science programs on TV.

Perhaps the most important discovery is that kids benefit from explicit lessons in critical thinking. Studies suggest that students become better problem solvers--and even raise their IQs--when they are taught principles of logic, hypothesis-testing, and other methods of reasoning.

Studies also suggest that kids learn more when they are required to explain their own reasoning.

This activity piques the child's curiosity in science and also makes for a unique artwork to hang in their room :)


  1. Squeeze and strain lemon juice (quantity can vary based on number of children)

  2. Have your child make a picture on an art paper using lemon juice dipped in cotton balls. They can paint inside the outline of a picture or be creative and make their own

  3. Let the art work air dry - preferably overnight.

  4. Hold the drawing close to (but not on) a light bulb. The design will become visible as the lemon juice turns brown!

  5. Explain the concept of oxidation to your curious little scientist!

Note: Lemon juice is initially not visible to the naked eye because it is composed of sugar, water, and citric acid. None of these components contain much color, and thus they appear “invisible” after the lemon juice dries on paper. The citric acid also inhibits the oxidation of the other components, like lemon, thus preventing the lemon bits from browning. However, the lemon juice can be made visible by the process of heating, which causes the citric acid to decompose and the lemon bits to consequently become oxidized.

Disclaimer: This presents an overview of child development. It is important to keep in mind that the time frames presented are averages and some children may achieve various developmental milestones earlier or later than the average but still be within the normal range of development. This information is presented to help parents understand, at a high level, what to expect from their child. Any questions/concerns you may have about your child’s development should be shared with your doctor.