Big Hero 6 Science Experiments : Fred’s Super Hero Invisible Ink

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By In The Playroom

Today I’m sharing another cool science experiment inspired by Disney’s Big Hero 6. This activity is inspired by the crazy and awesome character Fred, and his love of all things super hero and spy.

Your kids can enjoy playing super heroes with these fun and simple secret messages using lemon juice “invisible ink.”

Big Hero 6 Science Experiments Freds Invisible Ink

To make Fred’s Super Hero invisible ink you will need

  • Half a lemon
  • Bowl
  • White paper
  • Cotton swab (Q tip)
  • Lamp, light bulb or flame (with adult supervision)

How to make the invisible ink


Squeeze the juice of 1/2 a lemon into a bowl and mix in a few drops of water

Dip your cotton swab into the mixture, and using your cotton bud or q tip as a pen, and the mixture as your ink, write your super hero message onto your white paper.

Allow the lemon juice ink to dry so that it becomes completely invisible.

When you’re ready to read your secret message, heat the paper by holding it close to a lamp or light bulb and watch the message appear!

How does this work? The science behind lemon juice invisible ink

The acid in the lemon juice weakens the section of paper where the message has been written. When heated, the sections of paper with the acid on them will turn brown before the rest of the paper – allowing your secret message to be uncovered.

If you would like to download and print these instructions: Click here for the pdf file

write secret messages in lemon juice, classic science experiment for kids

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Printable image  ©Disney 2014

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Anna Marikar, mum of four and seasoned blogger, has spent over a decade sharing her parenting journey and passion for kid-friendly crafts and free printables.
Her easy-to-follow craft ideas and practical parenting advice have transformed In The Playroom into a cherished resource for parents.

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