Heat-Activated Valentine Experiment

Here is a quick tutorial on a fun way to use heat-shrink polymers (Shrinky Dinks) to make a small Valentine's Day craft.

This demo is a good way to get started, but we would love to see how you modify it and make it better!

This demo is not for unsupervised children.

1 sheet of Paper, scissors, 1 sheet of Shrinky Dink, glue, heating method

Optional: 1 Q-tip, lemon juice

Notes on heating method and glue:

These instructions were written for using a heat gun. For glues, super glue or a strong crafting glue seem to work best. However, most glues, including superglue, may not be a good choice if you will be heating the craft in an oven.

If you are using an oven or other heating method, you may need to explore ways of attaching the Shrinky Dink without glue.

Use scissors to cut out two hearts of the same size from the piece of paper. Cut one of the hearts in half from top to bottom. Then cut two small strips of paper from the Shrinky Dink.

If you want to write a secret message later, you may want to cut an extra heart-shaped piece and glue them back-to-back to make the paper you are writing on thicker. This can help the message dry faster and spread less.

Put a drop of Super Glue on one end of the strip of Shrinky Dink and attach it to the whole paper heart, with the Shrinky Dink directed outward to the side of the heart. Repeat the same thing with the other strip of Shrinky Dink on the opposite side of the heart.

Flip the heart with the glued Shrinky Dink strips to the other side so that the heart is on top of the Shrinky Dink strips. Put a drop of Super Glue on the ends of the Shrinky Dink strips sticking out from the heart, then attach one of the halve hearts by placing it on the glue with the straight edge facing outward to the side, and the curved edge facing inward toward the whole heart. Repeat the same step with the other half heart.

Dip the Q-tip into the lemon juice and write a short message on the paper heart in the center. The more lemon juice you use, the darker the message will be after heating it. Wait until the lemon juice dries completely, which can take at least 20 minutes.

For more details on using invisible ink, look here: How to make invisible ink - The National Archives

Using a heat gun, heat up the Shrinky Dink. If you focus the heating on the center, the two halves will fold into the center before your eyes! If you continue heating, it may reopen, but then the message in lemon juice is revealed! See the attached video for an example.

Depending on the temperature of your heat gun, this can take a couple minutes. Heating the lemon juice may take a little longer.

We would love to see how you modify this craft and make it better! Take a look at some of ours in the video below.

We would also love to hear your thoughts:

1. What do you think we could do with heat-activated behavior?
2. What if we could build buildings that deployed when you heated them?
3. Could we make a robot walk using heat?
4. What else is heat-activated that we could use?