Rainbow Cross Craft for Catechism or VBS

Rainbow cross craft completed crosses, catechism craft

This rainbow cross craft is an amazing activity that uses the science of thin films to create rainbows on black paper crosses. How cool it is for the kids to see the nail polish go from clear to many colorful colors! In their wonder, kids will think more deeply about God’s power and all the marveloous science seen throughout his creation! In science, we see the glory of God and his wondrous plan for us!

This activity is fun and so easy to do. It is adapted from the nanotechnology activity on thin films from the National Informal STEM Education Network. Here is their video:

Materials for the Rainbow Cross Craft:

Create workstations on tables in which 4 students will share the same supplies. Allow each participant to make at least 1 rainbow cross.

At each workstation:

Rainbow Cross Craft supplies at catechismangel.com — Supplies needed for making the iridescent rainbow crosses

Black tag board crosses (1 per student) (construction paper is not recommended because it will run in water)
Metallic markers, various colors (optional)
Shallow pans, approx.. 9” x 9” size (1 per 4 students)
Clear nail polish (1 small jar per 4 students)

Drying location:

Establish a drying location by setting out some newspaper away from the workstations.

Show a Completed Cross and Explain the Cool Science:

Hold up a completed cross and point out the cool rainbow colors. Explain the rainbow iridesence by using these pompts:

Finished rainbow cross, catechism craft — Finished rainbow cross

See the cool rainbow? This is iridescent. Where have you seen it before?
- Have you seen rainbows in soap bubbles?
- Have you ever seen an iridescent fish with rainbow colors in its skin?
- Have you ever seen rainbows in a water puddle after it rains? (caused by oil sitting on the puddle’s surface)
Color is created due to interference of light rays as they bounce on the very thin film of nail polish.
- As the light rays bounce off the top and bottom surfaces of a thin film, they interfere with one another.
- The variable thickness of the film is why different colors are seen (thin film interference explained).
Do rainbows that you see make you have a deep wonder for God’s creation? Why?

Demo the Procedure:

Demo how to create a rainbow cross on a sample black cross using steps #1-#6 shown below with the pictures.:

As you demo step #1, give guidelines on what to write on the cross. Think about weaving in something from a recent lesson. For example:
- Jesus lives!
- WWJG
- Praise God
- Holy Trinity
As you do step #4, point out the thin rainbow film created on the top of the water as the nail polish spreads out.
As you do step #5, emphasize that the paper needs to be risen up slowly in a horizontal manner so the thin film ends up on the surface of the paper.

Directions for the Rainbow Cross Craft:

Writing words on cross, catechism craft — Step 1: Write a short message on the cross using the metallic markers.

Submersing cross, catechism craft — Step 2: Fill the pan with a half inch of water. Submerge the cross in water,

Add 1 drop of the clear nail polish to the top of the water, catechism craft — Step 3: Add 1 drop of the clear nail polish to the top of the water.

Film on water above rainbow cross, catechism craft — Step 4: Look for the thin film on the surface of the water. Do you see the rainbows?

Lifting cross up, catechism activity — Step 5: Carefully lift the cross upward so that the rainbow thin film lands on its surface.

Drying the rainbow cross, catechism craft — Step 6: Set the cross on newspaper to dry.

Vacation Bible School Craft Extensions:

This activity works well as a low cost Vacation Bible School (VBS) Activity. So easy to fill a whole 30 min with fun!

Make Rainbow Paper

Provide kids blank rectangles of black paper so the kids make samples of rainbow paper for extra fun. NO need to buy metallic markers! Why not turn them into covers for VBS journals.