Blooming Paper

Cut out the different types of paper into shapes of flowers.

(What we used: hanji paper, wax paper, origami paper, and A4 paper).

Fold the petals into the center of the flower.

Put the paper flowers in the tray with water.

(The amount of water can vary, as long as it's not too little. In our case, the tray was filled 1/4 of the way.)

Observe as the flowers bloom.

Which paper would bloom first? 

Results:

The hanji paper was the first to unfold and 'bloom' (it happened almost immediately, only after a few seconds on the water), followed by the origami paper and the A4 paper, which started unfolding around the same time. In the 2 minutes and 15 seconds we recorded, the flower made out of the wax paper never quite bloomed.

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How did this happen?

The Blooming Paper experiment takes place due to the capillary action. Because the adhesive forces between the water and the papers are stronger than water's cohesive forces, the liquid is drawn upward through the pores in the papers, causing the petals to unfold and the flowers to bloom.

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Due to the difference in the amount and size of pores in each paper, their rate of capillary action also differs. The fastest paper to unfold, hanji, is the lightest and the most porous paper of the four types of paper we used, and hence its rate of capillary action is the fastest, which causes its petals to unfold first. On the other hand, the only paper that did not bloom, wax paper, tends to be resistant to moisture and is the least porous of the four papers.

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​Useful terms:

• Cohesion

  • ​The attraction between the molecules or atoms of the same substance (e.g. water molecules stick to other water molecules).

• Adhesion

  • The attraction between the molecules or atoms of different substances (e.g. water molecules stick to papers).
• Surface tension
  • The tension of a liquid due to cohesion that allows it to withstand an external force.

• Capillary action​

  • The movement of liquid through the narrow spaces of porous materials due to the forces of cohesion, adhesion, and surface tension.​

Method:

1) Cut out an A4 paper into the shape of a flower.

2) Color the edge of the petals with crayon in one direction (refer to the picture above; however, you don't have to use more than one crayon to color the edges).

3) Put the flower into the tray of water so it floats.

4) Using a pipette, add ethanol to the center of the paper flower and observe what happens.

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(Optional: you can fold the paper just like in the Blooming Paper experiment and watch it unfold before adding the ethanol)

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Results:

The paper flower spins in the direction the crayon is colored. 

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How did this happen?

When the paper touches the water, an adhesion between the paper and the water molecules is created, and the strength of the adhesive force is balanced. When ethanol is added, it is absorbed by the paper flower. The ethanol cannot permeate into the areas colored by the crayons, causing the adhesive force to break its balance.

Therefore, because the colored area has stronger adhesive forces, the paper flower will spin in the direction of the colored edges.

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(Experiment videos below)