How to Dye a Plant With Science?

The Color Changing Chinese Cabbage is a colorful STEM science project with materials easily being found in the kitchen. Usually, the rose is used in this experiment but we have tried rose many times and the effect is not that clear. We tried the Chinese cabbage and it works perfectly. It is a lot easier to dye the Chinese cabbage than the rose.

Ages: 3+                  Est. Time: <24 hours

 Safety 

Be careful with the fragile glassware.

 Materials List 

• Fresh Chinese cabbage
• Food coloring
• Water
• 100ml beaker
• Glass rod

 Instruction 

Step 1/3 – Drop a few drops of different food colorings into each five cups of water. Stir with a glass rod. (the more food coloring, the better the result.)

Step 2/3 – Place five pieces of Chinese cabbage separately into five each beaker.

Step 3/3 – Waite some time and you get your color-changing plant. (Usually, it will change its color for about 2 hours. If you want to make the color deeper, you just need to leave it longer or add more food coloring.)

 Troubleshooting 

Why mine did not work?

– Make sure the Chinese cabbage is fresh and you also can add more food coloring.

 Scientific Description 

Capillary action is the ability of a liquid to flow in a narrow room without the assistance of external forces, sometimes even defying gravity. The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube, in porous materials such as paper and plaster, in some non-porous materials such as sand and liquefied carbon fiber, or even in a biological cell. It occurs because of intermolecular forces between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and adhesive forces between the liquid and container wall act to propel the liquid. In this experiment, there are lots of small rooms in the Chinese cabbage, which will suck the dyed water up by Capillary Action. There are still many cases behind Capillary Action in our daily life, such as the liquid absorption by a towel, alcohol absorption by a wick and etc.

 Extensions 

Try different vegetables, such as celery, bean sprouts, etc.

 Disposal 

Pour the liquid into the sink. The cabbage is treated as domestic garbage. And, do not forget to wash what you have used.