Leaf hydrophobicity

Safety

• Carefully review the general safety advice on the back of the box cover before starting the experiment.
• Warning: Some plants contain allergens which can cause an allergic reaction. Irritant sap of some plants may cause a burning sensation and sometimes blistering of the skin.

Disposal

• Dispose of solid waste together with household garbage.

Scientific description

Have you ever heard of the lotus effect? This is an effect resulting from extremely low surface wettability (or high hydrophobicity), named after the plants from the genus Lotus. Upon contact with the leaves and petals of these plants, water forms spherical droplets and easily skitters off of them. Though this effect is named after them, Lotus plants are not the only ones with this property.

With the Lotus effect specifically, the leaves stay dry due to the special structure of their surface, which does not allow water molecules in. However, this is not the only hydrophobicity mechanism a leaf can have—often, leaves are coated with a special substance composed of molecules that repel water molecules.

Why might plant leaves and petals be hydrophobic? For extra cleaning! As they roll off of leaves, the water droplets take dust particles with them.