Lesson Plan 1

Investigating the “Lotus Effect”


Educator: Martin Amoroso

PA Standards:
  •   3.2 C Inquiry and Design
      • Conduct research
      • Use technology to design the investigative  process
      • Analyze and solve the problems related to this investigation
  • 3.6 B Technology Education
      • Use technology to analyze, retrieve and decode knowledge of information gained from the investigation
  • Students will explore the hydrophobic nature of living materials(lotus, cabbage, & broccoli leaves; insect wings, human fingernails)
  • Students will be able to identify relationships between nanoparticles(tiny wax particles found on the surfaces of these materials and hydrophobicity)
  • Students will design an investigative process to observe the “Lotus Effect” (hydrophobicity)
Students will be presented with a picture of a crime scene labeled:

Murder In The Lotus Field

In an enclosed area of the lab/classroom a crime scene is created. A corpse is placed in makeshift garden with fake blood everywhere except on the leaves of particular plants.
  • Students are placed in groups of three and assigned roles of REPORTER,  INVESTIGATOR, COORDINATOR
  • Groups must observe the crime scene for splattered blood and document their observations, noting the places/objects where the blood splatters were seen
  • Diagram of the crime scene will be projected on the board. The group reporters will label the diagram to show the places/objects where blood splatters were observed.
      • INVESTIGATORS will record the collective evidence that are submitted
      • Groups will reconvene, COORDINATORS will collaborate with members, analyze the collective evidence.
      • REPORTERS will announce the group’s  conclusion

Students are then invited to read aloud a case study of actual investigation. The case study will reveal that blood splatters were found in many places except the leaves of particular plants

      • Groups will be then asked to revisit the crime scene with baggies ,collect and samples of leaves with and without blood stains
      • Groups must then formulate a hypothesis to the question: “Could blood have splattered, but not stick to the leaves of particular plants?”

Background Information
Students will be ask to recall observations in the grocery store where water beads up and rolls off the leaves of some plants and fruits
      • The word “hydrophobic” will be explained in terms of its derivatives:

         HYDRO (Water)


      • The waxy nature some leaf surfaces and its “dislike” for water will be explained in terms of bonding and contact forces

Guided Practice
Each group will be asked to answer the question:Could blood have splattered, but not stick to the leaves of particular plants?”
  • Students  will be asked to brainstorm answers to this question(keeping in mind the meaning of the term hydrophobic)
  • Students will be shown Scanning Electron Micrographs (SEMS) of drops of water on Lotus, Elephant ear plant and Mustard Leaves, Lotus. Focus each image to show the inability of water to stick to the surfaces of these leaves (keeping in mind the meaning of the term hydrophobic)
  • Students will be exposed to images, like the ones below, showing the structure and texture of hydrophobic surfaces.


 1"Biological surfaces are usually not smooth. They mostly possess complex three dimensional structures. The size spectrum ranges from macroscopic structures like hairs, via microstructures, far down into the nanoscale range"

2"The leaf surface of the Lotus is not smooth but has bumps is covered by a thin layer of wax crystals (distance 0.2-5µm), which are water-repellent (hydrophobic). These two properties are responsible for the amazing super-hydrophobic, self-cleaning abilities of the Lotus leaves"


Independent Practice 
 Each group will be asked to design an experiment to investigate whether or not: “Blood could splatter, but not stick to the leaves of particular plants?”
  • Students will be required to record the steps of their investigation
  • Students will write a list of materials needed to conduct their investigation
 Material List (additional materials will be supplied based on students’ experimental design)
  • Water droppers
  • Beaker
  • Fake Blood
  • Plant leaves( hydrophilic & hydrophobic)
  • Ziploc bags
  • Water

Enduring Understanding

Making Real World Connections
Students will discuss ways in which humans (from the beginning of time) have used ideas from nature to create tools that can be used to improve our world.
  • Discuss the role of nature in providing us excellent models to learn from: birds inspiring “flying machines”; cocklebur inspiring Velcro, plants inspire many over the counter drugs
  • Discuss the development of very small tools (nanotools) that can investigate materials on a small scale and what may have inspired these inventions
  • Discuss  how  knowledge  about nanomaterials that repel water can be useful to our world
Making Connections To Nanotechnology
The application of nanoscale science as it relates to nanomimicry will be discussed


  • Discuss the application of knowledge gained from plants like the lotus leaf in the designing of technology that mimics the unique structures of these biomaterials
  • Discuss how tools can be designed to study the surfaces of  plants like the lotus leaf
  • Discuss  how  knowledge  about nanomaterials that repel water can be useful to our world


Essential Questions

  • How can information gained from the lotus and other water repellant surfaces in nature improve our world?
  •  Would a window that repels water stay clean?
  • Is it a good idea to have socks that repel sweat?
  • Can we benefit from roads that cannot ice up during winter?
  • What new water repellant products can you imagine?





The surface of a lotus leaf, when observed under a microscope, is covered with tiny wax particles. These particles make the surface of the leaf very rough. The cuticle of the leaf is also made up of a waxy material. The combination of roughness and wax reduce the contact area between the water and the solid leaf surface causing the water to run off. This effect is called the “lotus effect”.

Assessment Strategies
Ongoing Embedded Assessments:
  • Extended tasks involving investigations, experimental designs, analyses, predictions
  • Written, oral and graphic reports of students’ wor

Authentic Assessments:

  • Design challenges for students to create small tools to measure the texture of observable surfaces.
  • Apply the knowledge gained from these measurements and experimental designs to create even smaller tools “nanotools” and make nanoscale measurements of texture of biomaterials and nano-surfaces
  • Exhibit  linkages between knowledge, information and concepts  gained from these investigation and actual situations in the real world

Peer Assessments

  • Panel  discussions
  • Debates
  • Critical reviews of the investigation

Additional Resources