Prototypes allow engineers to test a subset of the design requirements. The test results can inform our understanding of the problem, requirements, and prototype development. Students will test their Neverwet prototypes with different liquids.

Teacher Note: The hand sanitizer should degrade the Neverwet. Students may notice it sticking. They will apply it in Test 2 and then apply water to see if the hand sanitizer has degraded the Neverwet.

View Slides: 1.2.2. BID Ideation

• How do animals stay dry?
• What products could this inspire?

Class Discussion: on what students brainstormed

Play Video: Slow Motion Animals Video (in slides)

Test Lotus Effect

Today we will test the Lotus Effect using the samples prepared from our previous class. Your group will conduct 2 tests and record your results.

View Organizer: 1.2.2 Lotus Effect Test Results & Observations

Procedure:

1. Test 1: Test your samples with the different liquids available in your class (except the hand sanitizer).
2. Record results on the 1.2.2 Lotus Effect Test Results & Observations worksheet.
3. Test 2: Apply the hand sanitizer to one of your samples. Then test with water. Record your results.

You will share your results: [Not every group will have tested every material/ liquid combination]:

Class Discussion:

• Which materials/liquid combinations were the most impressive as far as repelling dirt and water?
• Which materials/ liquid combinations did not work as well?
• What happened when the hand sanitizer was applied?

Teacher Note: The hand sanitizer should degrade the Neverwet. When students apply water after applying hand sanitizer to the Neverwet, the water is absorbed into the fabric.

• Why do you think this happened when the hand sanitizer was applied?
• Which materials would be good for making footwear?
• Which materials might you include when redesigning footwear to keep it looking clean?
• Which material would you choose to go forward with in your design?