Chemistry of Coatings: A Scientific Inquiry Project
Grades: 7-12 Physical Science
Author: Emily Shaub
Source: This lesson is original. This material is based upon work supported by the National Science Foundation under Grant No. EEC- 1542358. Lab section adapted from https://www.teachengineering.org/activities/view/uoh_polymer_lesson01_activity1
The goal of this lesson is to introduce high school science students to scientific inquiry by creating and conducting their own experiment or engineering design under various constraints. The challenge is to create the “best” support beam out of epoxy resin using limited materials and a ratio of their choosing while being the most cost effective. At the conclusion of this lesson, students should have a better understanding of the engineering design matrix as compared to the scientific method and how the two work together to give a scientist meaningful insight. Students will also increase their knowledge of polymers and the importance of polymers in various coatings by conducting research on epoxy resins.
What should students know as a result of this lesson?
- The importance of designing an experiment using the scientific method and engineering design matrix.
- The various types of coatings and the type of bonding that occur in these coatings.
- Coatings are useful and important in many areas of industry and everyday life.
What should the students be able to do as a result of this lesson?
- Formulate various ratios to test the strength of epoxy resins.
- Compare and contrast the steps of the scientific method to the engineering design matrix.
- Conclude that using the scientific method in conjunction with the engineering design matrix is useful.
- Presentation and Worksheets
- Testing Apparatus (see worksheet download for setup)
- Ring stands
- Fishing line/wire
- Styrofoam Cups
Consumable Materials (These materials should be enough for four classes of 30 students)
- Commercial Product: Easy Cast Clear Epoxy
- Wooden stirring sticks
- Glow powder (optional)
- 3 mL syringes without needles
- 10 mL syringes without needles
- Ice cube tray molds
- Assign the Discover and Learn sections for homework (see student worksheets)
Assessment: Discuss the sections that students viewed for homework.
- Go through presentation of scientific method and engineering design matrix briefly if assigned as homework.
- Split the class into two groups and assign half the scientific method and the other half the engineering design matrix.
- Have students use their knowledge of the scientific method and knowledge of epoxies to come up with an experiment to create the best ratio of epoxy to hardener while analysing the cost.
Assessment: Students completion of sections in lab handout.
- Students come up with their “ideal” ratio of epoxy to hardener depending on their research.
- Students then test this using all available materials.
- Students will then test their epoxy resin product by using the beam testing setup and using the three point flexural test (see Beam Testing Set Up Worksheet)
Assessment: Student design set up and the data collected form the beam testing will be formatively assessed. Students will also be evaluated on whether their design passes or fails with the three-point flexural test.
Discussion - As a whole class, each group will share the information they gathered/observed. We will then discuss ways to expand on an experiment and how to redesign/retest. We will also discuss the importance of epoxies and where there are used in everyday life.
Assessment: Final Lab Report (Summative)
Day 3 - Student Lab Write-up
Assessment: Student completion of the lab handout/hyperdoc.
Day 4 - Extension/Differentiation (optional)
- If you have groups that either finish early or honors classes you may assign the extension project where they evaluate their results and redesign their beam in order to better fit the criteria.
- The chemistry of epoxy resins can be further investigated (see appendix in notes)
Assessment: Redesigning and test of their new beam.
- Students should be familiar with the scientific method.
- Students should have a basic knowledge of chemical bonding.
Best Teaching Practices
- 5 E Learning Cycle
- Inquiry Activities
- Conceptual Understanding
- Problem Solving
- Real Life Applications
Alignment with Standards
HS-ETS1-2 Engineering Design
Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, and reliability, and aesthetics as well as possible social, culture and environmental impacts.
HS-ETS1-3 Engineering Design
Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
HS-PS2-6 Motion and Stability: Forces and Interactions
Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.
Science Inquiry and Application - During the years of grades 9 through 12, all students must use the following scientific processes with appropriate laboratory safety techniques to construct their knowledge and understanding in all science content areas:
- Design and conduct scientific investigations
- Recognize and analyze explanations and models
TECHNOLOGICAL AND ENGINEERING DESIGN GRADES 9-12
- Identify a problem or need, consider design criteria and constraints
- Build, test and evaluate a model or prototype that solves a problem or a need
- Apply research, development, experimentation and redesign based on feedback to problem solving
Chemistry-Structure and Properties of Matter
- Intermolecular chemical bonding
- Types and strengths
Students will need to have a basic working knowledge of the scientific method. Students will also need access to the internet to complete the pre lab assignment, research and final lab report.
- Students should wear gloves, safety glass and an apron at all times.
- Require all observers wear safety glasses during beam testing.
Students will know that it is important to design a controlled experiment in order to obtain reliable data. Students will also see that the engineering design matrix is critical in the design and execution of a product that is dependable and cost effective. Students will also know the ideal ratio of epoxy to hardener in various systems and why this is important in coatings.
- Students will communicate their findings in their lab report when explaining how they determined the best ratio of epoxy to hardener and whether their design meets all given constraints.
- Students will be assessed on their overall results of the strength of the beam
- Students should work in groups of 2 in the lab.
This lesson will be a three-day lab with an optional added day for extension.
- Before the Lesson (if using hyperdoc)
- Assign the hyperdoc sections discover, learn and exploration as homework.
- If you are not using the hyperdoc, show the video and make a class discussion at the beginning of class.
- Day 1
- Background Information (PowerPoint/Google Slides)
- Begin scientific inquiry/engineering design
- Students should complete the following sections:
- Pre Lab Questions, Purpose, Hypothesis, Variables, Controls and Procedure
- Day 2
- Lab, Testing Resin
- Preferably do this on a Friday so there is the weekend for the epoxy resin to dry.
- Day 3
- Finish any write-up/testing
- Conclude and tie in with bonding
- Day 4 (optional - if time)
- Students who are finished early or all students may be required to redesign their product based on the findings from the first test results.
- If you do not choose to do this step, require students to analyze and write what they would test and do differently based on their findings after the post-lab questions.
Printable PDF Worksheets
- Teacher Guide - Answer Key
- Student Lab Worksheet/Hyperdoc (Engineering or Scientific Method)
- Engineering Worksheet
- Scientific Method Worksheet
- Supplemental Handout - Beam Testing Set-up
- Presentation - Notes/Slides