This is a joint metal shop and science class long-term project exploring the microscopic and macroscopic properties of metals, with the culminating assessment a competition to see which of the students' home-made testing devices is most effective in consistently determining the steel samples' hardness and tensile strength.
From the science aspect, five (112 minute) class periods are devoted to investigating the fundamental physics, chemistry, and material properties of metals, from modifying the crystalline structure to analyzing the tensile strength and hardness.
The metal shop side of it deals with planning and drafting skills, choosing the right materials, designing and building devices to test for hardness and tensile strength of steel, preparing the steel samples, testing them, and analyzing the results.
Realizing that 24 class periods is a significant and possibly prohibitive time commitment, teachers should feel free to pick and choose lessons from the above in order to trim it down to their needs. Build and design times on the machine project can vary greatly and can be determined by the teacher. If limited time is a factor the teacher could simplify the design and build process by providing the students with a pre-drawn machine (end of lesson 2) and just review the elements of the design before the students build it.
The capstone assessment of this project is a competition to see which of the students' home-made testing devices is most effective in consistently determining the steel samples' hardness and tensile strength.
By the end of the project, the students should have the following skills:
Calculating Stress and Strain, Conducting Stress tests, Interpreting and applying Stress-Strain graphs, Interpreting and applying Time-Temperature-Transition graphs, Heat hardening and tempering of tool steel, Plan and draft a design for a student-made machine to test for either hardness or tensile strength, Fabricate the student-made machine, Prepare test samples, analyze test samples.
List of relevant careers: Materials Science, Engineering, Welding
In addition to the CTE/STEM focus of the unit/project lessons, educators will find academic lessons in chemistry and physics that supplement the primary core area of study.
This unit is brought to you by Donald Repucci (CTE), and Mike Tomac (Chemistry and Physics), with support from the CTE Online curriculum leadership team and detailed coordination provided by the Course Team Lead Mina Greas.