Hands-on Activity: Materials Properties Make a Difference
Educational Standards :
Pre-Req Knowledge (Return to Contents)
Familiarity with the concept of mass, as well as physical properties of objects as observed by one's senses.
Learning Objectives (Return to Contents)
After this activity, students should be able to:
Materials List (Return to Contents)
Each group needs:
To share with the entire class:
Introduction/Motivation (Return to Contents)
Materials properties are characteristics that we can observe about specific materials using our senses and other tools and equipment. Using our senses alone, what might be some of the materials properties that we can detect? (Listen to student responses.) We can use our senses to observe a material's color, texture, how it tastes and how it smells.
However many additional properties are not measurable with just our senses. Can you think of any? (Listen to student ideas.) These properties include characteristics such as electrical conductivity, density, chemical reactivity, elasticity, pH and boiling point. As scientists and engineers, these are all factors that we may be interested to know in order to better understand and choose the materials we work with.
In addition, a good understanding of materials properties helps scientists and engineers make better decisions about the kinds of materials that are best for specific projects. For example, if you were designing a house in Antarctica, you would want to know which materials have properties such that they hold on to heat and keep it within the house rather than allowing the cold arctic air inside and the warm inside air out. On the other hand, if you were designing a house for a tropical island that gets lots of hurricanes and sometimes flooding, you would want to choose materials that remain sturdy even when very wet.
For this activity, we will pretend to be civil engineers studying materials properties in order to best design a house for the environment it is in and to meet the requirements of the client (what they want) who hired us to design the house.
Vocabulary/Definitions (Return to Contents)
Procedure (Return to Contents)
It helps if the teacher is familiar with the LEGO MINDSTORMS NXT base kit and its software, especially the NXT Data Logging tool. For the activity, it is not necessary to write any programs. Learn more about the LEGO MINDSTORMS Education NXT Software 2.1 at ( http://www.legoeducation.us/eng/product/lego_mindstorms_education_nxt_software_2_1/2240)
It is possible to run this activity without using the LEGO brick and sensors by conducting tests such as the hardness and water resistance tests used in the activity. Consider density, elasticity, tensile strength, as well as thermal conductivity using a simple thermometer. Refer to the resources in the Additional Multimedia Support section for lists of other materials properties.
Before the Activity
With the Students—Testing Procedure
Divide the class into groups of four students each and present all the materials. Have each team build a small enclosed "room" out of just one material and then conduct the following five materials properties tests. Record findings from each test. Then make enclosures and repeat these tests for all materials.
To use the sound and light sensors, it is not necessary to write any programs. Simply use the View command directly from the NXT brick menu during the activity. This menu is what is displayed on the screen as soon as the NXT brick is turned on; Use the right arrow button until the "View" option is available; press the middle button to select it. Once it has been selected, scroll right until the correct sensor is selected. Also specify which port the sensor is connected to.
With the Students—Test Analysis & Application
Attachments (Return to Contents)
Safety Issues (Return to Contents)
Troubleshooting Tips (Return to Contents)
Make sure all sensors are correctly connected to the ports specified in the program.
This sound sensor testing works best in a quiet room.
Make sure the sound sensor is not touching any of the enclosure walls. The NXT sound sensor can be unreliable so it may take a few tries. If you do not get a steady reading, ignore random jumps in the reading and record and compare the approximate range of readings. For example, the readings for cotton balls may vary from 20-40, whereas the readings for cardboard may vary from 50-70.
Assessment (Return to Contents)
Opening Discussion: With various materials on display, discuss materials properties with the class. Ask the students: What are some materials properties? What materials properties can you describe for these materials? Expect answers to pertain to properties that can be observed directly using one's senses, such as color, texture, taste, smell. Use this discussion to learn how broadly students define materials properties at the beginning of the activity.
Activity Embedded Assessment
Results & Conclusions Discussion: After the materials properties tests are completed for all materials, have students share their results and discuss their findings for each of the materials. Ask students the questions in the Procedure section. Use this as an opportunity to gauge students' level of comprehension.
Class Presentations: Have teams present the model houses that they designed and built, describing all the design choices they made, how the materials properties affected their decisions, as well as the materials properties of the used materials. Encourage peer critique and suggestions for improvement. Evaluation of student design choices indicates their mastery of the concepts.
Activity Extensions (Return to Contents)
Assign students to research other materials properties and how they could be tested and measured.
Measure and describe other properties of the same materials using sensors or other equipment.
Activity Scaling (Return to Contents)
Additional Multimedia Support (Return to Contents)
V. Ryan's Properties of Materials page: http://www.technologystudent.com/joints/matprop1.htm Wikipedia's List of Materials Properties page: http://en.wikipedia.org/wiki/List_of_materials_properties
Supporting Program (Return to Contents)Applying Mechatronics to Promote Science (AMPS) GK-12 Program, Polytechnic Institute of New York University
Acknowledgements (Return to Contents)
This activity was developed by the Applying Mechatronics to Promote Science (AMPS) Program funded by National Science Foundation GK-12 grant no. 0741714. However, these contents do not necessarily represent the policies of the NSF and you should not assume endorsement by the federal government.