Hands-on Activity: Molecules: The Movement of Atoms
Educational Standards :
Pre-Req Knowledge (Return to Contents)
Students should be familiar with basic chemistry, including atoms, and with ChemDraw and LEGO NXT applications. Refer to the guides listed in the Materials List for how to use these programs.
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:
Note that single licenses and site licenses are available; site licenses may make sense for schools with high use.
Introduction/Motivation (Return to Contents)
In some Hollywood movies, such as Avatar or Ironman, the scientific and engineering heroes found ways to modify molecules to save the world. For example, in Avatar, researchers genetically engineered Na'vi bodies that could survive on Pandora. In Ironman, Tony Stark used molecules to repair his chest injury so he could fight crime.
Molecules have been used to fight some of the many human challenges in the world. For example, curcumin is a small molecule that is an anti-tumor, anti-amyloid and anti-inflammatory. Researchers are using this powerful molecule to find cures for cancer. Vitamin A is another small molecule that is used in anti-aging creams. Some molecules can convert sunlight into energy, and are used in organic solar cells. Kevlar (poly paraphenylene terephthalamide) molecules are spun into incredibly high strength fibers that are used in body armor and advanced sports equipment. In all of these cases, the structure of the molecule helps give it its desirable properties.
When engineers want to create a molecule to solve a problem, they need to think about what kind of structure is required to achieve the desired function. However, formulating an image of how molecules move is hard to do in your head! This is especially true for more complicated molecules. In studying existing molecules or designing new ones, engineers use molecular models to help them visualize molecular structure. To help us understand how engineers use molecular design to solve complex problems, we will develop a model to simulate the movement of molecules in 3D space with the aid of robotics and technology.
When you hear the word molecule, what comes to mind? Can you formulate an image of the moving molecules in your head? I bet it is difficult to imagine how molecules will behave when they are surrounded by other different molecules. To help us with that, we have simulated the movement of molecules in 3D space with the aid of robotics and technology.
In this activity, you will expand your knowledge of the movement of molecules in 3D space. You will learn new vocabulary words such as Newman projections and staggered/eclipsed conformations. You will learn about the size of atoms and how the size affects the steric strain of the molecule. You will also learn some new technology — how to program the movement of molecules with the aid of LEGO robots.
Vocabulary/Definitions (Return to Contents)
Procedure (Return to Contents)
Student groups design molecular models and try to control how fast the molecules move with the light and ultrasonic sensors (see Figure 1). Specifically, they monitor the movement of the molecules through the display screen on the NXT brick, which shows the output of the sensor on the NXT screen. Students work in groups during the entire activity.
To begin, they brainstorm several design ideas and make sketches of their molecular modeling robot designs. Then they build their molecular modeling robots in groups and submit them to class critique, modifying their designs to incorporate feedback and suggestions for improvement, and make sure that their designs work (should be similar to Figure 1). Expect students be able to show the teacher that they can control the speed of the molecules with the aid of the sensors.
The staggered and eclipsed conformation positions can be shown through the programming of the robot. The robot can turn the atoms around, resulting in a molecular model simulations that are visual and tangible to students.
Before the Activity
With the Students—Design and Build the Robot
With the Students—Program the Robot
Attachments (Return to Contents)
Investigating Questions (Return to Contents)
How do atoms behave in a molecule? (Answer: Atoms may either share or transfer electrons in a molecule, depending on the type of bond that forms.)
What is the difference in energy requirement between staggered and eclipsed? (Answer: The eclipsed conformation requires more energy to maintain because it is energetically unfavorable.)
Which conformation experiences more steric hindrance? (Answer: The eclipsed conformation experiences more steric hindrance because more atoms are fighting for space.)
Assessment (Return to Contents)
Guessing Game: Ask students to predict: Which conformation requires the most energy? (Answer: Eclipsed conformation because of steric hinderance.)
Activity Embedded Assessment
Design a Robot: Ask students what they learned from the robot design and what they learned from the ChemDraw program. (Answer: ChemDraw shows students the molecules with the appropriate sizes and energies, but the molecular modeling robot provides insight on how the robot moves with the different sizes atoms.)
Worksheet: Have students complete the Molecular Modeling Worksheet late in the activity or at activity end. Review their drawings and answers to gauge their comprehension of the material.
Activity Extensions (Return to Contents)
If time permits, challenge students to design their own molecular robot programs to do the same thing but in a different way. For example, vary the size and color of the molecular model atoms so the sensors respond differently and create programs that work with them, generating different data logging results. The robot should be able to recognize different ball sizes with the ultrasonic sensor and different colored atoms with the light sensor. Provide students with different sizes of Styrofoam balls and colors of construction paper to do this.
Challenge students to design a new molecule to deliver a drug in the body. Students should think about where the drug will bind to the molecule (or perhaps whether the molecule will "cage" the drug), and how the molecule will travel through the body (including how hindered the molecule will be due to its structure). Is the goal of this drug to be easy or difficult to break down and release the drug? If time allows, students can model these novel molecular designs with ChemDraw and/or their robots (this new molecule may require robot modification).
Activity Scaling (Return to Contents)
ContributorsJennifer S. Haghpanah, Jill Fonda, Noam Pillischer, Jin Kim Montclare
Copyright© 2013 by Regents of the University of Colorado; original © 2011 Polytechnic Institute of New York University
Supporting Program (Return to Contents)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.