Student Activities
Strength VS Weight Lab
Purpose: To demonstrate the effects the reduction of size has on the strength of the objects.
Materials: Wooden dowel rods of different diameters cut to differing lengths so that all objects keep the same diameter to length ratio using a factor of 3. Also needed is string and a bucket and sand to use as mass.
Procedures:
So for example:
- d 1=1mm and l 1 = 50mm
- d 2=3mm and l 2= 150mm
- d 3=9mm and l 3= 450mm
Continue for five total dowel rods and create a data table including diameter, length, volume, and mass held. To determine the volume of a cylinder use the formula Vc= Πr 2h. Take each dowel rod and tie string to the center part of the length and pace rod suspended between two tables. Tie bucket to other end of string. Begin slowly placing sand in the bucket continuing until dowel rod snaps in two. Place bucket on balance and record total mass. Continue for all dowel rods.
Analyze: Looking at data produced generate ideas on how to determine which rod was the strongest. This should develop into a formula for determining the strength to weight ratio for each dowel rod, not which rod held the most mass. Once you determine a procedure write the procedure down and calculate the S/W ratio of each dowel rod creating a new data table to display answers.
Conclusions: When complete check your answers with a neighboring group and see if you have similar results. Which dowel rod did you determine to be the strongest? (the smallest one or the largest one? Describe your conclusion in an explanatory paragraph of what effects strength to weight ratio. Applying your conclusions: determine which is stronger, and ant, human, or elephant and describe why you know this to be true based on our previous observations.
What do you think happens to strength of objects as you minimize its surface area? How does strength to weight ratio compare to surface to volume ratio. Create a new data table determining the surface to volume ratio for each dowel rod and relate it to conclusions from experiment. Describe and comparisons or contrasts that become evident when looking at these two sets of numbers.
Self Assembly Lab
Self Assembly 1
Purpose: To demonstrate the how objects of similar size and/or shape tend to self assemble when placed in a fluid system.
Materials: Plastic Straws, Cheerios, or other uniform cereal, a bowl or container with water in it.
Procedures:
Pt1. Take several straws (at least 10) and cut them to the same length (say 10cm) and place them in a container of water. Observe for two minutes and write observations down. Disturb water by giving gentle shaking to side of container and observe straws for two more minutes. Write observations down. Next take straws and cut them at different lengths and cut tips of several straws to a "V" shape. Repeat original steps and write observations down.
Pt. 2 Take cheerios or other cereal and place them in container of water. Observe for a period of two minutes and write observations down. Using same gentle shaking of container repeats for two minutes and write observations down. (note: you may need fresh cereal for second part as soaking may effect outcome of observations).
Pt.3 Repeat all procedures with a dry container and determine similarities and differences evident between the two types of fluid (air and water).
Analyze: Looking at data from observations generate ideas on what is happening in the fluid, and what is happening to the objects placed in the fluid. Draw conclusions based on observations about why the objects behaved the way they did in the container of water, and in the air.
Conclusions: What do you think self assembly is? Determine your own definition for the process of self assembly based on the observations made in this lab. What practical applications might there be for self assembly in the world of nanoscience?
Self Assembly 2
Purpose: To demonstrate the how objects of dissimilar size, and or shape can be used to self assemble when placed in a fluid system.
Materials: Lego's four each that are 2X8 long and flat, and 8 each that are 2x2 flat. Magnetic mat material used for refrigerator magnets.
Procedures:
Take each piece of Lego and in different areas glue a small piece of magnetic material making sure that the N side of magnet is facing outward for the 2x8 pieces and the S side is facing outward for the 2x2 pieces. Take Lego's and place them in a shallow container like a shoe box. Does anything happen?
Now gently shake the container for 30 seconds (which represents an increase in thermal energy) and observe the inside of the container. Did the pieces self assemble? If yes, what shape did they make? If not try applying more thermal energy or less thermal energy to box (shaking action) until you successfully get some form of self assembly. What shape did you get? Compare your shape to that of a neighboring group. Now determine what shape you want to get and sketch it on lab report. How can you increase your probability of getting this shape each time? Experiment methods to determine how to reproduce your findings. Right down your procedures and share with a neighboring group to see if they can also get the same findings and same shape.
Analyze: Looking at data from observations generate ideas on what is happening in the fluid (the box), and what is happening to the objects placed in the fluid. Draw conclusions based on observations about why the objects behaved the way they did in the container.
Conclusions: What do you think self assembly is? Reflect on your own definition for the process of self assembly based on the observations made in this lab. Would you change your original definition? Is this a process that is easy to replicate? What practical applications might there be for self assembly in the world of nanoscience?
Nano-Project
Purpose: To become better acquainted with nanotechnology and the applications of this field of science.
Procedures:
Students in groups of two to three students will decide what area of nanotechnology they want to study further (medicine, consumer products, building materials).
Students will (either in computer lab or at home) study the broad topic area for a period of two days and determine an area that they want to concentrate on (one medicine, or one product).
Students will report to teacher the desired topic choice. They will then have a period of two weeks to study this topic in depth to learn the following: what is the product or idea, who is working on it and where, why is it being created (purpose), what type of nano-particles are being used, what processes are being used to make these particles, is there any toxicity problems for humans associated with this product, and any other relevant information pertaining to this product or idea.
Students will then create either a PowerPoint presentation based on their research, an infomercial about it, or a sketch using puppets or themselves as actors to teach the rest of the class about there findings. Length of presentation should be more than 10 minutes, but less than 15 minutes, with five minutes of additional time for questions from either students or the teacher. Each group should also create an assessment of their presentation ideas which should be a worksheet, quiz, crossword puzzle or some other individualized work that students can complete for home work.
Grading will be done with a rubric generated for presentations and projects and will be determined on amount of and accuracy of information, and quality of presentation. Project should be worth a minimum of 300 points and a maximum of 500 points. The high point value should generate enough interest in project to get good results.
Create your own rubric using:
http://www.teach-nology.com/ web_tools/rubrics/sciences/
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