Staff Sign-off Sheet
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Staff Sign-off Sheet
Pre-lab Discussion Questions
Before you make observations with the microscope, you will run simulations of Brownian motion in Matlab. Show your simulation results and the answers to the following questions to a GSI before you start.
1. What are the masses of the various nanoparticles you will be observing in the lab? Data sheets for the nanoparticles are available in the 'BIO' experiment folder on the 'Advanced Lab' share.
2. Copy the 'BIO Lab Work' folder from the share to your own 'My Documents' folder. Run the 'Brownian Motion in Matlab' exercise.
3. Using the microscope, you will observe a minimum of two different size particles in at least four different viscosity solvents. Choose the conditions you plan to observe and simulate them in Matlab. (You should choose at least one particle 1 µm or larger and one smaller.)
4. Use your simulated data to calculate the diffusion coefficient, D in each case. Explain how you arrived at your answer.
5. What is the uncertainty of your estimate of D? How does it vary with the number of simulated data points? Explain your strategy for making observations in the lab. What additional sources of error will come in to play? How will you account for them?
Staff Signature Date
Mid-lab Questions
1. Using a slide with a combination of polystyrene beads and gold nanoparticles, show how to set up Köhler illumination.
2. How many nanometers per pixel are captured at 10x, 20x, and 40x?
3. Draw diagram of darkfield illumination. Explain how it is possible to see 40 nm objects with visible light (400-750 nm wavelengths).
4. Set up dark-field illumination.
Staff Signature Date
Completed on the second day of lab? (circle) Yes / No
Mid-lab Questions 2
1. By day three of this lab, you should have made several movies and particle tracks. Show one of the particle tracks to an instructor. What value of D did you calculate from the track?
Staff Signature Date
Completed on the third day of lab? (circle) Yes / No
