Inexpensive microscopy for introductory laboratory courses

Abstract

We present an inexpensive apparatus for bright field and fluorescence microscopy with video capture, suitable for introductory laboratory courses. Experiments on Brownian motion and the Boltzmann distribution of suspended particles in a gravitational field are described. The Boltzmann constant is measured in three ways, and the results fall within 15% of the accepted value.

Measuring Boltzmann's constant through holographic video microscopy of a single colloidal sphere

“…From this and the previously discussed values for η, D and T , we obtain k B = (1.387 ± 0.021) × 10 −23 J/K, which agrees to within half a percent with the IUPAC accepted value of (1.3806488 ± 0.0000013) × 10 −23 J/K. This result compares favorably with conventional video microscopy measurements 5,7,8 , which have yielded less precise and less accurate values for k B despite amassing larger data sets. Errors in these earlier studies were dominated by uncertainty in the radius of the diffusing particle, which was addressed by combining results from multiple particles.…”

“…This process has since been automated with the introduction of digital video microscopy 3 and the introduction of automated numerical methods 4 to identify individual spheres in digitized video images and to link their positions in consecutive video frames into time-resolved trajectories for analysis. Quantitative video microscopy of colloidal spheres has been used not only to reproduce Perrin's experiment [3][4][5][6][7][8] , but also to measure colloidal particles' interactions with each other [9][10][11] , to probe the statistical physics of particles moving through structured force fields [12][13][14][15][16] , and as the basis for particle-tracking microrheology 17 , which is used to characterize the viscoelastic properties of complex fluids and biological materials.…”

A Review Paper : Noise Models in Digital Image Processing

“…Fractal noise is caused by natural process. It is different from Gaussian process [8][9][10][11][12]. Figure 2 Visualized vesicles in onion cells (x20) form Brownian motion [10] Although power spectrum of fractal noise, decaying continuously due to increase in frequency.…”

The Flexiscope: a Low Cost, Flexible, Convertible, and Modular Microscope with Automated Scanning and Micromanipulation

“…With flexibility and funding limitations in mind, many researchers have devised excellent cost-saving strategies which include 3D printed microscopes and XYZ translators (Sharkey et al, 2016), (Baden et al, 2015) (Maia Chagas et al, 2017), (Stewart and Giannini, 2016), a $0.58 origami microscope (Cybulski et al, 2014), and modifications to old microscopes (Peidle et al, 2009), (Hernández Vera et al, 2016), (Stewart and Giannini, 2016). These types of systems are advantageous in the field or within incubators but their low cost often equates to a compromise in image quality and a lack of long term stability.…”