This book contains 25 experiments designed to help students understand some of the science used every day. Each experiment includes a list of materials, a series of easy-to-follow steps, an explanation of the scientific principle demonstrated, and additional scientific facts and information. No special or expensive materials are required. Experiments are organized into five parts: light and optics, heat, earth science, chemistry, and electricity and magnetism. Experiments have imaginative names such as, "I Can See for Miles and Miles,""Steamed Fruit,""Grace under Pressure,""Hi-Ho Silver," and Dimmer Dementia." The book includes a glossary of terms and a reader reply form to suggest experiments created by students or teachers. (MKR)
This book was written on the premise that learning science should be fun and rewarding. The teacher may use it as the foundation for an extended middle school curriculum spanning more than one year or to supplement an existing curriculum with individual sections or exercises from the book. The activities have been organized and designed in a manner that allows the teacher tremendous flexibility. Each activity provides a clear purpose, step-by-step directions, leads easily to conclusions, and includes a teachers guide that has the following parts: goals, student objectives, prelab discussion, guide to the investigation, vocabulary, and additional resources. The guide contains seven sections: "Measuring Physical Quantities"; "Forces, Work and Energy"; "Heat"; "Electricity";"Magnetism"; "Waves of Sound and Light"; and "Hands-On Chemistry." (JRH)
Presents an experiment designed to give students some experience with photochemistry, electrochemistry, and basic theories about semiconductors. Uses a liquid-junction solar cell and illustrates some fundamental physical and chemical principles related to light and electricity interconversion as well as the properties of semiconductors. (JRH)
Chemistry, Demonstrations (Educational), Electricity, Energy, Heat, High Schools, Laboratory Procedures, Light, Science Activities, Science Education, Science Instruction, Secondary School Science, and Teaching Methods
Recommends using dramatic demonstrations on the energy in chemical systems as an audiovisual adjunct to lectures and laboratory sessions. Lists materials needed and provides procedures including safety tips for various experiments to produce chemical light, heat, and electricity; and concludes with hints for preparation/rehearsal. (JM)
Journal of Chemical Education, v66 n6 p510-11 Jun 1989.
Chemistry, College Science, Electricity, Higher Education, Instructional Materials, Light, Overhead Projectors, Physics, Science Activities, Science Equipment, Science Experiments, Science Instruction, Science Projects, Teaching Methods, and Visual Aids
Presents two demonstrations using the overhead projector: (1) describes how to build a projecting voltmeter and presents uses for the classroom; and (2) investigates the color of fluorescent solutions by studying the absorption and transmission of light through the solutions. (MVL)
Lamarche, Camille, Da Silva, Charlotte, Demol, Gauthier, Dague, Etienne, Rols, Marie-Pierre, and Pillet, Flavien
PLoS ONE. 8/13/2018, Vol. 13 Issue 8, p1-15. 15p.
DNA damage, BACTERIAL spores, WATERBORNE infection, DIARRHEA, THYMINE, and DIMERS
Bacterial spores are one of the most resilient life forms on earth and are involved in many human diseases, such as infectious diarrhea, fatal paralytic illnesses and respiratory infections. Here, we investigated the mechanisms involved in the death of Bacillus pumilus spores after exposure to electric arcs in water. Cutting-edge microscopies at the nanoscale did not reveal any structural disorganization of spores exposed to electric arcs. This result suggested the absence of physical destruction by a propagating shock wave or an exposure to an electric field. However, Pulsed-Field Gel Electrophoresis (PFGE) revealed genomic DNA damage induced by UV radiation and Reactive Oxygen Species (ROS). UV induced single-strand DNA breaks and thymine dimers while ROS were mainly involved in base excision. Our findings revealed a correlation between DNA damage and the treatment of spores with electrical discharges. [ABSTRACT FROM AUTHOR]
Ghosh, Pijush K., Debu, Desalegn T., French, David A., and Herzog, Joseph B.
PLoS ONE. 5/9/2017, Vol. 12 Issue 5, p1-11. 11p.
PLASMONS (Physics), RESONANCE frequency analysis, NANOSTRUCTURES, FINITE element method, MAGNETIC dipoles, WAVELENGTHS, and ABSORPTION
Metallic, especially gold, nanostructures exhibit plasmonic behavior in the visible to near-infrared light range. In this study, we investigate optical enhancement and absorption of gold nanobars with different thicknesses for transverse and longitudinal polarizations using finite element method simulations. This study also reports on the discrepancy in the resonance wavelengths and optical enhancement of the sharp-corner and round-corner nanobars of constant length 100 nm and width 60 nm. The result shows that resonance amplitude and wavelength have strong dependences on the thickness of the nanostructure as well as the sharpness of the corners, which is significant since actual fabricated structure often have rounded corners. Primary resonance mode blue-shifts and broadens as the thickess increases due to decoupling of charge dipoles at the surface for both polarizations. The broadening effect is characterized by measuring the full width at half maximum of the spectra. We also present the surface charge distribution showing dipole mode oscillations at resonance frequency and multimode resonance indicating different oscillation directions of the surface charge based on the polarization direction of the field. Results of this work give insight for precisely tuning nanobar structures for sensing and other enhanced optical applications. [ABSTRACT FROM AUTHOR]
Linear PEI is a cationic polymer commonly used for complexing DNA into nanoparticles for cell-transfection and gene-therapy applications. The polymer has closely-spaced amines with weak-base protonation capacity, and a hydrophobic backbone that is kept unaggregated by intra-chain repulsion. As a result, in solution PEI exhibits multiple buffering mechanisms, and polyelectrolyte states that shift between aggregated and free forms. We studied the interplay between the aggregation and protonation behavior of 2.5 kDa linear PEI by pH probing, vapor pressure osmometry, dynamic light scattering, and ninhydrin assay. Our results indicate that: Despite its simple chemical structure, linear PEI displays intricate solution dynamics, which can be harnessed for environment-sensitive biomaterials and for overcoming current challenges with DNA delivery. [ABSTRACT FROM AUTHOR]
PHOTOELECTROCHEMISTRY, COMPOSITE coating, INDIUM tin oxide, COPPER sulfide, ELECTRODES, and GERMANIUM compounds
The ITO (indium tin oxide) conductive glass-matrix CuS-GeO2-TiO2 composite coating was generated via EPD (electrophoretic deposition) and followed by a sintering treatment at 450°C for 40 minutes. Characterizations of the CuS-GeO2-TiO2 composite coating were taken by SEM (scanning electron microscope), XRD (X-ray diffraction), EDX (energy dispersive X-ray), UV-Vis DRS (ultraviolet-visible diffuse reflection spectrum), and FT-IR (Fourier transform infrared spectroscopy). Results showed that CuS and GeO2 had dispersed in this CuS-GeO2-TiO2 composite coating (mass percentages for CuS and GeO2 were 1.23% and 2.79%, respectively). The electrochemical studies (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization) of this CuS-GeO2-TiO2 composite coating electrode were performed in pH = 9.51 Na2CO3-NaHCO3 buffer solution containing 0.50 mol/L CH3OH under the conditions of visible light, ultraviolet light (λ = 365 nm), and dark (without light irradiation as control), respectively. Electrochemical studies indicated that this CuS-GeO2-TiO2 composite coating electrode had better photoelectrocatalytic activity than the pure TiO2 electrode in the electrocatalysis of methanol under visible light. [ABSTRACT FROM AUTHOR]
Vega, Juan F., Vicente-Alique, Ernesto, Núñez-Ramírez, Rafael, Wang, Yang, and Martínez-Salazar, Javier
PLoS ONE. 2/17/2016, Vol. 11 Issue 2, p1-17. 17p.
ELECTROSTATICS, ELECTRIC charge, PAPILLOMAVIRUSES, VIRUS-like particles, TRANSMISSION electron microscopy, and ELECTROPHORESIS
The stabilization of human papillomavirus type 16 virus-like particles has been examined by means of different techniques including dynamic and static light scattering, transmission electron microscopy and electrophoretic mobility. All these techniques provide different and often complementary perspectives about the aggregation process and generation of stabilized virus-like particles after a period of time of 48 hours at a temperature of 298 K. Interestingly, static light scattering results point towards a clear colloidal instability in the initial systems, as suggested by a negative value of the second virial coefficient. This is likely related to small repulsive electrostatic interactions among the particles, and in agreement with relatively small absolute values of the electrophoretic mobility and, hence, of the net surface charges. At this initial stage the small repulsive interactions are not able to compensate binding interactions, which tend to aggregate the particles. As time proceeds, an increase of the size of the particles is accompanied by strong increases, in absolute values, of the electrophoretic mobility and net surface charge, suggesting enhanced repulsive electrostatic interactions and, consequently, a stabilized colloidal system. These results show that electrophoretic mobility is a useful methodology that can be applied to screen the stabilization factors for virus-like particles during vaccine development. [ABSTRACT FROM AUTHOR]