This study proposes to determine the ability of activated charcoal from sugar palm bunches (Arengga Pinnata MERR) as lead adsorbent (Pb), copper (Cu) and chromium (Cr). The sample was carbonated with a temperature of 200-400°C, then mashed by using mortal and sieved using a size of 100 mesh. Samples were activated with activation temperature variations of 600°C, 700°C, and 800°C and characterized using Scanning Electron Microscope (SEM) with 2500x magnification and Atomic Absorption Spectroscopy (AAS). The SEM results indicate surface morphology of the best-activated charcoal of at a temperature of 700°C with uniformly distributed pore size. In the AAS analysis results obtained for Pb absorption capacity of 0.0082 mg/g and absorption efficiency of 86.86%, the Cu absorption capacity of 0.0203 mg/g and absorption efficiency of 94.37% and Cr adsorption capacity of 0.0243 mg/g and efficiency absorption 96.39%. The value of absorption capacity obtained the result of AAS characterization, and the best adsorption efficiency was at 700°C.

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The research aims to visualize the Fraunhofer Diffraction Equation in the Circle Slit using Excel Spreadsheets and Macro Visual Basic for Application (VBA). The results of this study indicate that Microsoft Excel is able to display a visualization of fraunhofer diffraction shapes on the circle slit. The results of this study can also show a simulation of the formation of fraunhofer diffraction in a slit circle with a gap width (a) and a different wavelength (λ).

In previous research about analysis of slope stability on Lalingato Area, Tirawuta Districts, Kolaka Timur Regency, Sulawesi Tenggara, has been obtained slope instability with factor of safety between 0.38 - 0.64. This instability is caused by activity of geological structure, such as; joint. In the other hand, the effect of slope between 44 - 67 degrees are very influential. The study has conducted a theoretical investigation of the variation of slope form to minimize the landslide of slope. There were two schemes to investigate of slope stability as follows; (a) slope variation, and (b) slope terraces variation. The research has used Ms. Excel and Slide software. Based on the result of research was obtained that slopes with terraces will be easily stable. Meanwhile, if angle of the terraced slopes was given 35° - 44°, so factor of safety was 1.28 - 1.75. The future about the research will be developed to investigate slope stability with inhomogeneous material.

This study aims to determine the understanding of the concept of students on mechanical wave material for students in class XI SMAN 1 Mawasangka Tengah. This type of research is a type of quantitative descriptive research. In this study, the authors wanted to analyze the students' conceptual understanding using the Four-tier diagnostic test instrument. The object of this research is the students of class XI IPA (1) and XI IPA (2) at SMAN 1 Mawasangka Tengah. The data in this study are primary data collected using four-tier diagnostic tests and documentation. The results of the data analysis showed that the average value of the percentage level of understanding of sub-concept students (1) the factors that influence the speed of the wave propagation, namely 4.4% understanding the concept, 81.4% misconception and 14.2% not understanding the concept (2) The current wave period is 23.5% understanding the concept, 64.4% misconception and 13.1% not understanding the concept (3) The frequency of the traveling wave is 32.2% understanding the concept, 51.4% misconception and 16.4 % do not understand the concept (4) Frequency on stationary waves is 36.6% understand the concept, 48.6% misconception and 14.7% do not understand the concept and (5) Wavelength on stationary waves is 15.8% understand the concept, 69 , 9% had misconceptions and 14.2% did not understand the concept. Based on the results of the analysis, it was concluded that: 1) The students' understanding of the concept of mechanical waves was included in the low category. Students who understood the concept were 22.5%, most of the students' understanding of the criteria did not understand the concept of 14.7% and 62.8% indicated that they had misconceptions. 2) Misconception of the high category found in the concept of factors that affect the speed of wave propagation by 81.4%.