Pandemik COVID-19 cukup mempengaruhi sistem pendidikan di Indonesia. Untuk memutus mata rantai penyebaran COVID-19 maka pemerintah dan praktisi pendidikan mencari solusi untuk kegiatan pembelajaran. Bichronous online learning banyak diimplementasikan dalam pembelajaran saat pandemik COVID-19. Namun pembelajaran seperti ini berdampak kepada kesehatan mental pelajar sampai dapat menurunkan motivasi belajar. Dalam penelitian ini peneliti menyebarkan kuesioner untuk mendapatkan informasi tentang motivasi berprestasi mahasiswa dalam bichronous online learning. Kuesioner terdiri dari 72 butir pernyataan dan responden terdiri dari 27 mahasiswa. Hasil penelitian menunjukkan bahwa motivasi berprestasi mahasiswa dalam bichronous online learning terdapat pada kategori cukup. Disimpulkan bahwa pembelajaran daring bichronous tidak menyurutkan motivasi berprestasi mahasiswa, namun tidak pula meningkatkan motivasi berprestasi mereka.

Production of methyl mercury (MeHg) has been shown in laboratory experiments using mercuric chloride (HgCl2) compound released into natural-collected sediments with different geochemical conditions. While the HgCl2 concentration was 30 µl of 113 ppm of HgCl2, the geochemical conditions [pH, salinity, total organic content (TOC), sulfur] of sampled sediments were A: 8.20, 0.00 ppt, 1.97%, and 0.92 ppt, respectively; B: 7.90, 2.00 ppt, 4.69%, and 1.98 ppt, respectively; and C: 8.20, 24.00 ppt, 1.32 %, and 90.90 ppt, respectively. A control was set with no HgCl2. Samples and control were incubated in room temperature of 27 ± 1 °C. Observations were done along 9 days with interval of 3 days. While total Hg was measured using mercury analyzer with Cold Vapor-Atomic Absorbtion Spectrophometer (CV-AAS) system, MeHg was measured by using a gas chromatograph with ECD detector after extracted by dithizone-sodium sulfide extraction method. The result shows that MeHg was found in both treatment and control experiments. The concentrations of the MeHg varied according to the geochemical condition of the sampled sediments. Peak production of MeHg occurred on the third day; however, the production was not significantly affected by the incubation time. Optimum production was found inversely related to the pH, in which highest and lowest the pH formed an ineffectively methylated mercury species. The TOC was significantly correlated to the optimum production. Salinity and sulfate contents were found not correlated to the optimum of MeHg production.   Keywords: Methyl mercury; methylation process; sediment; biogeochemistry

Tujuan dari penelitian ini adalah untuk mengetahui peta tingkat pemahaman konsep mahasiswa kimia semester II menggunakan three-tier diagnostic test terhadap pokok bahasan elektokimia dengan pembelajaran berbasis multimedia. Pelaksanaan penelitian bertempat di Jurusan Kimia, FMIPA, UNIMA pada semester genap tahun ajaran 2018/2019. Metode penelitian yang digunakan adalah One-sho Case, dengan sampel penelitian yaitu kelas ilmu kimia angkatan tahun tertentu sebanyak 12 orang. Instrumen multimedia dibuat dengan memanfaatkan animasi dan video dari internet yang dikemas dalam Ms Power point, dan intrumen tes three-tier diagnostic elektrokimia dibuat sesuai pokok bahasan yang diajarkan. Kemudian instrumen tes divalidasi dan dihasilkan 15 butir soal. Ditemukan data peta tingkat pemahaman konsep elektrokimia yakni jumlah rata-rata mahasiswa yang paham konsep sebesar 41,6%, jumlah rata-rata mahasiswa yang mengalami miskonsepsi baik miskonsepsi (+), miskonsepsi (-) maupun miskonsepsi sebesar 30,033%, jumlah rata-rata mahasiswa kurang paham konsep sebanyak 11,1%, terdapat 8,3% mahasiswa yang kurang yakin dengan konsep yang dimilikinya, dan 8,3% terdapat mahasiswa yang tidak paham konsep elektrokimia. Dengan demikian, disimpulkan bahwa three-tier diagnostic test elektrokimia mampu mengungkap peta tingkat pemahaman mahasiswa tentang topik yang dipilih.

The purpose of this study is to examine the effect of visualization-based inquiry learning methods on student learning outcomes in electrolyte and non-electrolyte solution material. This research was conducted in Kawangkoan 1 Public High School, in the even semester X IPA students, 2018/2019 academic year. Class X IPA students 1 (n = 31) as the experimental class and class X IPA 2 (n = 32) as the control class. The test used in this study statistical t test with significance level α = 0.05 with the testing criteriat> ttable then H0 is rejected and H1 accepted. The results obtained in this test obtained tcount 5.25> ttable 1.670. This test is done not to improve student learning outcomes beyond the minimum standard of completeness criteria in school but this testing is only to see the effect of visualization based inquiry learning methods on student learning outcomes. Based on the results obtained it can be concluded that there are differences in student learning outcomes applied with conventional learning models (control class) and visualization based inquiry learning methods (experimental class)

This study aims to determine the effect of the application of the think pair and share model learning on acid-base material using surrounding materials and tools on student learning outcomes in the experimental class and control class XI Mia SMA N 1 Tombatu. The research sample was students of class XI Mia 1 and XI Mia 2. The results showed that there were differences in student learning outcomes in the experimental class compared to students in the control class who used conventional learning models. Where the average student learning outcomes Experiment class is 81.6 and the average student learning outcomes Control class is 73.9. It can be concluded that the Think Pair and Share (TPS) model of cooperative learning has an influence on the learning outcomes of experimental and control students on acid-base material. Therefore, it can be suggested that the Think Pair and Share (TPS) model of active learning activates students in the learning process in order to improve student learning outcomes.