Background: Critical thinking is an important thing possessed by the students as an order thinking skills which support independent and research-based learning for students. One attempt to fulfill the scientific learning process is conduct a project-based learning by taking into account the motivation and learning styles of students. This study aimed to identify the effect of project based learning, motivation, and visual, auditory and kinesthetic (VAK) learning styles on high school students' critical thinking skills of the ecosystem topic. This research used quasi-experiment with 2x2x3 factorial design. Research was conducted on high school students in grade 10th in Jakarta as many as 348 students were taken by simple random sampling technique. Data was collected by a motivation and VAK learning style questionnaire and critical thinking skills test. Data was analyzed by General Linear Model Uni-variate ANOVA at α = 0.05. The whole group had a normal distributed and homogeneous data. The results showed that (1) there is the significant effect of the Project-based learning on students' critical thinking skills, (2) motivation affects students' critical thinking skills, (3) VAK learning style does not affect students' critical thinking skills, (4) the interaction between the two independent variables was fitted (learning models*motivation , learning models*VAK learning styles , and motivation * VAK learning style)and does not affect student's critical thingking skills, and (5) interaction model of learning , motivation , and learning styles affect the students' critical thinking skills. Based on the results above, students' critical thinking ability can be improved through the project-based learning by taking into several factors such as students' motivation and learning styles.

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The aim of this research is to analyze and examine the inheritance of stomatal density trait and RWL as a variable in drought tolerance ofpeanut. The experiment was conducted by using cv. Kelinci that is sensitive genotype as female parent and US 605 which is tolerantgenotype as male parent, including population off spring from hybrid cv. Kelinci (P1) with US 605 (P2). Stomatal density was determinedby making leaf imprint and by observing leaf imprint under microscope. Relative water loss was determined by dipping peanut leaf in PEG40% for 48 hours. Result of the analysis showed that stomatal density and RWL were not only controlled by qualitative characters of majorgene, but also controlled by quantitative character of minor gene by polygenic with the complex gene action. Both characters seem toinfluence more as genetic factor and have high level fixation additive varians which can give the opportunity to obtain the tolerant offspring.

Research entitled Solubility of Metals Content Bangka Tin Tailings Sand Using Inorganic Acids The sample used was tailings sand from tin mining on Bangka Island which was destroyed using several variations of inorganic acids alone, H2SO4, HNO3 and HCl and mixed with H2SO4-HCl, H2SO4-HNO3, HNO3-HCl and H2SO4-HNO3-HCl. Metal content characterization was analyzed using XRF. From the results of the analysis, it was found that the average heavy metals and rare earth metals were more in HNO3 while for a mixture of acids, namely the use of H2SO4-HNO3.

The magnetite-kaolin was synthesized via coprecipitation method with variation kaolin-magnetite = 1:1, 2:1, 3:1 and the material used to remove Fe metal in groundwater. The kaolin clay, magnetite, and kaolin-magnetite composite was characterized by X-ray diffraction, Fourier transform infra red, and adsorption efficiency test for Fe metal ion. The results indicated magnetite particle adhering to the surface of kaolin by lewis interaction. The results for adsorption kaolin:magnetite = 1:1, 2:1, 3:1 in groundwater showed better results compares to kaolin and magnetite. The optimum kaolin-magnetite adsorb Fe metal in 2:1 ratio with a stirring time of 60 minutes and the eficiency adsorption values is 73.35%. Based on this results, kaolin-magnetite composite can be relied in water treatment with the advantages of high adsorption capacity and the presence of magnetic properties to facilities the procces of transferring adsorbent and adsorbat.