Formalin is a toxic chemical that is commonly used as a preservative for biological samples and in various industries. But in practice many abused formaldehyde as a preservative foods such as tofu, meatballs, anchovies, etc. wet fish. When food is consumed can cause interference with the metabolism of the body's organs and systems. A research on the investigation of formaldehyde, especially in out circulating in the market Batusanggkar. Examination carried out by using potassium permanganate (KMnO4) and dragon fruit skin by observing the color changes. Examination of formalin in 5 samples showed similar results to know that the 5 samples contain formaldehyde are all positive.

This research is based on the lack of availibity of student worksheets that use learning models, so that impact on the lack of activeness and understanding of student’s concepts. The purpose of this research is to produce a student worksheet based on POE (Predict-Observe-Explain) on the reaction rate material that is valid and practical. This study uses research and development research metods with development model (define, design, develop, and disseminate). This research was only carried out until development stage. The define stage is carried out to get an overview of the conditions in the field. After getting the conditions in the field, the next step is to design a student worksheet based on POE (Predict-Observe-Explain) on the rate material. After the process of designing the POE based student worksheet has been completed, it this continued white the validity and practicality test that exist at the develop stage. The result of this study indicate that: 1) student worksheet based on POE (Predict-Observe-Explain) have met the valid with 93,14% validation results,2) student worksheets based on POE (Predict-Observe-Explain) has met the very practical   criteria with 91,05% response questionnaire result. The results of this study indicate that the chemical worksheets developed can be used as learning resource for student.

Research has been conducted to analyze the conten of the heavy metal content of lead (Pb) in red pepper (Capsicum Annuum L) circulating in Batusangkar market. Samples of five red peppers were taken from different places in Batusangkar market. The sample was dissolved by using a mixture of sulfuric acid and nitric acid. Furthermore, lead was measured by using atomic absorption spectrophotometry (SSA) at a wavelength of 283.3 nm. The results of the analysis showed that the lowest lead level of 0.2386 mg / kg and the highest lead level of 0.73642 mg / kg. From the five samples, it was found that there was one sample whose lead level exceeded the maximum limit set by National Standardization Council of 2009 about maximum limit of heavy metal contamination in food that is 0,5 mg / kg for lead, whereas for 4 other sample the value of lead level is less from 0.5 mg / kg. In addition, from the five samples, one sample did not meet the safe criteria and the other four samples meet the criteria.

A variety of actions have been made in the face of globalization problems in the 21st century, especially in aspects of education. This is not strangely we are tailored to the most important part of the nation's lives in the future of the progress of the community's intelligence. So in the world of government's interest seeking to apply various curriculum on the educational aspect in Indonesia, the 2013 curriculum. This curiosity of Indonesia wants students to become more independent in mastering the concept of learning and not only accept only, but involved actively seeking problems and finding answers from the problem itself, while teachers are only the guidance to achieve the objective of the learning optimally. To achieve this, then the teacher must use the learning media in the delivery of information that can be used to reveal the learning content. So researchers are interested in using print media as learning media in the form of booklet media that is almost a hurry by rapidly growing digital technology media. Through this booklet media can cause students 'attention and interest in understanding material transmitted with small and less thick book, the content of the main appearing is simply accompanied by the image in supporting students' understanding in learning. In order for the use of this booklet to run the maximum, it takes a learning approach is the sets to add a more fun and interesting learning atmosphere so that the students' obtained science is not forgotten. Where this research uses R & D research to obtain products and test the effectiveness of product development. Through the current MOBIOBER BOOKET-based media initiator researcher has data qualitative and quantitative analysis of product feasibility by validator 79.8% with valid criteria. While the test of the book-based book-based physician from the response questionnaire of 85.1% to 10 students with criteria is very practical, while from the response of the teacher's response obtained a percentage of 86.3% of its criteria is very practical.

This research is motivated by the main problem in this thesis is the unavailability of the Chemistry Practicum Module at SMAN 2 Padang Panjang. The purpose of this research is to find out the validity and practicality of the development of POE-based chemical practicum modules (Predict-Observe-Explain) in order to help learners in implementing of the practicum process implemented at SMAN 2 Padang Panjang to manifest learning in the form of practicum runs smoothly and has clear guidelines. The research method that used by the researcher is a research and development method by developing a 4-D Learning Model (define, design, develop, and disseminate). But in this study only reached the stage of development (develop) due to time constraints. Product eligibility is done by validating the validator. Then, the researcher conducted practicality tests on learners in class X Mipa I SMAN 2 Padang Panjang. Based on the results of product validation, a percentage of 87.97% was obtained with very valid criteria, and the practical percentage of POE-based Chemical Practicum Module (Predict-Observe-Explain) as seen from the results of the student questionnaire of 86.23%.Keywords : Practicum, POE, Electrolyte and Non-Electrolyte