Sunscreen is an active ingredient capable of absorbing, reflecting, or dissipating UV radiation at a wavelength of 290-400 nm. Sunscreen cream can absorb at least 85 % of sunlight at a wavelength of 290-320 nm [1]. Exposure to excessive sunlight can cause skin wrinkles, black spots, premature aging to cause skin cancer. Ultraviolet rays can be divided into UV-A with wavelengths of 320-400 nm and UV-B rays with wavelengths 280-320 nm and UV-C rays of 100-280 nm length [2]. UV-A rays have less energy than UV-B and UV-C, but have a greater light identity up to the surface of the earth, causing skin discolouration to reddish brown. UV-B rays have greater energy than UV-A but fewer light intensities reach the surface of the earth so that less effect on the body. While UV-C rays are the highest and most dangerous UV rays among other UV rays but will naturally be absorbed by the ozone layer in atmospheres [3]. One way that is done to overcome this is with the use of sunscreen cream. Sunscreen is a compound that can be used to protect the skin from sunburn, especially ultra violet (UV). To protect the skin from UV radiation, it is made cosmetic sunscreen that can absorb ultraviolet rays from sunlight effectively. Sunscreen material can be obtained synthetically or naturally. Synthetic sunscreen materials are often used in sunscreen preparations as physical and chemical absorber. For UV blockers physically commonly used TiO 2 and ZnO to block UVB/UVA [4]. The

This study aimed to determine the anthocyanin content present in Flacourtia inermis peel and its ultraviolet-visible absorption potential as a dye agent. This work focused on developing dye-sensitized materials that require natural eco-friendly dyes which are easily reproducible. The red to purple colour of Flacourtia inermis peel indicates the presence of anthocyanin contents, which were derived from flavonoids. Hence, anthocyanin analysis, UV-vis absorption test and electronic transition study were conducted for information regarding the potential use Flacourtia inermis fruit peel in natural dyes. To determine anthocyanin and absorption ability, UV-visible spectrophotometry was used. Furthermore, the electronic transition of anthocyanin was determined using the semi-empirical method of ZINDO/s. The results indicate that total anthocyanin content of Flacourtia inermis peel was 10.35 mg/100 g, with UV absorption occurring at erythema transmission percent of 0.7553; the pigmentation transmission percent was 0.78696, whereas the electronic transitions of molecular orbitals were observed at an optimum wavelength 425.5 nm visible area, with intensity 1.1233. Molecular orbital levels were six, with two electronic transition shifts, namely n→π* and π→π*.

Artikel ini merupakan bagian dari penelitian pengembangan media video tutorial model-model pembelajaran inovatif untuk meningkatkan kompetensi pedagogik mahasiswa calon guru. Artikel ini bertujuan untuk mendeskripsikan hasil uji kelayakan media video tutorial model pembelajaran berbasis masalah pada materi kalor dalam kegiatan pembelajaran di kelas. Metode penelitian yang digunakan ialah penelitian dan pengembangan (Research and Development). Data dikumpulkan melalui teknik non tes dengan instrumen lembar validasi yang dikemas dalam bentuk angket tertutup yang ditujukan untuk ahli materi fisika, ahli media pembelajaran, ahli pedagogik dan guru-guru fisika. Teknik ananlisis data dilakukan melalui teknik analisis deskriptif kuantitatif. Hasil uji kelayakan media menurut ahli materi fisika dikategorikan sangat baik (81,9%), menurut ahli media pembelajaran dikategorikan sangat baik (85,2%), menurut ahli pedagogik dikategorikan sangat baik (90,02%), menurut guru fisika untuk aspek desain media dan keterlaksanaan sintaks model pembelajaran berbasis masalah dikaterorikan baik dengan besar persentase masing-masing sebesar 74,6% dan 73,8%. Berdasarkan hasil uji validasi disimpulkan media video tutorial model pembelajaran berbasis masalah yang dikembangkan telah layak untuk digunakan sebagai media pembelajaran. Kata Kunci: Media, Video Tutorial, Model Pembelajaran Berbasis Masalah

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This study aims to determine the effect of the variation problem based learning model with the implementation of Ice Breaker towards student’s learning outcomes of class 11 IPA at SMA Negeri 3 Taliabu Utara about chemical equilibrium. The type of research used in this study is experimental research with a one group pretest posttest design. The samples of this study were 20 students of class 11 IPA at SMA Negeri 3 North Taliabu which were selected by using saturated sampling technique. The instruments used in this Study were in the form of essay questions consisting of 8 items to measure students’ learning outcomes and observation sheet to measure of the effective and psychomotor domains. The data analysis technique used in this study was inferential statistical analysis using SPSS 21.0. The results of analysis showed that there effect of variation problem based learning model with the implementation of Ice Breaker towards students’ learning outcomes of class 11 IPA at SMA Negeri 3 North Taliabu about chemical equilibrium, with the results of hypothesis test obtained:tcount<ttable or -8.205<1.729, meanwhile the results of affective domain anlysis reached 53 and psychomotor domain reached 53.