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Lontar Physics Today
Published by Universitas PGRI Semarang
ISSN : -     EISSN : 28280970     DOI : https://doi.org/10.26877
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This journal aims to be a platform for the dissemination of research findings, conceptual studies, and innovations in Physics and Physics Education that are relevant to academic needs. This journal bridges the worlds of physics research and physics education practices, enabling the results of fundamental and applied studies to be effectively integrated into classroom and laboratory learning. The journal is expected to contribute to the improvement of physics education quality and the development of a generation of physics learners who are critical, creative, and adaptable to future challenges.
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Articles 2 Documents
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Search results for , issue "vol. 5 no. 3: november 2026" : 2 Documents clear
Evaluating the Quality of a Physics Problem-Solving Ability Instrument on Sound Wave Material Using the Rasch Measurement Model Rahma Alliya Aqquilla; Hera Novia; Nurdini
Lontar Physics Today Vol. 5 No. 3: November 2026
Publisher : Universitas PGRI Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26877/lpt.v5i3.926

Abstract

This study aims to analyze the psychometric characteristics of a physics problem-solving ability test instrument on sound wave material using the Rasch model. A descriptive quantitative method was employed, and data were analyzed using Minifacet software. The instrument consisted of eight essay items developed based on Polya’s four stages of problem solving: understanding the problem, devising a plan, carrying out the plan, and looking back. The instrument was administered to 74 Grade XI students from a public senior high school in Cimahi City selected through purposive sampling. Data analysis focused on five aspects: construct validity (unidimensionality), item fit, reliability, item difficulty, and discriminating power. The results showed that the variance explained by Rasch measures reached 57.91%, indicating good unidimensionality. All items met the Rasch model fit criteria and were empirically valid. The instrument achieved an item reliability coefficient of 0.98, categorized as excellent. Item difficulty analysis classified three items as easy (1a, 1c, and 2a), three as moderate (1b, 1d, and 2c), and two as difficult (2b and 2d), demonstrating a balanced distribution of difficulty levels across Polya’s problem-solving stages. In addition, all items exhibited very good discriminating power, with Point Measure Correlation values ranging from 0.57 to 0.80. These findings indicate that the instrument is suitable for objectively measuring students’ physics problem-solving ability on sound wave material. Further development is recommended by expanding the number of items and involving a larger sample to improve generalizability.
Characterization of Optical and Mechanical Properties of Nanocellulose from Oil Palm Empty Fruit Bunch Biomass Using Acid Hydrolysis Wahyu Dian Laksanawati; Ranti An Nisaa; Advent Triyanti Halawa; Novika Aszyiamilatul Utami
Lontar Physics Today Vol. 5 No. 3: November 2026
Publisher : Universitas PGRI Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26877/lpt.v5i3.934

Abstract

This study aims to investigate the optical and mechanical properties of nanocrystalline cellulose (NCC) derived from oil palm empty fruit bunch (OPEFB) as a renewable lignocellulosic biomass for sustainable functional materials. NCC was synthesized through sequential delignification, bleaching, and sulfuric acid hydrolysis at concentrations of 30 wt% and 40 wt%. The resulting NCC was characterized using UV–Vis spectroscopy and tensile testing. UV–Vis analysis showed absorption peaks at 292, 291, and 289 nm for commercial NCC, OPEFB-derived NCC hydrolyzed with 30 wt% H₂SO₄, and OPEFB-derived NCC hydrolyzed with 40 wt% H₂SO₄, respectively. Tauc plot analysis yielded estimated optical band gap energies of 4.25, 4.26, and 4.29 eV, respectively. Tensile testing showed that the commercial NCC exhibited the highest tensile strength and Young’s modulus, whereas the OPEFB-derived NCC showed lower mechanical performance. The NCC hydrolyzed with 30 wt% H₂SO₄ exhibited a tensile strength of 9.65 MPa and a Young’s modulus of 0.330 GPa, while the 40 wt% H₂SO₄ sample exhibited values of 3.99 MPa and 0.176 GPa, respectively. Increasing the sulfuric acid concentration resulted in a slight increase in the estimated optical band gap but a decrease in tensile strength and Young’s modulus. Among the hydrolysis conditions investigated, 30 wt% H₂SO₄ provided a more balanced combination of optical and mechanical properties. These findings indicate that OPEFB can serve as a renewable precursor for the development of cellulose-based functional materials and provide a basis for further investigation of their structural and functional properties.

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