Solar thermal energy was utilized to heat water for its useful applications. Moreover, solar water heaters have become essential in our lives, and using renewable energy sources is becoming more popular. The current effort is to test and find the effectual solar water heating system. Solar water heater designs have been suggested and produced within two methods whereas forced circulation using a mechanical pump and natural circulation without the use of a pump also recognized as thermosiphon solar water heater. This research was to analyse most efficient Flat Plate Collector (FPC) in terms of heat absorption on Thermosiphon Effect due to energy collection by different colour, material, and glazing. This experiment uses Solar Energy Trainer and MATLAB software to compare the impact of several forms FPC on heat absorption of thermosiphon effect in solar water heater. The most efficient FPC in terms of colour is black collector with higher efficiency of 9.3% compared to white while most efficient FPC in terms of material and glazing are copper and double-glazing collector with 10.86% and 11.15% respectively. The experiment and analysis show that various types of FPC with good heat absorber have higher efficiency.