This paper presents experimental and theoretical work, analyzing the performance of single slope solar still. conducted in Cairo, Egypt. A Comparison of the experimental output yield of the solar still with the theoretical output yield was carried out. Getting the results of different parameters as basin water temperature, glass cover temperature, and the productivity of the still. The experimentations without lid were conducted for 7 consecutive days and the daily output yield ranges from (2.8 liter/day to 3.15 liter/day) with an average output yield of 52% when compared with the theoretical output yield. To improve the output yield of the still, a black fibrous lid was used as our testing material and studied its effect on the output yield. Because of its porosity the evaporation surface area of the still was improved, water depth is considered small above its surface. The experimentations with lid were conducted for 6 consecutive days and the daily output yield ranges from (3.1 liter/day to 3.3 liter/day) with an average output yield of 57.95 % when compared to the theoretical yield.