The hypothesis of the study were: (1) There will be no significant difference between the pretest and posttest mean scores of the experimental group pertaining to the concept of day and night. (2) There will be no significant difference between the pretest and posttest mean score of the control group pertaining to the concept of day and night. (3) There will be no significant difference between the posttest mean score of the experimental and control groups pertaining to the concept of day and night. (4) There will be no significant difference between the mean scores of the experimental and control groups pertaining to the concept of day and night. (5) There will be no significant difference between the posttest mean scores of boys and girls of experimental group pertaining to the concept of day and night. (6) There will be no significant difference between the posttest mean scores of boys and girls of control group pertaining to the concept of day and night. (7) There will be no significant difference between the mean scores of boys and girls of the experimental group pertaining to the concept of day and night. (8) There will be no significant difference between the mean scores of boys and girls of the control group pertaining to the concept of day and night.

Researcher developed three lessons and each lesson’s time was 35 minutes. The sample comprised of 200 Students of Grade III from 5 different Schools of Lucknow City. The sample was selected with the help of Random Sampling Technique.

The researcher developed Concept of Day & Night test (Split-half= 0.66) and used for data collection.

The study was Experimental in nature. Randomized Pretest – Posttest Control Group Design was used.

The data were analyzed with the help of t – Test.

The findings of the study were: (1) The children belonging to the experimental group were able to better comprehend the phenomenon of day and night. (2) Expository teaching approach could be successful for grade three children. (3) Sex difference was not found as a significant variable in the understanding about the reasons behind the occurrence of day and night. (4) Especially designed lesson pertaining to the understanding of the reason behind the occurrence of day and night have been found effective for grade three children.