A simple homemade greenhouse was constructed as a part of the high school project during the learning-from-home period. The greenhouse was used to show CO₂ absorption by Sansevieria trifasciata during the night, obeying Fick's law of diffusion, while the CO₂ emission by the medium used to grow the plant does not. Although other plants can be used for this purpose, the use of Sansevieria is interesting and offers certain advantages because it absorbs CO₂ during the night. The project could also provide a simple tool for high school students to investigate the absorption and emission of CO₂ from home or in laboratory. Extension of this project to investigate the effect of plant respiration on the environmental parameters, such as decreasing temperature and increasing humidity, is also possible.