The article gives an account of an experiment in which sixty-eight high school students of age 16 - 19 developed spreadsheet applications that simulated fall and projectile motion in the air. The students applied the Euler method to solve the governing differential equations. The aim was to promote STEM to the students and motivate them to study STEM at universities. A questionnaire survey was carried out to find out if the participants found the lessons interesting and if developing and using the spreadsheet models benefited the learning and contributed to the mathematical and technological knowledge of the students.