Main Idea
Students in this learning scenario will explore gears and gears ratios. Τhe purpose is students to build and test robot models in order to recognize that the speed of a gear depends on its position and the number of teeth. Therefore, students will learn how to use gears properly and efficiently.
| Creator | Dimitra Dimitrakopoulou |
| Subject | Computer Science |
| Length | 135 minutes |
| Pedagogical Approach | Haptic learning |
| Competences | Algorithms, Basics |
| Grades | Primary school, 3th grade, students with no special needs |
| Technologies | LEGO WeDo 1 software |
Description
Introduction: Τeacher shows two gears in class and students fill in the first question of the worksheets (Gears are found in cars, bicycles, clocks, elevators and escalators). Afterwards, students are encouraged to freely talk about it.
Where do we use these? What do you think about it? Why we use gears?
A discussion takes place in class on how gears are used. Gears are used to transfer energy in the form of motion from one place to another. Two gears work together to transmit force and movement. Teacher explains that the gear which is closer to the source of power is the drive gear and the gear that receives power from the drive gear is the driven or follower gear. (15 minutes)
Worksheets-Activities: Students built robots in groups of 2-3 children by following instructions. They test them and they make observations. They work at their own pace and they should realize by completing the activities that gears can speed up a process or slow it down. The teacher doesn’t interfere at this point of the learning process. (1 hour)
Discussion: A discussion takes place in class regarding the activities of the worksheets. Students present their answers in each activity. They are motivated to freely talk about what they found difficult, what they didn’t manage to solve and what was interesting. (1 hour)
Worksheets
1. Can you think of any machine in which gears can be found?
2.1. Use the materials depicted in the picture below and built the following model:
2.2. Program your model to move. What do you observe?
A. When one gear is moving the other is moving too.
Yes No
B. The right gear is called the drive gear? (Justify your answer)
Yes No
C. The left gear is called the drive gear? (Justify your answer)
Yes No
The left gear is called the driven gear? (Justify your answer)
Yes No
Do these gears turn in the same direction or the opposite direction?
- 1. Add a small gear and build the following two models:
A B
3.2. Program your models to move. What do you observe?
3.2.1 When the drive is the big gear and the small gear is the driven the speed increases or decreases?
3.2.2 Count the number of gears teeth.
Do you think the speed is influenced by the number of the gear’s teeth?