Small Building Exercises to learn the Basics of Construction
Gear Ratios
Click here to download a list of Lego Gears and their measurements.
A "Gear Ratio" is written like this: 10:1 and read like this: "Ten to one".
The first number represents the input or drive shaft (crank handle) and the second number represents the output shaft (the black beam with red rod).
10:1 means the input shaft turns 10 times to every one revolution of the output shaft.
Counting the number of teeth on the gears will give you the gear ratio for that configuration. So if the input/drive gear has 6 teeth and the output gear has 24 teeth the resulting gear ratio would be 24:6. Gear ratios should always be reduced, however, so the ratio would be 4:1.
Using the instructions below, build the following configurations and answer the questions.
1. What is the Gear Ratio for the configuration below.
2. Does the output shaft (red rod) spin faster or slower than the input shaft (Crank handle)?
Rebuild into the configuration below, then answer questions 3 and 4.
3. What is the Gear Ratio for the configuration below.
4. Does the output shaft (red rod) spin faster or slower than the input shaft (Crank handle)?
Rebuild as shown below, then answer questions 5 and 6.
5. What is the Gear Ratio for the configuration below.
6. Does the output shaft (red rod) spin faster or slower than the input shaft (Crank handle)?
Rebuild as shown below, then answer questions 7 and 8.
7. What is the Gear Ratio for the configuration below.
8. Does the output shaft (red rod) spin faster or slower than the input shaft (Crank handle)?
Rebuild as shown below, then answer question 9 and 10.
9. What is the Gear Ratio for the configuration below.
10. Does the output shaft (red rod) spin faster or slower than the input shaft (Crank handle)?
Don't take this apart...
Set it aside because the base will be used in the Pushrod/Cam lesson And the Pulley lessonDon't forget to finish the pulley lesson.
Bevel Gears
Bevel Gears allow for a 90 degree turn of the input and output shafts. Built the configurations below and answer the questions
11. What is the Gear Ratio for the configuration below.
12. Does the output shaft (black) spin faster, slower, or the same as the input shaft (gray)?
Rebuild as shown below, then answer question 13 and 14.
13. What is the Gear Ratio for the configuration below.
14. Does the output shaft (black) spin faster, slower, or the same as the input shaft (gray)?
Rebuild as shown below, then answer question 15 and 16.
15. What is the Gear Ratio for the configuration below.
16. !!!Note that the input and output shaft colors have changed!!! Does the output shaft (Gray) spin faster, slower, or the same as the input shaft (black)?
Rebuild as shown below.
17. What is the Gear Ratio for the configuration below.
18. Does the output shaft (Gray) spin faster, slower, or the same as the input shaft (black)?
Check your answers with the Gear Ratio Calculator.
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