| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Find out at what angle the speed of a bubble is the greatest? Show the results graphically.
Tip: Place the observation values for each angle in the (t, s) -coordinate system.
Answer: 45°