**Introduction**

When 30 unit cubes are dropped into a water bottle, the water level will rise. This happens because the cubes displace water as they are submerged, causing the water level to increase. In this explanation, we will explore how the rise in water level can be calculated.

**Understanding Volume and Displacement**

To understand the rise in water level, we need to first understand the concepts of volume and displacement.

- Volume: Volume is the amount of space an object occupies. It is typically measured in cubic units. In this case, the volume of the water bottle is important because it determines how much water can be held.
- Displacement: Displacement is the act of pushing aside a volume of fluid to make room for an object. When an object is submerged in a fluid, it displaces an amount of fluid equal to its own volume.

**Calculating the Rise in Water Level**

To calculate the rise in water level when the cubes are dropped in the water bottle, we can follow these steps:

1. Determine the volume of each cube: Since each cube has equal sides, the volume can be calculated using the formula length x width x height. Let's assume the length of each side is 1 unit, so the volume of each cube is 1 x 1 x 1 = 1 cubic unit.

2. Calculate the total volume of the cubes: As there are 30 cubes, we can multiply the volume of each cube (1 cubic unit) by the total number of cubes (30). So, the total volume of the cubes is 1 x 30 = 30 cubic units.

3. Calculate the rise in water level: The rise in water level is equal to the volume of water displaced by the cubes. Since the total volume of the cubes is 30 cubic units, the water level will rise by 30 units.

**Conclusion**

In conclusion, when 30 unit cubes are dropped into a water bottle, the water level will rise by 30 units. This happens because the cubes displace water equal to their own volume. By calculating the volume of each cube and multiplying it by the total number of cubes, we can determine the rise in water level.