Lab / experiment Grade 6 Science

Ridgeline Water Tower Model: Does Water Height Drive Flow?

A grade 6 lab where students uncover holes at three heights in a bottle, measure how far each stream shoots, and connect water height to pressure and flow.

Grade: Grade 6
Subject: Science
Material: Lab / experiment
Time: 45 min
Prep: Moderate prep
Materials: Empty 2-liter plastic bottle (1 per group), Waterproof tape, Metric ruler or tape measure, Permanent marker, Large tray or a sink, Sturdy block or upturned container about 15 cm tall, Water, Pushpin or small nail (used by an adult only), Paper towels

Standards

6.SP.B.5 Common Core Math

Summarize numerical data sets in relation to their context, reporting the number of observations, describing the attribute measured, giving quantitative measures of center and variability, and relating the choice of measures to the shape of the distribution.

How this material aligns: In Data and Analysis, students record two trials per hole and report an average landing distance, summarizing a small numerical data set as 6.SP.B.5 requires.

All materials for 6.SP.B.5 →

6.RP.A.3 Common Core Math

Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations, including finding a percent of a quantity and converting measurement units.

How this material aligns: Analysis question 4 asks how many times deeper the bottom hole is than the top hole, an 18-to-6 ratio comparison of the kind 6.RP.A.3 targets.

All materials for 6.RP.A.3 →

MS-ETS1-4 NGSS

Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.

How this material aligns: Students run two trials of a bottle model of a water tower to generate landing-distance data at three depths, then use that data in analysis items 6 through 9 to predict how raising the fill line would change every stream, the model-generated data for testing a design this standard names.

All materials for MS-ETS1-4 →

Download Word file

This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will measure how far a stream shoots from holes at three different depths below the water surface.
Students will use their data to explain how the height of water above a point drives its pressure and flow.

Vocabulary

Key words: pressure, water column, flow, distribution

Teacher overview

A water tower holds water up high so homes below get steady pressure. The deeper a point sits below the water surface, the more water presses down on it, and the more pressure it feels. This lab builds a small model of that idea from a plastic bottle. Holes are set at three depths below the fill line, and students measure how far the stream shoots from each one. With the bottle raised so every stream has a long drop, farther streams mean faster water and more pressure, so the bottle shows why a taller water column pushes harder.

Ridgeline Water Tower Model: Does Water Height Drive Flow? — Grade 6 Science

Name: ____________________________ Date: ______________

Procedure

Work in groups of three or four. Each group uses one bottle set up the same way.

Step 1. Mark a fill line near the top of the bottle. An adult then makes three small holes in a straight vertical line down one side, at 6 cm, 12 cm, and 18 cm below the fill line. Call them the top, middle, and bottom holes. Cover all three with one strip of tape.

Step 2. Stand the bottle on a sturdy block or upturned container at least 15 cm tall, at one end of the tray or sink, so the holes face out and every stream falls well below the holes before it lands in the tray.

Step 3. Fill the bottle with water up to the fill line.

Step 4. Peel the tape off the bottom hole only. Measure how far the stream lands from the point on the tray directly below the bottle, in centimeters, and record it. Then cover the hole again.

Step 5. Fill the bottle back up to the fill line. Do the same for the middle hole, then the top hole, filling to the line each time so the water starts at the same height.

Step 6. Repeat Steps 3 through 5 to get a second trial for all three holes.

Step 7. Safety. Only an adult makes the holes with the pin. Water on the floor is slippery, so wipe up spills right away. Do not drink the water used in this lab.

Data & Analysis

Record the landing distance for each hole, in centimeters, for both trials. Then find the average of the two trials.

Hole	Depth below fill line (cm)	Trial 1 distance (cm)	Trial 2 distance (cm)	Average distance (cm)
Top	6
Middle	12
Bottom	18

Which hole's stream landed farthest from the bottle?
Which hole is the deepest below the water surface?
Find the average landing distance for the bottom hole across your two trials.
The bottom hole is 18 cm below the fill line and the top hole is 6 cm below it. How many times deeper is the bottom hole than the top hole?
Compare your average distances. Which hole had the largest average, and which had the smallest?
Describe the pattern between a hole's depth below the surface and how far its stream shoots.
Pressure at a hole comes from the height of water above it. Use your results to explain why the bottom hole shoots the farthest.
A real water tower keeps water high so homes below get pressure. Explain how your bottle shows the same idea.
Predict what would happen to all three streams if you filled the bottle to a higher fill line, and explain your prediction.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key

Answer: The bottom hole.
The bottom hole is deepest below the surface, so it has the most pressure and its stream lands farthest from the bottle. If a group's bottle sat directly on the tray, the middle stream may land farthest because the bottom stream has little height to fall; accept that result with this explanation.
Answer: The bottom hole.
The bottom hole sits 18 cm below the fill line, deeper than the middle (12 cm) and top (6 cm) holes.
Answer: Varies by group.
The answer is the average of the group's two bottom-hole distances. It should be the largest of the three averages.
Answer: 3 times.
18 cm divided by 6 cm = 3, so the bottom hole is 3 times deeper than the top hole.
Answer: Bottom largest, top smallest.
Accept the group's own numbers. In a clean run the bottom hole has the largest average and the top hole the smallest, matching the depths. If the bottle sat directly on the tray, the middle hole may have the largest average because the bottom stream had little height to fall; accept that result with this explanation.
Answer: The deeper the hole is below the surface, the farther its stream shoots. Depth and distance increase together. Accept any answer that states this direct pattern.
Answer: The bottom hole has the most water above it, so the water presses down harder there. More pressure pushes the water out faster, so its stream travels the farthest. Accept answers linking more water above to more pressure.
Answer: The tall column of water in the bottle acts like the tall column in a water tower. Holes lower in the bottle have more water above them, just as homes below a tower have a tall column above them, so both get more pressure. Accept any clear link between water height and pressure.
Answer: All three streams would shoot farther. A higher fill line puts more water above every hole, which raises the pressure at each one, so each stream would travel a longer distance. Accept "farther" with a pressure-based reason.

Differentiation

Support

Pre-mark the three hole depths on the bottle and set it up before class so groups can start measuring right away. Provide a data table with the depth column already filled in, and let students measure to the nearest whole centimeter.

Extension

Have groups add a fourth hole at 24 cm below the fill line, predict where its stream will land compared with the others, then test the prediction and explain any difference from what they expected.

ELL supports

Provide picture labels for "top," "middle," and "bottom" holes and for "distance," and demonstrate one measurement slowly before groups begin. Provide the frame "The ___ hole shoots the farthest because it has the most water above it," and allow numbers-and-arrows notes instead of full sentences.