Summer Research Program for Science Teachers


By Annie Chien and Allison Godshall
School of the Future, New York, NY
August 2005
Magic Water©: A Black Box Activity
(PDF Version with Images)
This lesson was originally birthed by School of the Future Science Coach Allison Godshall, and modified by Annie Chien


Teacher’s Notes: Teaching the scientific method involves more than just experimentation. The understanding and use of the scientific method have many components: the reflective, the interactive and the manipulative. A Black Box experiment is a great teaching tool to introduce the scientific method as a generic protocol for problem solving. “Black Box experiments” are problem-based situations the teacher creates that offer a hypothetical mystery (hence, the “Black Box”). The problem is easily researched, observable and is very straightforward. Students then use what they observed to create a hypothesis, design and implement a test to explore their hypothesis, collect data and make a conclusion. While Black Box experiments do not model real life science research and experimentation, it does offer a good opportunity for students to experience the scientific method on their own scale. For older and more advanced learners, it’s also an opportunity reflect and critique its simplicity and to go deeper into the complexity of real scientific problems.

The most popular black box is the sealed shoebox with mystery items inside. Without opening the box, students need to determine its contents by using their senses. This lesson plan offers a unique design and twist to a Black Box mystery. Here is the problem: You are presented with a black box with tubes protruding out of it. If you pour water into one of the inlet tubes, colored water would come out of one of the outlet tubes. Different inlet tubes result in different outlet colored water. You will act as engineers to determine the “plumbing system” of this magic water black box.

Content Objectives: Students will be able to…

Instructional Objectives: In addition to content objectives, students will also be able to…

Materials Check List:

Pre Class Preparations:

Setting up your Magic Water Box is a fun process! The first step is to determine how you want to set up the problem. The design included in this lesson plan is a generic set up, but definitely use our example to build your own “plumbing system” for your students. Use hot glue to connect your tubing.

In Figure B, inlet #1 allows water to drain directly down. This serves as the “control”. 

Inlet #2 was connected to a plastic container and the outlet was higher up on the container in the back - so it took a lot longer for the fluid to leave the box. A sponge soaked in red dye is placed here. As a result, red colored water exits its outlet tube.

Inlet #3 is the challenging one. It has two outlet tubes - one very low on the container (so it would run out early) and another tube higher up that ran into the neighboring container - so fluid would also run out of that tube should enough water be added. In this schema, we put a yellow sponge in container B and a blue sponge in container C. Yellow colored water would exit to outlet 3. When enough water is added to container B, it would overflow to container C where it will run blue. You may want to add some more challenge here for your students. If you pour the water slowly, the yellow water will settle on the bottom of the container and make a layer on top with clear water (thanks to their density properties). This top layer will overflow to container C that will make outlet 4 pour blue-colored water. However, if you pour quickly, outlet 4 will possibility pour out green water. You can even place a green dyed sponge in container C.

The whole milk crate is covered in a trash bag (with the top accessible of course). We added colored funnels on the inlet tubes, but they do NOT correspond to the color coming out. This is just to add a little confusion for the students J You would have to replenish the food dye from class to class.  It made it more interesting to the kids that the color faded.

Remember that how you pour the water, and everything else you do, are observations students will make, hence clues to the plumbing system (timing of the water exiting on the outlet, color of the water, how much you poured, the rate at which you poured). The design of your plumbing system will determine the kinds of clues you offer. Add on challenges by establishing limitations to what the students can/cannot do to experiment with their hypothesis. For example, in this lesson plan, students are only allowed to test their hypothesis by pouring in clear, fresh water. They are not allowed to manipulate the system, for example, using an instrument to poke at the inlet tubes, or pouring in colored water.

The Class Workshop:

Homework Assignment:

Differentiation Tactics

National Standards: Teaching Standard B. Teachers of science guide and facilitate learning. In doing this, teachers: