Name of Activity

Rooftop Rain Harvesting


Eleanor Richard and Eva Philip


Rain, Drought, Roof, Civil, Environmental, Engineering Design Process


Building/EDP, Earth Science

Grade Level

4, 5, 6, 7


2-3 Hours

Brief Description

Students will learn link environmental and civil engineering to design houses that use own rooftop rain harvesting to collect rain water.

This activity is designed to be tested multiple times and let students work there way through the Engineering Design Process many times, in order to allow them to gain understanding and mastery of a complicated challenge.

Learning Goals:

– Understand how humans effect the natural water cycle, what harm that can cause, and generating ways to mitigate it

– Combine multiple ideas into one project

– Understand how to build a sturdy structure

– How to design and perform the best test for a specific design

– How to gather useful data from a test

– How to use data from a test to improve a design

– Understand how a prototype connects to real-world application


Small glass beads to use as water for tests


– tape (duck, masking, scotch) – string

– straws (paper or plastic)

– tooth picks

– Popsicle sticks – glue

– spaghetti

– pipe clears

– cardboard

– paperclips

– paper

– foam core (poster board) – wooden dowels

– plastic utensils – coffee filters

– yarn

– q-tips

– paper cups

– plastic cups

– styrofoam cups – felt fabric

– cotton balls

– scissors


Prepare Video

Knowledge Background

Information on rooftop rain harvest:

Engineering Design Process:



Watch a youtube video about water conservation and lead a conversation about how replenishing ground water supplies.

  • This conversation should allow students to imagine themselves as agents of change, and empower them to make their own prototype of how to best collect water from the roof of a house.

Give students paper to design possible rooftop rain harvesting designs, make sure to list the materials they will have available and ask them to label them on their design in order to get them thinking about materials and feasibility (these often include funnels, gutters, the angle of the roof, rivets in the roof, and many other possible solutions, there is NO right answer!)

Once students have generated their own designs, review the Engineering Design Process. Preference the activity by examining the test and redesign steps, as well as the cyclical nature the process, as students will be completing the process multiple times in this activity.


Have students get into groups of 3 and begin work on their roofs


Circulate the roof and help students if they need assistance in the process of combining multiple ideas into one, and discuss with them that rain does not fall in one place, but all over the whole roof (this was something most of our class did not consider)


Testing procedure: in order to keep the room clean and to see what percentage of the small glass beads (water in this situation) were collected we tested by having student places their houses in a large plastic bin and pouring the bead from right about the house to stop bounce-back.


Once students have reached a testing stage (on average we found after about 12-15 minutes) have groups (or the whole class) generate lists of what they are looking for when hey test with beads. Some examples we saw and encouraged were

  •  how many beads ended up in the collection cup?
  • how many beads ended up in the big container?
  • when did it collect like it was supposed to?
  • where did it work in an unexpected way, was it helpful or not?
  • what aspects of the design were effecting the performance?

When testing we had students ask their group mates these questions, and then asked them our own about how they can use the data from the test to improve their deigns. We did not suggest improvements, but questioned them to explain and expand their thinking.


For the rest of the class, and the next class. We had students continue to redesign and test to improve. Each of students redesign their roof 3-7 times.

We wrapped up the lesson both times with having students reflect on the changes they made, and on how every design improved and changed from the beginning based on data.


Gravity played a huge part in this activity, while it was talked about passingly, it is something that could be a great connecting idea if not driving one.

Online Reference(s)

Previous Activity (if applicable)

Building Strud Structures

Umbrella Unit/Curriculum (if applicable)

Sustainable Houses

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