It's All in the Shape

Before beginning the activity, explain to students that they will be observing a wide variety of structures (e.g., umbrellas, bike helmets, shoes, trees, flowers, nests) that are both natural and human-made.

As a class, introduce or review the meaning of structure, such as

• “A structure is an object that is able to support a load.”
• “A Load is the weight that a structure supports.”

Note: refer to the Structures Picture Glossary reproducible [Google doc] [Word doc] [PDF] for more definitions that include visual representations. 

Language

Create a word wall of terminology you are likely to use during this lesson such as structure, compression, tension, shape, figure, strength, stability, diagonal, pyramid, cylinder, etc.

To further scaffold the word wall, provide students with visual definitions, like this Structures Picture Glossary. You could print them off to use them in a pocket chart or tape them to a wall. Also, you could print off sets and hand them out to small groups. 

Go through the It’s all in the shape slideshow with students [Google Slides] [pptx] [PDF]. Facilitate a classroom discussion. Ask students to identify the shape(s) before going over the answers and showing them the shape overlays. Encourage students to think about the shapes as part of the structural integrity.

Idea

You could use the slideshow with Pear Deck for an interactive slideshow experience. You could also use Pear Deck as an assessment opportunity. If you are unfamiliar with Pear Deck check out the Pear Deck support page. Note: Pear Deck is free but it does require signing up.

Place students in small groups. Provide each small group with a clipboard, pencil and the Shapes in Structures Observation Sheet reproducible [Google doc] [Word doc] [PDF].

Explain to students that they will be going for a walk to look at structures. As part of this they will also look for the shapes they see in the structures.

The walk could take place inside the school, out in the school yard or in the local neighbourhood.

Note: Alternatively, you could take pictures of structures from around the local community and project on screen for students to look at.

Safety

Review your school’s guidelines and instructions for participating in outdoor activities.

Technology

If your class has access to iPads or tablets, you could use Goosechase which is a fun scavenger activity. For example, you could have students submit a photo of a structure containing specified shape(s) and turn it into a scavenger hunt game.

If you are unfamiliar with Goosechase refer to their FAQ page for support on how to run this activity.

Discussions

Discussion prompts can include:

• “What kind of structures did you see during the walk?”
• “How did you know if something was a structure?”
• “What kinds of shapes did you see in the structures?”
• “Do all structures have the same purpose? Why or why not?”

Idea

Visually impaired students could safely feel structures and describe shapes that they feel. If time is short, students could do this activity individually at home.

Show students this video which shows how you can change the shape of an object. 

Note: You may wish to pause the video at 6:23 minutes as the graph may be too challenging for grade 3s to follow.

Images and Videos

For students who are visually impaired, describe what is being shown on screen.

Place the students in small groups and provide each group with the building materials, fasteners and books to use as weight.

Provide each group with the Making and Testing Shapes reproducible [Google doc] [Word doc] [PDF].

Explain to students that they are to follow the instructions on the four task cards and use the materials provided to make basic shapes and structures (cube, cylinder, cone, triangular pyramid).

It is important to remind students to measure and ensure the sticks are the same length, otherwise, they will build shapes of all different sizes, making it difficult to balance the books and it will not be a fair test based on shape.

You can see a demonstration on how to these shapes are built in this video or this video

They will then use the shapes to test strength and stability using books as weight. There is space on the reproducibles for students to write observations.

If you wish, you can have students, as part of their observation, circle which part of the shape broke first in testing.

Have discussions with students regarding shapes, structures and the forces acting upon them. They may wish to refer to their observations on the reproducible.

Discussions

Discussion prompts can include:

• “What can you tell me about the structures you have created?”
• “What happens if you push (compression) and pull (tension) on different parts of the structure?”

Technology

One student in each group could take a video as tests are done. Students could then watch the videos in slow motion to see the point at which the structures fail.

Students could record and share on Flip as an assessment.

Nature of Science

Review the concept of a fair test with students.

Have students describe how what they did is an example of a fair test. They could identify in each case what changes (the shape) and what stays the same (materials, weights)

Have a discussion with the class to determine which shape they found was the strongest during their exploration by conducting a poll to have students vote on which shape they found to be the strongest. You could do this by a show of hands, using a digital program (e.g., Poll Everywhere, Plickers, etc.).

At the end look at what the most common observation was and ask the class if they agree. Ask students to explain their reasoning.

Note: Depending on how students built their shapes and applied the forces, different shapes may have been the strongest. Refer to Background Information for Teachers section (found below) for more information regarding this.

In general, the cone and triangular pyramid should be stronger than the cone and cylinder because they distribute force from a single point to a wider base. This reduces the strain on the materials that make up the sides.

Have students repeat the process for the shape they found to be the most stable.

Idea

For a no tech option, have the shape names written on the board or chart paper and give students a sticky note, chalk or marker and leave a mark under the shape they want to vote for.

Discussions

Discussion prompts can include:

• “Why do you think that shape is so strong?”
• “Where is compression happening in that shape when a load is applied to the top?”
• “Where is tension happening in that shape when a load is applied to the top?”

Nature of Science

This sharing of results and conclusions is analogous to what scientists do. Sometimes results are shared with small groups, at conferences, etc. Feedback could send them back to the lab to do more research or might help them clarify their thinking. The final step is usually that results are published in a magazine for more scientists to learn from the work they did.