Classify the following items as shell, frame, or solid structures, and explain why a cell phone tower is a frame structure and the importance of triangulation.

Here's the completed table and answers to your questions:

Activity 3

Item	Shell structures	Frame structures	Solid structures
Ostrich egg	✅
Milk bottles	✅
Candles			✅
Electricity pylons		✅
Plastic chairs	✅
Wall of a man-made dam			✅
Carved wooden artefacts			✅

Topic 2: Cell phone tower

• Why is a cell phone tower an example of a frame structure? A cell phone tower is a frame structure because it is built from interconnected beams or members that form a rigid framework. Its strength comes from the arrangement of these individual components, which support loads and resist forces without being a solid mass or a hollow shell.

• Why do designers and engineers use triangulation? Designers and engineers use triangulation in frame structures because a triangle is the most stable and rigid geometric shape. Adding diagonal members to form triangles prevents the frame from deforming or collapsing under stress, making the structure strong and resistant to bending and twisting forces.