Grade 5 · Science · Unit 8 of 12
Forces on Structures
Tension, compression and more
What your child practises
Tension, compression, torsion and shear, loads and natural forces such as wind, snow and earthquakes, and how buildings, animals and safety gear cope with them.
Ontario Curriculum expectation: D1.1, D1.2, D2.1–D2.5 · internal and external forces, loads, and how structures, living things and protective equipment withstand forces
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
A turtle's shell helps protect it from which kind of force?
- Being pressed or crushed
- Being stretched like a rubber band
- Being heated by the Sun
Show answer
Being pressed or crushed
Hint: The domed, hard shell spreads out a squeezing force.
Question 2
Which feature helps a building resist the shaking of an earthquake?
- A heavier roof
- Cross-bracing
- A very thin, tall frame with no supports
Show answer
Cross-bracing
Hint: Diagonal braces stop a frame from twisting or collapsing sideways.
Question 3
The weight of a bridge itself is called its…
- dead load
- torsion
- live load
Show answer
dead load
Hint: A dead load is the permanent weight of the structure.
Question 4
Which internal force pulls a material apart?
- Tension
- Compression
- Shear
Show answer
Tension
Hint: Tension stretches, like a rope in a tug-of-war.
Question 5
A flood-prone community builds its homes on stilts. How does this help?
- It makes the house heavier
- It stops the rain from falling
- Floodwater can pass underneath, so less force pushes on the house
Show answer
Floodwater can pass underneath, so less force pushes on the house
Hint: Moving the structure above the water cuts the damage from the flood.
Question 6
A tall palm tree bends a lot in a hurricane but often does not break. How does that help?
- Its flexible trunk bends with the force instead of snapping
- Its trunk is made of solid steel
- It has no weight
Show answer
Its flexible trunk bends with the force instead of snapping
Hint: Flexible materials can absorb a force by bending.