Science Term 2 Exam Flashcards
What is a structure
A structure is something with a definite size, shape, and purpose that can hold a load.
Natural structures 4 examples
Turtle shell / snail shell
Bird’s nest
Ant hill
Spider web
Chicken Egg
Bee hive
A structure built in nature
Built structures 4 examples
Buildings
Vehicles
Furniture
Statues
Fences
Playgrounds
Man made structure
What is the form of a structure
Shape
Size
Materials
What is the form of a structure
Shape
Size
Materials
What is the function of a structure
Its purpose/ability to do something
Form follows function
The form of a structure should be determined by its intended purpose.
You must know what purpose the structure will serve, or what it will do, in order to decide how you will design or build it.
Form should relate to the function of a structure
Shell structure
A shell structure uses a single outside layer to surround an inner object, substances, space etc.
Frame structure
A frame structure uses a framework of connected parts to provide support. Frame structures can be two-dimensional (like a fence or ladder) or three-dimensional (buildings, furniture, etc).
Solid structure
A solid structure is made from one piece of solid material. The mass of the material is used to resist forces.
What is a force
A force is a push or a pull. A force can make an object start moving or stop moving.
Gravity
Gravity is the force that attracts a body toward the centre of Earth. It is a force that is applied to everything on Earth.
Centre of gravity
Centre of gravity is the point from which the weight of a structure may be considered to act (the part with the most weight on average). It is the part of a structure most affected by the force of gravity.
- Why might engineers consider the centre of gravity when designing a structure?
Considering the centre of gravity can help engineers ensure that structures are strong, stable, and able to withstand loads.
What is an external force
An external force acts on an object or structure from outside the structure.
- What is the difference between a contact and non-contact force?
A contact force is applied when two objects touch.
Non-contact forces are created without touching another object.
Magnitude of a force
Magnitude is the size of a force (i.e. a measurement of force)
Point of application
The point of application is the specific location where a force makes contact with a structure.
Plane of application
The plane of application is the side of a structure affected by a force.
Plane of application
The plane of application is the side of a structure affected by a force.
Whats a Load
A load is a weight or source of pressure that creates an external force on a structure.
- What is the difference between a static and dynamic load?
A static load is something that does not change. The size, position and direction of a static load remains the same.
A dynamic load is a force that can change when acting on a structure.
Static load examples
The roof of a house
A book placed on a desk
A bench on the sidewalk
Dynnamic load examples 2
Rain / snow falling on a roof
Wind blowing against a building
People moving within a building
Internal force
An internal force acts from within a structure
Internal form types 4
Compression, tension, torsion, shear
Compression
An internal force that squeezes or presses something together
Tension
An internal force that stretches to expand or lengthen
Shear
An internal force that pushes in opposite directions
Torsion
An internal force applied in a twisting motion
Symmetry
Symmetry is when an object is the same on both sides. In structures, symmetry also refers to a general sense of balance and harmony.
- Describe 3 reasons why symmetry plays an important role in the design of structures
Aesthetics: humans tend to view symmetry as beautiful and appealing
Centre of gravity: In symmetrical structures, the center of gravity is in the middle of the structure so the overall structure can support a greater load
Stability: Symmetry ensures structures are stable because weight is distributed evenly
Design failure
Structures may fail when they are not built according to code or when there are flaws in the architectural design
Improper communication
Improper Communication
If the people who design a structure do not properly communicate with the people who built it, the structure may be built improperly
Poor foundations
Reason
Explanation
Poor Foundations
Soil near the base of a structure may shift due to poor drainage, leaks, or moisture in the land.
Unanticipated forces
Unanticipated Forces
Building designers may underestimate the forces that would be placed on the structure (weather, loads, etc). Some forces cannot be anticipated (natural disasters, accidents)
- Describe each reason why a structure might fail.
Design failure
Improper communication
Poor foundation
Unanticipated forces
- How do sensors help ensure structural safety?
Sensors detect or measure conditions around or within a structure. They can be used to detect unusual stresses placed on a structure.
- Give two examples of sensors that can be used to ensure structural safety.
Seismographs are used to record the motion of the ground during an Earthquake. They can detect if a structure is under stress due to vibrations caused by an earthquake.
Smoke detectors signal when a fire may be present in a building.
- Give an example of how each factor may be considered when designing / building a structure
Economic
How much will it cost to build and maintain?
(Is it affordable?)
What jobs will be created or lost by the creation of this structure?
Environmental
What impact will this structure have on nearby ecosystems?
(habitat loss, emissions, etc.)
Is the surrounding environment suitable for this structure?
(foundation soil, regional climate/weather)
Social
How will this structure be perceived by people in the community?
Will this structure be a tourist attraction?
Will this structure be accessible to people?
(ex: housing, shopping centers - can people afford it?)
(ex: accessibility - is it accessible?)
System
A system is a group of parts that work together to perform a specific task.
Physical system
A physical system is a group of physical parts that work together to perform a specific task.
- Give 3 examples of physical systems.
Human made: Electrical circuits, cars / vehicles, computers, appliances, etc.
Natural: Lakes, rivers, weather, solar systems, ecosystems
Social system
A social system is a group of organisms who join together to accomplish certain tasks
- Give 3 examples of human social systems
Healthcare systems, Education systems, Transportation systems, Businesses, Sports teams / leagues, Social Media
- Give 3 examples of social systems in nature
School of fish, Flock of birds, Colony of ants, Pack of wolves
parts of a system
Input
Things that go into the system, like forces, energy, or raw materials
Process
The actions taken by the system that allow it to convert the input into an output
Output
The things or services that the system produces.
How is feedback used in a system
Feedback uses information related to the outputs to determine necessary variations to the input for the next cycle or loop
Industry
An industry is a combination of systems that work together to produce goods and services
3examples of industries
Transportation industry, agricultural industry, healthcare industry, education industry
- Give an example of a physical and social system that are part of each industry
Industry
Physical Systems
Social Systems
Transportation Industry
Cars, trucks, airplanes, repair equipment
Gas stations, mechanic repair shops, urban planners
Healthcare Industry
X-rays, stethoscopes, needles, heart monitors
Walk-in clinics, hospitals
Education Industry
Computer software, smart boards, laptops
Schools, education centers, daycares
What’s a simple machine
A simple machine is a basic system that makes work easier.
Energy dissipation
Energy dissipation is when energy is lost from a system.
Efficiency
Efficiency is the ability to do something without wasting materials, energy, time, or effort.
- Explain why homework may have been less efficient in the past, and why they are more efficient today.
Process
Past (Less Efficient)
Present (More Efficient)
Doing homework
Finding information: buying books or getting from the library
Accuracy: No calculators, no spell check
Completion: writing by hand
Finding information: use of internet to quickly answer questions
Accuracy: calculators, spell check, etc.
Completion: typing
- List and describe 3 examples of technological innovations that have made systems more efficient.
Wireless internet (communicate / access information easily)
Facial recognition technology (unlock phones quickly and securely)
Smart phones (quick access to internet, multiple functions like calculator, compass, etc.)
- Give 3 examples of things that help make our classroom more efficient.
- Give 3 reasons why public transportation may be more efficient than driving a car.
Resources: More fuel efficient, carries more passengers while using less energy
Labour: One driver per vehicle, passengers can focus on other things
Time: Less traffic, not required to find parking
- Give 2 reasons why public transportation may be less efficient than driving a car.
Routes are not direct, people are required to walk to and from stations
Subject to delays or other issues
Not available everywhere
Automation
Automation is the use of automatic equipment in a system, like manufacturing or production. Automation is the technology that allows manufacturing, production, or other processes to occur with minimal human assistance
How does automation improve efficiency in systems
Automation increases productivity while reducing human labour. It can help remove the possibility of human error from the manufacturing process as well as remove hazards that are found in the factory environment.
Automation Examples 3
Thermostats (automatic temperature control), dishwashers, refrigerators, washers/dryers, automatic door openers, self-driving vehicles, manufacturing machines
- List 3 benefits and drawbacks of automation in systems.
Benefits
Drawbacks
Higher productivity rates
Improves safety
Reduces workweek for factory workers
High upfront costs
Maintenance/repairs
Potential to cause unemployment
Potential harm to social structure
