Gr 7 Unit D Test (Section 3-4)

Question 1

What is deformation?

Answer 1

The change in size or shape of an object

Question 2

What is flexibility?

Answer 2

The ability of a material to be bent under force but not break. It helps prevent a structure from deforming and breaking

Question 3

What are qualitative observations?

Answer 3

Qualitative observations deal with data that can be observed but not measured. (no numbers)

Question 4

What are quantitative observations?

Answer 4

Quantitative observations deal with quantities and numbers

Question 5

What are the properties of a material?

Answer 5

Brittleness, ductility, hardness, plasticity, resistance to heat/water, compression, and tensile strength

Question 6

What is ductility?

Answer 6

Ductility describes the property of a solid material and how thin it can be stretched when in tension. If a material is ductile, it could be stretched into a wire

Question 7

What is hardness?

Answer 7

How hard something is

Question 8

What is plasticity?

Answer 8

The property of how easily something can be easily shaped or molded

Question 9

What is resistance to heat/water?

Answer 9

How much an object can resist heat flow and penetration by water

Question 10

What is compression (as a property)?

Answer 10

How well an object can deal with compression

Question 11

What is tensile strength?

Answer 11

Tensile strength is a measurement of the force required to pull something to the point where it breaks

Question 12

What is brittleness?

Answer 12

Brittleness describes the property of a material that when stressed, fractures without deforming first

Question 13

What are joints?

Answer 13

Joints are structures that connect 2 structures together

Question 14

What are fixed joints?

Answer 14

Joints that are rigid and don’t move

Question 15

What are moveable joints?

Answer 15

Joints that can move

Question 16

What is friction?

Answer 16

Force caused when surfaces of 2 objects rub against each other

Question 17

What are some joints that rely on friction?

Answer 17

1. Nails screw, rivets, tacks, and staples (friction between the metal and the material surrounding it that does the job)
2. Interlocking pieces (increase area of contact->increases friction)
3. Mass (bricks)

Question 18

What are some joints that rely on bonding?

Answer 18

1. Glue, tape, cement, welds (surfaces harden together into 1 solid mass)

Question 19

What are some materials in the human structure? (I don’t think we need to know these but just in case here they are)

Answer 19

Bones - hard and rigid
Cartilage - reduces friction, provides a smooth surface for movement and absorbs shock
Ligaments - bands of strong connective tissue that can join bones together
Tendons - strong and flexible tissue that attaches muscle to bones
Muscles - fibrous tissue that allow bones to move by contracting and relaxing

Question 20

What are the different joints in the human body? (might not need to know but still)

Answer 20

Ball and socket - hips and shoulders
Hinge - elbows and knees
Pivot - spinal column (it twists)
Gliding - wrists

Question 21

What does the skin do in the human structure? (another might not need to know but still)

Answer 21

Provides structural shelter by waterproofing the body and protects it from bacteria. Skin also regulates body temperature.

Question 22

_______, _______, and _______ rely on the proper use of materials

Answer 22

Stability, strength and function rely on the proper use of materials

Question 23

What is a margin of safety?

Answer 23

The limits within a structure’s safety performance is considered to be acceptable (speed limits, weight limits, etc)

Question 24

How can the margin of safety be found out?

Answer 24

1. Through safety testing - using greater than normal forces to see when it fails
2. Through people looking to see how often the structure fails and why

Question 25

What are the environmental factors that need to be noted when building?

Answer 25

1. Climatic conditions - severe heat, wind, rain, cold, and snow
2. Terrain conditions - soil stability, steep terrain, low lying areas
3. Earthquake risks - being able to withstand the external and internal forces that may act on them

Question 26

What is corrugation?

Answer 26

Corrugation is the process of forming a material into wave-like ridges or folds. The waves could also only be in the middle of a flat surface

Question 27

What is lamination?

Answer 27

Lamination is the process of putting a harder and sturdier substance on something weaker to make it sturdier

Question 28

How could you add strength to a material without corrugation or lamination?

Answer 28

1. Make greater use of trusses and arches

2. Change methods of fastening - instead of seams, zippers, or buckles use tape, sewing, or gluing

Question 29

What factors need to be considered when designing an object?

Answer 29

Cost, benefits, safety, and impact on the environment