Unit D Lesson D11 Material Properties
Completion requirements
Lesson D11: Material Properties
Video Lesson
Understanding the properties of various materials used in building structures is important so one can choose materials that fit the function of the structure. Watch this video to learn more about the various properties of materials.
Lesson D11: Material Properties
Figure D.3.11.1 – Braces are made from brackets, wires, and elastics.
Figure D.3.11.2 – An orthodontist is a special dentist that installs and adjusts braces.
Flexible Braces
Many young teenagers wear braces to straighten their teeth. Do you know anyone who wears braces?
A main material used in braces is stainless steel wire. An important property of such wires is ductility; the wire must be bent to fit the persons specific set of crooked teeth.
Brackets are glued to the persons teeth, and a wire is tightened through all the brackets. Sometimes, little elastics are used to fasten the wire to the brackets. Force from the tight wire causes the teeth to move! An orthodontist (a special type of dentist) bends and moves the ductile wire usually once a month to readjust where the force is being applied to the teeth.
Many young teenagers wear braces to straighten their teeth. Do you know anyone who wears braces?
A main material used in braces is stainless steel wire. An important property of such wires is ductility; the wire must be bent to fit the persons specific set of crooked teeth.
Brackets are glued to the persons teeth, and a wire is tightened through all the brackets. Sometimes, little elastics are used to fasten the wire to the brackets. Force from the tight wire causes the teeth to move! An orthodontist (a special type of dentist) bends and moves the ductile wire usually once a month to readjust where the force is being applied to the teeth.
Reading and Materials for This Lesson
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 308–312
Materials:
drinking straws, masking tape, scissors, large paper clips, paper cup, coins (all the same type), ruler, at least three types of string such as thread, dental floss, cooking twine, or yarn
Watch More
Braces Time-Lapse
Watch this time-lapsed video to see how force from the wire in braces straighten teeth over time. (What you see in half a minute might take three years!)
Watch this time-lapsed video to see how force from the wire in braces straighten teeth over time. (What you see in half a minute might take three years!)
Hockey Stick Game
To learn more about the best materials used in making hockey sticks, click here to play a game. In this game, you test several kinds of hockey sticks to discover which material makes the best hockey stick. The game requires free registration at the website, but if you don't want to register, that's OK, playing the game is optional.
To learn more about the best materials used in making hockey sticks, click here to play a game. In this game, you test several kinds of hockey sticks to discover which material makes the best hockey stick. The game requires free registration at the website, but if you don't want to register, that's OK, playing the game is optional.
Figure D.3.11.3 – Hockey sticks are made from various types of materials.
Figure D.3.11.4 – Hockey sticks are made from various types of materials.
Super Strong Glass
Glass is a very useful material because it is waterproof, a good insulator, and usually transparent (allowing us to see through it). When glass is made, it is a hot molten liquid that can poured and molded into almost any shape.
Another good thing about glass is that the primary ingredient for it is sand; therefore, many types of glass are inexpensive to make. The downside to glass is that most types are brittle, which means glass breaks easily.
Glass in vehicles and on high rise buildings must be strong enough to withstand heavy impacts. Safety glass is made of several layers of glass and adhesives. Because of this it is sometimes referred to as a "glass sandwich". Safety glass is not used in hockey arenas. Instead, transparent plastic sheets protect spectators from flying pucks.
Glass is a very useful material because it is waterproof, a good insulator, and usually transparent (allowing us to see through it). When glass is made, it is a hot molten liquid that can poured and molded into almost any shape.
Another good thing about glass is that the primary ingredient for it is sand; therefore, many types of glass are inexpensive to make. The downside to glass is that most types are brittle, which means glass breaks easily.
Glass in vehicles and on high rise buildings must be strong enough to withstand heavy impacts. Safety glass is made of several layers of glass and adhesives. Because of this it is sometimes referred to as a "glass sandwich". Safety glass is not used in hockey arenas. Instead, transparent plastic sheets protect spectators from flying pucks.
Figure D.3.11.5 – Hot molten glass can be twisted and molded.
Figure D.3.11.6 – Safety glass is used in applications where glass is wanted, but added strength in required.
Figure D.3.11.7 – Glass can be shaped into beautiful artistic objects.
Figure D.3.11.8 – The Calgary Tower, the tall tower seen here on the left side of the photo, allows for spectacular views east, west, north, south... and down!
A Transparent Floor in the Calgary Tower
Somewhat surprisingly, some types of glass are very strong, even strong enough for people to stand on! The Calgary Tower has a glass floor as its observation deck. Why is this glass floor so strong?
Somewhat surprisingly, some types of glass are very strong, even strong enough for people to stand on! The Calgary Tower has a glass floor as its observation deck. Why is this glass floor so strong?
Figure D.3.11.8 – Calgary Tower Glass Floor.
Glass can be made stronger and less brittle by heating it to high temperatures and then cooling the outer surface of the glass very fast. This is called tempered glass.
Laminating layers of glass can also make glass stronger. Laminated glass is made from sheets of glass with a thin plastic film between the layers. If one sheet of glass breaks, the entire slab is not affected. This layering method often is used in protective applications; bulletproof glass and car windshields are examples.
The Glacier Skywalk in Jasper National Park opened in 2014. It is a cantilever structure with a glass floor high above the Sunwapta Valley.
Laminating layers of glass can also make glass stronger. Laminated glass is made from sheets of glass with a thin plastic film between the layers. If one sheet of glass breaks, the entire slab is not affected. This layering method often is used in protective applications; bulletproof glass and car windshields are examples.
The Glacier Skywalk in Jasper National Park opened in 2014. It is a cantilever structure with a glass floor high above the Sunwapta Valley.
Figure D.3.11.10 – Bulletproof glass can resist many bullets before it fails.
Figure D.3.11.11 – The Glacier Skywalk in Jasper National Park.
Watch More
Glacier Skywalk in Jasper
Watch this video to walk on the glass floor of the Glacier Skywalk.
Watch this video to walk on the glass floor of the Glacier Skywalk.
Connections
Connections: Technology
>> New Kinds of Glass
Because glass is such a useful material, engineers wanted to determine how to make it less stiff and breakable. In the past few years, they designed a product called Gorilla Glass, which is a thin, strong, and lightweight type of glass.
Now, Gorilla Glass is used on smartphones and tablets as in Figure D.3.11.12 because it does not scratch or break as easily as regular glass does.
>> New Kinds of Glass
Because glass is such a useful material, engineers wanted to determine how to make it less stiff and breakable. In the past few years, they designed a product called Gorilla Glass, which is a thin, strong, and lightweight type of glass.
Now, Gorilla Glass is used on smartphones and tablets as in Figure D.3.11.12 because it does not scratch or break as easily as regular glass does.
Figure D.3.11.12 – The surface of smartphones is made from Gorilla Glass.
Watch More
Watch this video to see some experiments showing the production and strength of Gorilla Glass.
Optical Fibre
Ordinary glass is brittle and stiff. You might not think that glass can be flexible, but it is! Flexible glass is very important for structures such as fibre optic cables, which are needed for the Internet.
Ordinary glass is brittle and stiff. You might not think that glass can be flexible, but it is! Flexible glass is very important for structures such as fibre optic cables, which are needed for the Internet.
Figures D.3.11.13 – Fibre optic cables are cords made of flexible glass tubes. Figure on left by
Hhedeshian.
Watch this video to see flexible glass in action.
Board Laminates
Skateboards are made from laminated thin layers of wood. Laminated wood is used in skateboards because it is lightweight and allows for a lip on the skateboard to be bent up at either end. The skateboard lip is necessary for riders to do tricks and to stop their boards.
Skateboards are made from laminated thin layers of wood. Laminated wood is used in skateboards because it is lightweight and allows for a lip on the skateboard to be bent up at either end. The skateboard lip is necessary for riders to do tricks and to stop their boards.
Figure D.3.11.14 – Laminated wood skateboards.
Watch More
Building Skateboards
Watch this video to see how skateboards are made.
Watch this video to see how skateboards are made.
Try It!
Materials Testing
Scientists discover the properties of materials through experiments. Try this simple experiment to test the strength of various types of string.
Materials:
Scientists discover the properties of materials through experiments. Try this simple experiment to test the strength of various types of string.
Materials:
- drinking straws
- masking tape
- scissors
- large paper clips
- paper cup
- coins (all the same type)
- ruler
-
at least three different types of string, such as thread, dental floss, cooking twine, yarn
Instructions:
-
Follow the directions on
this website to build a suspension bridge. Or if you like, you don't have to follow the instructions, you can build a suspension bridge completely on your own. Make your first bridge with your thinnest type of string.
-
Add coins to the paper cup until the bridge collapses. Record the number of coins.
- Repeat Steps 1 and 2 to make and test suspension bridges for each of your types of string.
Questions:
Think about the following questions very carefully. Then, type or write your answers. When you have your answers, click the questions for feedback.
Think about the following questions very carefully. Then, type or write your answers. When you have your answers, click the questions for feedback.
Any string made of multiple strands twisted together was probably the strongest type of string for your suspension bridge. With twisted string, if a failure occurs in one part of the string, the other strands help carry the load without the structure
failing.
Suspension bridges use twisted wire cables so that, if one small wire breaks, the other wires in the cable still work together to hold up the bridge.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to
guide your learning.
Unit D Lesson 11 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps – if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
- DOWNLOAD the self-check quiz by clicking here.
- ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
- COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
-
REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
- SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
- CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum, or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Self-Check Time!
|
Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.
Gold is rare, which means it has low availability. This means gold is expensive. Therefore, people choose to make electrical wires from cheaper, more available copper rather than from gold.
A person might choose bamboo over granite for several reasons. He or she might like the aesthetics (appearance) of bamboo more than those of granite. He or she might choose bamboo because it is more environmentally-friendly than granite is.
Bamboo is a renewable resource that can be re-grown. Much less energy from fossil fuels is used to harvest and prepare bamboo than is used to mine and prepare granite.
In a small compact car, the most important consideration for the passenger compartment materials is stiffness. The metals and plastics must resist deformation in a collision. If the metals and plastics are stiff, the passenger cabin will not
crumple easily. This keeps the passengers safe.
A garden hose must be stiff enough to resist deformation from the force of water running through it. The hose must be flexible so it can be moved to places the person wants to use it without the hose breaking.
You could make a laminate from layers of fabric. If one layer of fabric rips or breaks, a hole would not necessarily appear through the total fabric. Another way could be to use a mesh (grid) of stronger fibres (even metal) among the weave of
the cloth.