Unit D Lesson D17 Improving Materials and Sructures
Completion requirements
Lesson D17: Improving Materials and Structures
Video Lesson
Scientists constantly are developing new materials to help make structures better. Watch this video to learn more about how various materials are used to improve structures.
Lesson D17: Improving Materials and Structures
Figure D.4.17.1 – Snowshoeing is a fun way to stay active during the winter.
Reading and Materials for This Lesson
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 324–328
Materials:
thin plastic bags, parchment paper, scissors, iron, ironing board
Traditional and Modern Snowshoes
If you step into deep snow during the winter, your feet sink into the snow, which makes walking difficult. Snowshoes are frame structures that spread the force from a persons body over a larger area of snow, allowing the person to walk on top of the snow.
First Nations peoples in Canada used snowshoes during the winter so they could walk on deep snow and hunt and trap animals. Traditional First Nations snowshoes were outlined with curved wood and covered with a web made of rawhide (strips of animal skin). Snowshoes were tied to the persons feet with leather straps. Traditional snowshoes had to be waxed and maintained often so the rawhide and wood did not dry out and crack.
Modern snowshoes are made with tubes of aluminum or stainless steel and plastic, which makes them light. They have sharp, ridged cleats on the bottom to prevent slipping on ice. Modern snowshoes do not need to be maintained, and they are less awkward to use than traditional snowshoes are.
If you step into deep snow during the winter, your feet sink into the snow, which makes walking difficult. Snowshoes are frame structures that spread the force from a persons body over a larger area of snow, allowing the person to walk on top of the snow.
First Nations peoples in Canada used snowshoes during the winter so they could walk on deep snow and hunt and trap animals. Traditional First Nations snowshoes were outlined with curved wood and covered with a web made of rawhide (strips of animal skin). Snowshoes were tied to the persons feet with leather straps. Traditional snowshoes had to be waxed and maintained often so the rawhide and wood did not dry out and crack.
Modern snowshoes are made with tubes of aluminum or stainless steel and plastic, which makes them light. They have sharp, ridged cleats on the bottom to prevent slipping on ice. Modern snowshoes do not need to be maintained, and they are less awkward to use than traditional snowshoes are.
Figure D.4.17.2 – Traditional First Nations snowshoes made from wood and rawhide.
Figure D.4.17.3 – Modern snowshoes made from stainless steel and plastic.
Changing Telephones
Telephone design has changed much since its invention 140 years ago. Early telephones had a separate speaker and microphone. People had to talk to a switchboard operator to connect them to the person they wanted to call. Later, automatic dialing was developed. Until cell phones and cordless phones were invented, every telephone was attached to a telephone line with a cord, and roads and streets had wires strung on poles connected to the switchboards.
In 1973, Martin Cooper made the first cell phone call although cell phones did not become widely used until the late 1990s. Early cell phones were used only for making phone calls. Features such as texting, cameras, and Wifi access were added gradually, turning cell phones into mobile electronic devices.
Telephone design has changed much since its invention 140 years ago. Early telephones had a separate speaker and microphone. People had to talk to a switchboard operator to connect them to the person they wanted to call. Later, automatic dialing was developed. Until cell phones and cordless phones were invented, every telephone was attached to a telephone line with a cord, and roads and streets had wires strung on poles connected to the switchboards.
In 1973, Martin Cooper made the first cell phone call although cell phones did not become widely used until the late 1990s. Early cell phones were used only for making phone calls. Features such as texting, cameras, and Wifi access were added gradually, turning cell phones into mobile electronic devices.
Figure D.4.17.4 – Early cell phones were much bulkier than today's.
Figure D.4.17.5 – Telephones in the early 1900s needed two hands.
Figure D.4.17.6 – Telephone numbers used to be dialed into phones.
Watch More
Watch this video to learn more about how telephones have changed over time.
Watch this video to learn the story of the first cell phone call ever made.
Controversial Cell Phones
Cell phone design has improved over the years from big boxy phones to thin light phones that can fit in a pocket. This is largely because computer chips and electric wires inside cell phones have been made smaller.
Coltan is a mineral that conducts electricity very well in small electric circuits. For this reason, coltan is used in cell phones and most other modern electronic devices such as laptops and video game systems.
Much of the worlds coltan is mined in the Democratic Republic of Congo in Africa although it is produced in some other countries, too.
Although coltan is a good material, coltan mining has some downsides.
Figure D.4.17.7 – Electric circuits in cell phones are tiny.
- Endangered mountain gorilla habitats are destroyed as more land is cleared for mining coltan from the ground.
- Wars have been occurring in the Congo for many years. Recent fighting is over coltan mining. People can make lots of money by selling coltan for electronics. Innocent people are hurt by the violence during wars.
- Some young children do not go to school. Instead, they work in coltan mines.
Figure D.4.17.8 – The Eastern Mountain Gorilla is in danger of becoming extinct.
Figure D.4.17.9 – Mining destroys gorilla habitats.
Figure D.4.17.10 – Wars in the Congo have forced people from their villages and into refugee camps.
Connections
Figure D.4.17.11 – A loom is a structure used to weave fibres into fabric.
Figure D.4.17.12 – Weaving with small elastics is a popular childrens craft.
Connections: Technology
>> Weaving Fibres into Fabrics
Humans all over the world have been weaving thin fibres into stronger fabrics for thousands of years. For many years, only fibres from natural sources such as silk, wool, and cotton were used to weave stronger fabrics. Fabrics are used in structures such as clothing and portable homes such as tents.
Today, scientists are developing new types of fibres and weaving them into strong fabrics. Carbon fibre is lightweight yet very strong. It is used in high-speed transportation structures such as new airplanes, racing cars, and racing bicycles. Less weight allows the structure to move faster. Carbon fibre also is used in sports equipment such as hockey sticks and tennis rackets. Because carbon fibre is lighter than other materials, athletes can swing sticks or rackets at higher speeds.
Other new fibres are used to make bullet-resistant and heat-resistant fabrics. These are useful to protect police officers and firefighters while they work.
>> Weaving Fibres into Fabrics
Humans all over the world have been weaving thin fibres into stronger fabrics for thousands of years. For many years, only fibres from natural sources such as silk, wool, and cotton were used to weave stronger fabrics. Fabrics are used in structures such as clothing and portable homes such as tents.
Today, scientists are developing new types of fibres and weaving them into strong fabrics. Carbon fibre is lightweight yet very strong. It is used in high-speed transportation structures such as new airplanes, racing cars, and racing bicycles. Less weight allows the structure to move faster. Carbon fibre also is used in sports equipment such as hockey sticks and tennis rackets. Because carbon fibre is lighter than other materials, athletes can swing sticks or rackets at higher speeds.
Other new fibres are used to make bullet-resistant and heat-resistant fabrics. These are useful to protect police officers and firefighters while they work.
Figure D.4.17.13 – Very small carbon fibres are produced from carbon atoms.
Figure D.4.17.14 – Carbon fibres are woven into strong lightweight material.
Watch More
Kevlar Fibre
Kevlar is a type of fibre used to make bullet-resistant and heat-resistant fabric. Watch this video to find out more about the uses for Kevlar.
Kevlar is a type of fibre used to make bullet-resistant and heat-resistant fabric. Watch this video to find out more about the uses for Kevlar.
This video shows how Kevlar is much stronger than natural materials such as cotton and leather.
Some new high-tech fabrics have small electric wires woven into the fabric to sense heart rate, breathing, and movement. Watch this video to learn more.
Connections
Connections: Environment
>> Eco-Friendly House Materials
Eco-friendly materials used in house construction use less energy.
For example, scientists are trying to develop a new type of concrete with the help of bacteria. This concrete does not need a lot of heat energy to be made, unlike traditional concrete
Recycled materials also are being used to build structures. This reduces waste in landfills. For example, materials such as scrap metal can be melted and reused for wires and pipes.
Old denim blue jeans can even be recycled into house insulation!
>> Eco-Friendly House Materials
Eco-friendly materials used in house construction use less energy.
For example, scientists are trying to develop a new type of concrete with the help of bacteria. This concrete does not need a lot of heat energy to be made, unlike traditional concrete
Recycled materials also are being used to build structures. This reduces waste in landfills. For example, materials such as scrap metal can be melted and reused for wires and pipes.
Old denim blue jeans can even be recycled into house insulation!
Figure D.4.17.16 – Scrap metal can be recycled into useful structures again.
Watch More
Bacteria-Made Cement
This video shows how brick mortar is made with the help of bacteria.
This video shows how brick mortar is made with the help of bacteria.
Watch More
Watch this video to see how denim fabric is recycled into insulation.
Try It!
Fused Plastic Material
Try making a strong plastic material from recycled plastic bags.
Materials:
Try making a strong plastic material from recycled plastic bags.
Materials:
- thin plastic bags
- parchment paper (used for baking)
- scissors
- clothes iron
- ironing board
Safety Warning
This activity must be completed with the supervision of an adult who has experience using an iron. DO NOT attempt this activity by yourself.
A hot iron can burn you or others. It can start a fire if you are not careful.
Never leave a hot iron unattended. Unplug the iron immediately after you have finished using it.
Never leave the hot surface of an iron face down on a surface.
A hot iron can burn you or others. It can start a fire if you are not careful.
Never leave a hot iron unattended. Unplug the iron immediately after you have finished using it.
Never leave the hot surface of an iron face down on a surface.
Instructions:
This video shows the process of making fused plastic material.
This video shows the process of making fused plastic material.
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Cut the handles and bottom from the plastic bags.
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Turn any labels on the bags to the inside, away from the surface.
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Layer plastic bags so that you have 8 layers of thin plastic. You can fold one bag to make a small piece of material, or you can layer 8 bags to make a big piece of material.
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Cover the plastic layers completely with parchment paper.
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Iron over the parchment paper. The iron should never touch a plastic bag. Keep the iron moving for about 15 seconds.
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Lift the parchment paper, turn the plastic layers over, and put the parchment paper back on top. Iron over the parchment paper again.
- Unplug the iron and let the plastic cool.
Questions:
You can use the fused plastic material to make something creative. If you know how to sew, could you make a structure such as a strong bag or a wallet? Could you use the material to build another structure?
Lamination is the process of making a material from layers. You melted the layers of plastic together to join them into a laminate.
In some ways, the fused material is better than a regular plastic bag. It does not tear or stretch as easily as a regular plastic bag does. However, in other ways, a thin plastic bag is better than the fused material. A thin plastic bag is reasonably
strong, but it is lighter than the fused material. It does not add extra weight to the load in the bag.
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 17 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.
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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!
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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.
Both aluminum and wood are strong, but aluminum is lighter than wood. Reducing weight in a backpack is an advantage for the hiker.
Aluminum is a lighter metal than stainless steel is. Choosing an aluminum pot reduces weight in a backpack and makes carrying over long distances easier.
Single fibres are easier to break than a woven fabric is. If one fibre breaks in the fabric, the entire piece of fabric does not fall apart.
New televisions are much thinner than the old ones were. Old televisions did not use computer chips to operate. New televisions use small computer chips and liquid crystal display screen, which allows the design of the television to be much
thinner.
Nylon is much stronger and does not break as easily as plant fibres do, which makes nylon ropes stronger.