Unit D Lesson D14 Protective Structures
Completion requirements
Lesson D14: Protective Structures
Video Lesson
Many natural and human-made structures have designs that provide protection. Watch this video to learn more about some interesting protective structures.
Lesson D14: Protective Structures
Layers that Protect
One of the most common protective structures is a layer that keeps out environmental conditions. Trees use bark to protect themselves from invaders and to prevent water from evaporating as it moves up to the leaves. Fish and reptiles have scales that act like armor. Mammals have fur and hair that regulate temperature.
Human skin is a structure that protects us from many outside dangers, and also contains our important internal processes. One of our skin's most important functions is to block harmful solar radiation from reaching delicate tissues inside our body.
One of the most common protective structures is a layer that keeps out environmental conditions. Trees use bark to protect themselves from invaders and to prevent water from evaporating as it moves up to the leaves. Fish and reptiles have scales that act like armor. Mammals have fur and hair that regulate temperature.
Human skin is a structure that protects us from many outside dangers, and also contains our important internal processes. One of our skin's most important functions is to block harmful solar radiation from reaching delicate tissues inside our body.
Reading and Materials for This Lesson
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 320–323
Materials:
cardboard, masking tape, hair dryer, glass jar, tin foil, rubber band, pin, coins, ice cube, plastic wrap, plastic bags, cotton balls, Styrofoam trays, popsicle sticks
Figure D.3.14.1 – The plumed basilisk has skin that helps camouflage the lizard as it hunts.
Figure D.3.14.2 – Applying sunscreen to your skin can help prevent sunburns.
Connections
Connections: Health and Wellness
>> Skin Safety
Skin is the most important protective structure of the human body.
Sun rays and heat can damage skin. Severe sunburns can result in painful redness and blistering of the skin, as seen in Figure D.3.14.3. Repeated sunburns can lead to skin cancer, which is why staying in the shade and using sunscreen is important if you plan to spend time outdoors on very sunny days.
Situations involving extreme heat, such as spilled boiling water and stovetop fires, can cause severe skin burns. Handling hot water and other hot liquids carefully is very important. Never leave a hot stove unattended, especially if you are cooking with oil.
>> Skin Safety
Skin is the most important protective structure of the human body.
Sun rays and heat can damage skin. Severe sunburns can result in painful redness and blistering of the skin, as seen in Figure D.3.14.3. Repeated sunburns can lead to skin cancer, which is why staying in the shade and using sunscreen is important if you plan to spend time outdoors on very sunny days.
Situations involving extreme heat, such as spilled boiling water and stovetop fires, can cause severe skin burns. Handling hot water and other hot liquids carefully is very important. Never leave a hot stove unattended, especially if you are cooking with oil.
Figure D.3.14.3 – Sunburns can cause painful blistering and peeling of the skin
Connections
Connections: Technology
>> Growing Artificial Human Skin
Severe skin burns destroy skin cells completely. To repair skin burns, surgeons sometimes graft skin. That is, they cut healthy skin from the victim and sew it over the burn wounds. Skin grafting works, but its not an ideal treatment because it causes wounds on healthy skin.
Scientists are finding ways to grow new human skin from skin cells. They are even working on a way to print skin using a 3-D printer!
Watch this video to see how 3-D printed skin is made!
>> Growing Artificial Human Skin
Severe skin burns destroy skin cells completely. To repair skin burns, surgeons sometimes graft skin. That is, they cut healthy skin from the victim and sew it over the burn wounds. Skin grafting works, but its not an ideal treatment because it causes wounds on healthy skin.
Scientists are finding ways to grow new human skin from skin cells. They are even working on a way to print skin using a 3-D printer!
Watch this video to see how 3-D printed skin is made!
Your Personal Air Conditioner and Insulator
Your skin keeps your body temperature just right. Skin contains special nerve cells that detect temperature.
When your body is cold, your skin temperature detectors tell your body to send more warm blood to the surface. In addition, messages are sent to your body muscles, which start shivering to produce heat.
When your body is hot, your skin temperature detectors send messages to your sweat glands. Your sweat glands open and release moisture onto your skin. Sweat evaporating from your skin helps you to feel cooler.
Your skin keeps your body temperature just right. Skin contains special nerve cells that detect temperature.
When your body is cold, your skin temperature detectors tell your body to send more warm blood to the surface. In addition, messages are sent to your body muscles, which start shivering to produce heat.
When your body is hot, your skin temperature detectors send messages to your sweat glands. Your sweat glands open and release moisture onto your skin. Sweat evaporating from your skin helps you to feel cooler.
Figure D.3.14.4 – Do you get "goose bumps", "goose pimples", or "goose flesh" when you get cold?
Figure D.3.14.5 – Shivering helps your body keep warm in cold weather.
Figure D.3.14.6 – Sweating cools your body when you feel hot.
Connections
Connections: Technology
>> Skin-Inspired Building Exteriors
Buildings with lots of glass windows, such as the one in Figure D.3.14.8, become very warm on sunny days. This is useful during cold winters, but it is a problem during hot summers. On hot days, buildings need air conditioning so people can live and work in them comfortably. On extremely hot days, so much electricity is used for air conditioning that brownouts occur. Electricity companies must reduce the flow of electricity in the power grid so that all customers receive some. If the electricity supply is less than demand, someone is left completely in the dark (or in the heat) – and that's a blackout.
Architects are trying to develop structures on buildings that provide natural air conditioning similar to the way human skin provides it. These air conditioning structures do not need electricity to work because they are made from a special bending laminated metal.
>> Skin-Inspired Building Exteriors
Buildings with lots of glass windows, such as the one in Figure D.3.14.8, become very warm on sunny days. This is useful during cold winters, but it is a problem during hot summers. On hot days, buildings need air conditioning so people can live and work in them comfortably. On extremely hot days, so much electricity is used for air conditioning that brownouts occur. Electricity companies must reduce the flow of electricity in the power grid so that all customers receive some. If the electricity supply is less than demand, someone is left completely in the dark (or in the heat) – and that's a blackout.
Architects are trying to develop structures on buildings that provide natural air conditioning similar to the way human skin provides it. These air conditioning structures do not need electricity to work because they are made from a special bending laminated metal.
Figure D.3.14.7 – Air conditioners help keep buildings cool on hot days
Figure D.3.14.8 – Sunlight enters a building through windows and warms the building.
Watch More
Breathable Buildings
Watch this video to see how skin-inspired air-conditioning structures work. The ideas are very complex, but someday you might live or work in a building so equipped.
Watch this video to see how skin-inspired air-conditioning structures work. The ideas are very complex, but someday you might live or work in a building so equipped.
Protective Houses
Houses contain many structures that protect people.
In Canada, insulation in house walls reduces temperature changes. Insulation traps heat inside houses during the winter. A protective layer of polyethylene (plastic film) is essential on the warm side of the insulation to prevent the movement of air and moisture into the insulation. Also, insulation helps to keep heat out of houses during the summer.
In climates where the ground freezes during winter, such as Canada, houses have concrete basements. Freezing ground expands and pushes upward. Thawing ground in the spring moves back downward. Concrete basement foundations provide protection against the up-and-down motion from the ground freezing and thawing – and the houses remain stable and solid.
Waterproof shingles are used on roofs to protect homes from rain, hail, and snow.
In Canada, insulation in house walls reduces temperature changes. Insulation traps heat inside houses during the winter. A protective layer of polyethylene (plastic film) is essential on the warm side of the insulation to prevent the movement of air and moisture into the insulation. Also, insulation helps to keep heat out of houses during the summer.
In climates where the ground freezes during winter, such as Canada, houses have concrete basements. Freezing ground expands and pushes upward. Thawing ground in the spring moves back downward. Concrete basement foundations provide protection against the up-and-down motion from the ground freezing and thawing – and the houses remain stable and solid.
Waterproof shingles are used on roofs to protect homes from rain, hail, and snow.
Figure D.3.14.8 – Insulation is installed into the walls of houses.
Figure D.3.14.9 – Many houses in Canada have concrete foundations.
Figure D.3.14.10 – Shingles stop water from soaking through wood roofs.
Try It!
Protective Home Models
Houses in various climates require different protective features. In this activity, you will design and build model houses for three climates in Canada.
Materials:
Houses in various climates require different protective features. In this activity, you will design and build model houses for three climates in Canada.
Materials:
- cardboard
- masking tape
- hair dryer
- glass jar
- aluminum foil
- rubber band
- pin
- coins
- ice cube
- plastic wrap
- plastic bags
- cotton balls
- Styrofoam trays
- popsicle sticks
-
any other building materials you think might be useful
Instructions:
House for Vancouver, British Columbia
Vancouver has a temperate rainforest climate, which is neither very hot nor very cold and it rains a lot. Houses in Vancouver must be able to withstand the rain.
Vancouver has a temperate rainforest climate, which is neither very hot nor very cold and it rains a lot. Houses in Vancouver must be able to withstand the rain.
-
Using materials of your choice, design and build a model house with protective structures to fit the rainy climate of Vancouver, BC.
-
Test the your house with rain without sprinkling water on your model. Instead, put a piece of aluminum foil over the top of a glass jar and fasten it with a rubber band. Use a pin to punch tiny holes in the foil. Sprinkle water (rain) on your house.
- If the jar does not get wet on the inside, your house passes the rain test.
Figure D.3.14.11 – Vancouver
House for Milk River, Alberta
Milk River, in southern Alberta, has a dry climate. Summers are very hot, around 30°C, and winters are very cold, around –20°C. Milk River is often windy.
Milk River, in southern Alberta, has a dry climate. Summers are very hot, around 30°C, and winters are very cold, around –20°C. Milk River is often windy.
-
Using materials of your choice, design and build a model house with protective structures to fit the hot, windy climate of Milk River, AB.
-
Test your house with wind and heat. Put an ice cube inside the house. Blast the house with hot air from a hair dryer for several minutes.
- If the ice cube does not melt, and the house does not fall down, the house passes the heat and wind test.
Figure D.3.14.12 – Milk River
House for Quebec City, Quebec
Quebec City is one of the snowiest cities in Canada.
Quebec City is one of the snowiest cities in Canada.
-
Using materials of your choice, design and build a model house with protective structures to fit the snowy climate of Quebec City, QC.
-
Test your house with snow weight. Place coins on top of the roof.
- If the roof can hold 50 coins without collapsing, it passes the snow test.
Figure D.3.14.13 – Quebec City
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 14 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.
Clay tiles are brittle and break easily. The force from falling hail might break clay tiles, which ruins their protective ability.
A thick waxy outer coating on plants stops water from leaving the plant. This is very important in dry climates where rain is rare and plants need to retain water to live.
Thorns and prickles prevent animals from eating the plant, so the plant can survive and grow.
The hard skull surrounds and protects the soft tissues of the brain. Because the brain sends messages to the remainder of the body, the body cannot function adequately if the brain is injured.
Dogs have fur that acts as insulation. Fur keeps dogs warmer in cold weather and cooler in hot weather. Also, dogs have thick padding on their paws; this protects their paws from sharp surfaces or cold surfaces.