Unit B Lesson B8 The Role and Use of Plants
Completion requirements
Lesson B8: The Role and Use of Plants
Video Lesson
People use plants for many purposes. Watch the video below to learn about the important roles that plants have in people’s lives.
Lesson B8: The Role and Use of Plants
Figure B.2.8.1 – Cacao pods are the large fruit of the cacao tree.
Figure B.2.8.2 – Cacao pods contain cocoa beans.
Money Does Grow on Trees
Likely, you have heard the expression, “Money doesn’t grow on trees” -- especially from a parent when you need some cash! However, cacao beans were used by Indigenous Central American people as money. Cacao beans grow on trees. Cacao trees grow fruit pods containing beans, which are the plant’s seeds. Cacao seeds can be fermented, dried, roasted, and ground to make cocoa powder and chocolate. (Notice the spelling of the cacao tree and the cocoa beans and powder -- and they are pronounced differently, too!)
Cacao trees originally are from Central and South America, but today most of the world’s chocolate is grown in West African countries.
Likely, you have heard the expression, “Money doesn’t grow on trees” -- especially from a parent when you need some cash! However, cacao beans were used by Indigenous Central American people as money. Cacao beans grow on trees. Cacao trees grow fruit pods containing beans, which are the plant’s seeds. Cacao seeds can be fermented, dried, roasted, and ground to make cocoa powder and chocolate. (Notice the spelling of the cacao tree and the cocoa beans and powder -- and they are pronounced differently, too!)
Cacao trees originally are from Central and South America, but today most of the world’s chocolate is grown in West African countries.
Figure B.2.8.3 – Cocoa beans are fermented, dried, roasted, and ground to make cocoa powder.
Reading and Materials for This Lesson
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 126–132
Materials:
sunflower seeds with the shells removed, mortar and pestle, water, plastic wrap, 3 cooking pots, 3 bowls, 2 cups yellow onion skins, 2 cups chopped purple cabbage, 4 tbsp ground turmeric, mesh strainer, white vinegar, 3 or more hard-boiled eggs,
tongs, paper towels
Watch More
How Is Chocolate Made?
Watch this video to learn about cacao trees and cacao beans.
Watch this video to learn about cacao trees and cacao beans.
Watch this video to learn more about chocolate coming from plants.
Connections
Connections: Technology
>> Biofuels
Fuels are substances that we burn to produce heat, movement, and electricity. In the last 150 years, humans have used mostly fossil fuels such as coal, oil, and natural gas. Fossil fuels form from plants and animals that died millions of years ago. Because fossil fuels take a very long time to form, Earth has a limited supply of them. The supplies of fossil fuels eventually will be used. Scientists are searching for different types of fuels we can use to produce electricity, drive cars and airplanes, and heat homes and buildings.
Biofuels can be made faster than fossil fuels were. Biofuels are made from plants that grow quickly.
Ethanol is a biofuel that often is added to car gasoline. Ethanol is made by fermenting sugar, which can be obtained from several sources such as corn, sugarcane, sugar beets, sweet sorghum, cassava, and wheat.
Biodiesel is used in airplanes and some vehicles. Biodiesel is made from vegetable oils from oil palm, coconut, canola, peanuts, sunflowers, and soybeans.
>> Biofuels
Fuels are substances that we burn to produce heat, movement, and electricity. In the last 150 years, humans have used mostly fossil fuels such as coal, oil, and natural gas. Fossil fuels form from plants and animals that died millions of years ago. Because fossil fuels take a very long time to form, Earth has a limited supply of them. The supplies of fossil fuels eventually will be used. Scientists are searching for different types of fuels we can use to produce electricity, drive cars and airplanes, and heat homes and buildings.
Biofuels can be made faster than fossil fuels were. Biofuels are made from plants that grow quickly.
Ethanol is a biofuel that often is added to car gasoline. Ethanol is made by fermenting sugar, which can be obtained from several sources such as corn, sugarcane, sugar beets, sweet sorghum, cassava, and wheat.
Biodiesel is used in airplanes and some vehicles. Biodiesel is made from vegetable oils from oil palm, coconut, canola, peanuts, sunflowers, and soybeans.
Figure B.2.8.4 – Cocoa beans are fermented, dried, roasted, and ground to make cocoa powder.
Figure B.2.8.5 – Biofuels are made from corn.
Watch More
Biofuels
The production of biofuels still has some problems. For example, limited farm space is available to grow corn, which requires good soil and hot sunshine with appropriate rainfall. Of course, crops used for ethanol are also food crops. Thus “Do we eat it or put it into our cars?” becomes a significant question.
Scientists are working on new biofuels that can be made with plants other than corn. Watch this video to learn more.
The production of biofuels still has some problems. For example, limited farm space is available to grow corn, which requires good soil and hot sunshine with appropriate rainfall. Of course, crops used for ethanol are also food crops. Thus “Do we eat it or put it into our cars?” becomes a significant question.
Scientists are working on new biofuels that can be made with plants other than corn. Watch this video to learn more.
Scientists are working constantly on how to make better biofuels. Watch this video to learn how new airplane jet biofuels are developed.
Try It!
Making Biodiesel
Sunflower oil is used in making biodiesel. Try this simple experiment to extract sunflower oil from sunflower seeds.
Materials:
- small handful of sunflower seeds with the shells removed
- mortar and pestle
- water
-
plastic wrap
Instructions:
-
Place the sunflower seeds in the mortar.
-
Use the pestle to crush the sunflower seeds into very small pieces. Crush the seeds until they form a paste.
-
Add some water to the paste of seeds in the mortar so that the mortar is half full.
-
Cover the mortar with plastic wrap and let it sit for 1 or 2 days.
-
Remove the plastic wrap, but do not move or shake the mortar. What do you observe?
Questions:
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
You should have observed small bubbles of oil floating on top of the water. When you crushed the sunflower seeds, oil inside the seeds was released. This is how sunflower oil is extracted from sunflower seeds to make biodiesel.
Figure B.2.8.6 – Henna tattoos are a popular art in some parts of the world.
Figure B.2.8.7 – A completed henna tattoo.
Dyes
People have used dyes for thousands of years to change the colour of fabric or leather. Although some dyes are made from insects and animals, most natural dyes come from plants.
People have used dyes for thousands of years to change the colour of fabric or leather. Although some dyes are made from insects and animals, most natural dyes come from plants.
Henna is a dye that is used to darken skin and hair. Leaves of the henna tree are dried and crushed into a powder. The powder is made into a paste that can be applied to skin. The paste stains skin temporarily, and the temporary tattoo wears off naturally. In many cultures in North Africa, the Middle East, and India, women paint henna designs on their skin for special occasions, such as marriage.
Indigo dye is a dark blue colour. It is used to dye fabric for blue jeans, for example. Although indigo is made in factories now, it used to be made from the fermented leaves of indigo plants.
In Alberta, First Nations made dyes from wild plants to decorate their clothing and bodies. For example, they used the juices from wild saskatoon berries and blueberries to make a purple dye.
Figure B.2.8.8 – Henna leaves are dried and crushed into a powder.
Figure B.2.8.9 – Indigo dye comes from the leaves of indigo plants.
Figure B.2.8.10 – Indigo dye is dark blue.
Watch More
Dyes from Plants
This video shows you indigo plants as well as more examples of plants that are used to make dyes.
This video shows you indigo plants as well as more examples of plants that are used to make dyes.
Try It!
Coloured Eggs
Try this experiment to make dyes from plants. You can use these dyes to make coloured eggshells.
Wear old clothing or an apron while you do this experiment so you do not accidentally ruin good clothes with coloured dye.
Materials:
Wear old clothing or an apron while you do this experiment so you do not accidentally ruin good clothes with coloured dye.
Materials:
- 3 cooking pots
- 3 bowls
- water
- 2 cups yellow onion skins
- 2 cups chopped purple cabbage
- 4 tbsp ground turmeric root
- mesh strainer
- white vinegar
- 3 or more hard-boiled eggs
- tongs
-
paper towels
Safety Warning
This activity involved hot water and dyes that stain. It must be completed with the supervision of an adult.
DO NOT attempt this activity by yourself.
Boiling water can burn you or others if you are not careful.
Never leave a hot stove with hot water unattended.
Turn off the stove immediately after you have finished using it.
DO NOT attempt this activity by yourself.
Boiling water can burn you or others if you are not careful.
Never leave a hot stove with hot water unattended.
Turn off the stove immediately after you have finished using it.
Instructions:
-
To make onion skin dye, combine 2 cups of yellow onion skins with 2 cups water in a cooking pot.
-
To make purple cabbage dye, combine 2 cups of purple chopped cabbage with 2 cups water in a cooking pot.
-
To make turmeric dye, combine 4 tablespoons of ground turmeric with 2 cups water in a cooking pot.
-
We recommend you make one dye at a time, but you and your adult helper might wish to do three at once.
-
Bring the dye pot to a boil on stove burners at medium heat. Turn down the heat and let the dye simmer for 30 minutes.
-
Turn off the heat, and let the dye cool to room temperature.
-
Over a sink, pour the dye through a clean strainer into a bowl. Be careful to use clean equipment and do not mix the dye colours.
-
Add 2 tablespoons of vinegar to each dye bowl.
-
Add a hard-boiled egg (or several eggs) to each bowl of dye. Be sure the eggs are completely covered by the dye.
-
Let the eggs sit in the dye for at least 2 hours, or overnight if you want darker colours.
-
Remove the eggs from the dyes with clean tongs.
-
Dry the eggs with paper towels.
-
Observe the colours!
Figure B.2.8.11 – Cotton fabric is made from cotton plant fibres.
Figure B.2.8.12 – Linen fabric is made from stems of flax plants.
Linen-Wrapped Mummies
People have been using cotton and linen plants for thousands of years to make clothing. Linen is woven from stems of the flax plant. Linen is very cool in hot weather, which is why people in ancient Egypt and Rome wore clothes made from linen. Even Egyptian mummies were wrapped in linen!
To learn more about various types of plants that are used to make clothing, click here to Explore with Elsie.
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 B Lesson 9 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.
Carnivores eat other animals. The animals that are eaten by carnivores are probably herbivores (plant eaters) or omnivores (plant and meat eaters). Herbivores and omnivores must eat plants to survive. Because carnivores need plant-eaters for
food, carnivores are also dependent on plants.
Trees provide shelter for insects, birds, and animals. If the trees die, then insects, birds, and animals more easily are left exposed to predators. Trees also provide food for many living things. If trees die, species that depend on the trees
for food must move elsewhere to survive.
Trees put oxygen into the air. Humans need oxygen for cellular respiration. If trees are cut and not replanted, less oxygen is placed in the air for humans to breathe.
Ice cream is made from milk. Milk comes from cows. Cows are herbivores that eat plants such as grass. If there were no plants, cows would have no food and they would not survive. Without cows for milk, we wouldn’t have ice cream.
You use plants every day in many ways. For example, you eat plants for food. You probably wear clothing made from plants. You might live in a house made of wood. You read books made of paper.