Unit B Lesson B2 How Water Flows in Plants
Completion requirements
Lesson B2: How Water Flows in Plants
Video Lesson
Plants need water to live and thrive. Watch this video to learn more about how water moves to all parts of a plant.
Lesson B2: How Water Flows in Plants
Figure B.1.2.1 – Succulents have thick stems and leaves to store water..
Figure B.1.2.2 – Some giant cacti are as tall as trees.
Plants That Store Extra Water
Some plants thrive in very dry climates. These plants, including cacti, are called succulents. Succulents store lots of sap in their thick, waxy stems. This allows them to survive in places that receive only 5 to 20 centimetres of rain every year.
Succulents make very good house plants -- especially for people who forget to water their plants regularly! Similar to other seed plants, cacti produce flowers. A popular houseplant is the Christmas cactus, which typically blooms in December.
Some plants thrive in very dry climates. These plants, including cacti, are called succulents. Succulents store lots of sap in their thick, waxy stems. This allows them to survive in places that receive only 5 to 20 centimetres of rain every year.
Succulents make very good house plants -- especially for people who forget to water their plants regularly! Similar to other seed plants, cacti produce flowers. A popular houseplant is the Christmas cactus, which typically blooms in December.
Reading and Materials for This Lesson
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 102–103
Materials:
2 large empty plastic pop bottles with lids, scissors, paring knife, 2 plastic plates, petroleum jelly, plastic wrap, small houseplant with leaves, 3 clear plastic or glass cups or jars, water, red and blue food colouring, spoon, 2 paper towels,
cookie sheet or flat shallow pan with a lip, 2 white flowers such as carnations or daisies
Figure B.1.2.3 – Cactus plants have spines instead of leaves.
Figure B.1.2.4 – Cacti produce colourful flowers.
Watch More
Cactus Plants
The stems and fruit of the prickly pear cactus are edible. Watch this video to learn how to eat a prickly pear cactus.
The stems and fruit of the prickly pear cactus are edible. Watch this video to learn how to eat a prickly pear cactus.
This video shows many kinds of cacti and explains how to start a cactus houseplant.
Aloe Vera
Aloe vera is a succulent that many people keep as a houseplant. When you split an aloe vera leaf, you will find a sticky gel. This gel is effective at absorbing water. People spread aloe vera gel on their skin to moisturize dry skin or to soothe sunburns.
Aloe vera is a succulent that many people keep as a houseplant. When you split an aloe vera leaf, you will find a sticky gel. This gel is effective at absorbing water. People spread aloe vera gel on their skin to moisturize dry skin or to soothe sunburns.
Figure B.1.2.5 – Cacti produce colourful flowers.
Figure B.1.2.6 – Cacti produce colourful flowers.
Watch More
Aloe Vera Gel
Watch this video to learn more about the useful properties of aloe vera gel.
Watch this video to learn more about the useful properties of aloe vera gel.
Try It!
Test for Transpiration
Transpiration from plant leaves is very important for adding water to the air. In this experiment, you will observe transpiration in plants.
Materials:
Transpiration from plant leaves is very important for adding water to the air. In this experiment, you will observe transpiration in plants.
Materials:
- 1 small potted houseplant with leaves (small enough to fit inside a large pop bottle)
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2 large empty and dry plastic pop bottles with closed lids (the2-litre size)
- scissors
- 2 plastic plates
- petroleum jelly (Vaseline™)
- plastic wrap (Saran Wrap™)
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small houseplant with leaves that will fit under a pop bottle
Safety Warning
Take care with scissors and knives used for cutting the pop bottles; don't cut yourself or anyone else!
Instructions:
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Cut the bottoms from both pop bottles.
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Wrap carefully the pot of the houseplant tightly with plastic wrap. The surface of the entire pot, including the soil, should be covered – but not the plant!
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Smear petroleum jelly on both plastic plates.
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Put the houseplant on one plate. Cover the houseplant with a pop bottle. The open bottom of the pop bottle should stick into the petroleum jelly on the plate, sealing it effectively.
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Put the other pop bottle into the petroleum jelly on the other plate. This provides a control, or fair test, for the experiment.
- Place both plates and pop bottles near a window with sunlight. Observe after 2 hours.
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.
Nothing should have changed on the empty pop bottle. You should have seen little drops of water on the inside of the pop bottle containing the houseplant. The drops of water were caused by transpiration, or water evaporating from the plant leaves.
Putting plastic wrap around the houseplant pot ensured that this was a fair test.You can be sure that the water drops on the pop bottle were caused by transpiration and not because water evaporated from the houseplant soil.
Figure B.1.2.7 – Rubber comes from the sap of tropical rubber trees.
Figure B.1.2.8 – White sap called latex flows from rubber trees when they are tapped.
Latex Rubber
Rubber is used to make many useful things. Some common items made of rubber are rubber boots, rubber tires, pencil erasers, disposable latex gloves, and latex paint.
The thick white sap of rubber trees is called latex. Latex is collected from rubber trees with a tap. Water is evaporated from the sap and either acid or sulfur is added to the latex to make it more flexible and stronger. The latex can be melted and molded into the desired products and it often is combined with synthetic rubber to add desired characteristics (for tires, for example). Although this latex is very useful to make various products, it is actually the method the tree uses to move moisture and nutrients from one part of the tree to another.
Rubber is used to make many useful things. Some common items made of rubber are rubber boots, rubber tires, pencil erasers, disposable latex gloves, and latex paint.
The thick white sap of rubber trees is called latex. Latex is collected from rubber trees with a tap. Water is evaporated from the sap and either acid or sulfur is added to the latex to make it more flexible and stronger. The latex can be melted and molded into the desired products and it often is combined with synthetic rubber to add desired characteristics (for tires, for example). Although this latex is very useful to make various products, it is actually the method the tree uses to move moisture and nutrients from one part of the tree to another.
Figure B.1.2.9 – Latex from rubber trees is dried and rolled into sheets.
Figure B.1.2.10 – Latex rubber is used to make many products, including tires.
Watch More
Dandelion Rubber
Rubber trees can be grown only in the tropics. Currently, scientists are researching how latex might be harvested from a special type of dandelion that grows in colder climates. (This is not the common dandelion appearing in your lawn, unfortunately!) Watch this video to learn more about dandelion latex.
Rubber trees can be grown only in the tropics. Currently, scientists are researching how latex might be harvested from a special type of dandelion that grows in colder climates. (This is not the common dandelion appearing in your lawn, unfortunately!) Watch this video to learn more about dandelion latex.
Maple Syrup
First Nations in Eastern Canada were the first to discover and collect maple syrup. They made holes in maple trees and collected the sap in birchbark containers. They heated stones in fires, then added the hot stones to the maple sap to evaporate water
from the sap and make the sap thicker. With enough evaporation, the sap becomes sweet maple syrup.
In late winter, maple tree sap starts to move water and nutrients to the top parts of the tree. This helps new leaves to start growing on the tree in spring. The sap can be collected from trees only in late February or early March. Warm days slightly above freezing start the sap flowing in the tree. Cold nights slightly below freezing stop the sap from flowing all the way to the high branches. This allows people to collect maple sap low on the tree trunk from a new hole each year. By the way, collection of sap does not harm the tree. The wound of the tap soon heals and the tree continues in good health -- something like a person donating blood!
In late winter, maple tree sap starts to move water and nutrients to the top parts of the tree. This helps new leaves to start growing on the tree in spring. The sap can be collected from trees only in late February or early March. Warm days slightly above freezing start the sap flowing in the tree. Cold nights slightly below freezing stop the sap from flowing all the way to the high branches. This allows people to collect maple sap low on the tree trunk from a new hole each year. By the way, collection of sap does not harm the tree. The wound of the tap soon heals and the tree continues in good health -- something like a person donating blood!
Figure B.1.2.11 – First Nations people have collected maple syrup for hundreds of years.
Figure B.1.2.12 – Maple sap drips from a hole in the maple tree trunk.
Figure B.1.2.13 – Maple syrup is a sweetener used in food.
Watch More
Making Maple Syrup
Watch this video to see how maple sap is tapped from trees and bottled into syrup using modern industrial methods.
Watch this video to see how maple sap is tapped from trees and bottled into syrup using modern industrial methods.
Canada makes the majority of the world's maple syrup. The art of making maple syrup is taken very seriously in Quebec.
Try It!
Capillary Action
This experiment will shows how capillary action works.
Materials:
This experiment will shows how capillary action works.
Materials:
- 3 clear cups
- water
- red food colouring
- blue food colouring
- spoon
- 2 paper towels
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cookie sheet or flat shallow pan with a lip
Instructions:
As you follow the instruction, you may want to look at this website to see some pictures of how to set up this experiment.
As you follow the instruction, you may want to look at this website to see some pictures of how to set up this experiment.
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Fill 1 cup half full with water. Add 3 drops of red food colouring and stir with a clean spoon.
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Fill 1 cup half full with water. Add 3 drops of blue food colouring and stir with a clean spoon.
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Place the 3 cups in a row on a cookie sheet or pan. Put the empty cup in the middle.
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Twist 1 sheet of paper towel into a sort of rope. Put one end of the twisted paper towel into the red food colouring cup. Put the other end into the middle empty cup.
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Repeat step 4, but use the blue food colouring cup and the middle empty cup.
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Wait 20 minutes and observe.
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Wait 1 hour and 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.
After 20 minutes, you should have observed coloured water travelling up both paper towels. After 1 hour, you should have seen the empty cup filling with red and blue water mixing to make purple-coloured water.
Water particles are attracted to each other, and they also are attracted to the paper towel. These attractions between water particles and the paper towel cause the water to “climb” the paper towels.
Water particles in plants are attracted to each other, and they are also attracted to the sides of little tubes in the roots and stems of the plant. These attractions cause water to move to all parts of a plant.
Try It!
Colourful Flowers
Try this experiment to produce colourful flowers. You will see how capillary action works in the stems of flowers.
Materials:
Try this experiment to produce colourful flowers. You will see how capillary action works in the stems of flowers.
Materials:
- 2 white flowers such as carnations or daisies
- 2 glass or plastic cups or jars
- sharp scissors
- knife
- water
- red food colouring
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blue food colouring
Safety Warning
Take care with scissors and sharp knives; don't cut yourself or anyone else!
Instructions (Part 1):
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Fill one cup half full with water. Add two drops of food colouring to the water.
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Using sharp scissors or a knife, cut the end from the stem of one flower, making the stem short enough to fit into the cup without tipping it.
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Place the flower stem in the coloured water.
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Leave the flower for 1 day. What do you observe?
Instructions (Part 2):
- Fill two cups with water. Add two drops of red food colouring to one cup of water. Add two drops of blue food colouring to the other cup.
- Using sharp scissors or a knife, cut the end from the stem of one flower, making the stem short enough to fit into the cup without tipping it.
- Beginning at the bottom of the stem, use the knife to slit the flower stem carefully in half. The slit should reach partway up the stem.
- Put one half of the stem in the red water. Put the other half of the stem in the blue water. Thus the one flower is standing in two cups of coloured water.
- Leave the flower for 1 day. 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.
The food colouring was dissolved in the water. The food colouring and water moved up the stem and into the flower petals through the process of capillary action.
Various tubes in the stem lead to various parts of the plant. The tubes in the red water stem bring water to half of the flower petals. The tubes in the blue water stem bring water to the other half of the flower petals.
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 2 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.
Trees evaporate water from their leaves through transpiration. Cutting trees means that less water goes into the air by transpiration. Less water in the air means that fewer clouds can form and the area will receive less rain. Therefore, cutting
trees in Brazil leads to a drier climate in Brazil.
In the middle of summer, the sap in the maple tree warms and it can move faster. The sap moves all the way to the leaves of the tree very quickly, so it does not drip from the lower trunk for syrup. In addition, its chemical composition has
changed -- and no tasty maple syrup will result from boiling!
Thick, waxy stems and leaves help water to stay in the plant. This is helpful in areas that receive very little rain.
Lots of water is lost through transpiration from plants with wide, flat leaves. Cacti grow in dry climates. Having thin spines that do not lose water instead of wide leaves that lose a lot of water means the cactus plant has a much smaller surface
from which it can lose water through transpiration. This keeps water inside the plant so it can survive with little rain. Also, spines add the benefit of discouraging animals from eating the cacti.
Over time, you would see the celery leaves turn a red colour as the water and food colouring move up the celery stem and into the leaves through capillary action.