Week 8 · Chapter 6 Transportation of Water in Plants: 6-1 Transpiration; 6-2 The Path of Water; Column: Blessings of the Nile · 3 lessons
3
Nile plants and cooler air
Science P6: Term 1, Chapter 6, pp. 54–61
GoalConnect plants along the Nile to the lotus, papyrus and cooler air.
New words
lotus · a water plant with wide floating leaves and beautiful flowerspapyrus · a tall plant that grows in water; ancient Egyptians used it for papercooling · taking heat away
Explanation
The Nile, Egypt’s river, is a home for many plants. The blue lotus is a water lily whose wide, flat leaves float on water and catch plenty of sunlight. Papyrus is a tall reed with a long triangular stem, and the straight tubes inside help carry water. Plants along the river, like palms, trees and crops, take in water and let it go by transpiration. When water changes from liquid to vapour, it takes heat from its surroundings, so the air near the plants becomes a little cooler. That is why sitting in the shade of trees near water feels fresher than standing on bare, dry ground. Plants help people in many ways: food, shade, fresh air and cooling.
Nile plant
What helps it
Blue lotus
wide leaves float and catch light
Papyrus
tall straight stems with water tubes
Palm and crop plants
roots reach water; transpiration cools
Worked examples
On a hot afternoon, Youssef sits under a palm tree near a canal. The air feels cooler than on the open road. The plants lose water vapour, and this takes some heat from the air.
The ancient Egyptians used the papyrus plant to make paper. Papyrus grows in marshy places where its roots can reach plenty of water.
Salma plants a small tree in the school yard with her class. They water it regularly. In a few years, the shade and the cooler air will help the whole yard.
Class activity
Shade check. With a grown-up, hold a thermometer in the shade of a tree and in a sunny, open place for a few minutes. Do not touch hot surfaces. Write both numbers and compare. Why is the shady place cooler? Trees also block sunlight.
Practice
1
Why do the lotus leaves float on the water?
They are wide and flat and light, so they float and catch sunlight.
2
What was the papyrus plant used for in ancient Egypt?
