العلوم (بالإنجليزية) الصف الخامس الابتدائي، الأسبوع 2: Celery colours and body tubes

Light, roots and tubes

الأسبوع 2 · المحور الأول «الأنظمة»، الوحدة الأولى «العلاقات الغذائية بين الكائنات الحية»، المفهوم 1.1 «احتياجات النبات» (ب): الضوء وأجزاء النبات · 3 دروس

Celery colours and body tubes

Discovery Education Science P5: Term 1, Unit 1, pp. 24–31

GoalExplain what coloured water shows about a plant’s tubes and compare them with a person’s heart and blood vessels.

New words

circulatory system · the heart and blood vessels that carry blood round the bodyarteries · vessels that carry blood from the heart to the bodyveins · vessels that bring blood back to the heart

Explanation

If a stalk of celery or a white flower stands in water with food colouring overnight, the colour climbs up inside it. The coloured water has travelled up the xylem tubes. If a grown-up cuts across the stalk, we see coloured dots where the tubes are. A person also has a transport system. The heart pumps blood into the arteries, which carry it to every part of the body. The veins bring it back to the heart. Blood carries oxygen and nutrients such as glucose. Plants and people both move materials in tubes. The big difference is that people have a heart to pump, while plants do not.

	Plant	Person
Tubes	xylem and phloem	arteries and veins
Pump	none	the heart
Carries	water, minerals, sugar	blood with oxygen and nutrients

Worked examples

Hassan stands a white flower in blue water. By the next morning its petals have blue edges. The blue water travelled up the stem.

Rania puts two fingers on her wrist and feels a beat. That is blood pushed along an artery by her heart.

Karim counts 20 beats in 15 seconds. There are 4 lots of 15 seconds in a minute, so his pulse is 20 × 4 = 80 beats a minute.

Class activity

Coloured water test (a grown-up cuts and helps). The grown-up cuts about 2 cm off the bottom of a celery stalk with leaves, or of a white flower stem. Stand it in a cup of water with a few drops of food colouring. Draw it now and again after a few hours and next morning. Ask the grown-up to cut across the stalk so you can see the coloured dots. Nobody eats it. Then rest, sit quietly and count your pulse for 15 seconds, and multiply by 4.

Practice

Which plant tubes does the coloured water climb up?

Name the part of a person that pumps blood, and the vessels that carry blood away from it.

Nada counts 18 beats in 15 seconds. What is her pulse in one minute?

Write one way a plant’s tubes are like a person’s blood vessels, and one way they are different.