EN हिं

NCERT Solutions for Class 5th The World Around Us Chapter 6 Why roots hold a tree up — Activity 1

Book page 96 Updated on2026-09-19

Q1.
Take a rectangular piece of newspaper or used paper, and roll it into a thin tube. Glue the edges so it does not open. Then, make it stand it up on a flat surface. Does it stay up?
Answer

No. The plain paper tube does not stay up. It wobbles and falls over almost at once.

What to do, step by step.

  1. Take one rectangular sheet of old newspaper.
  2. Start at one long edge and roll it up tightly into a thin tube, about as thick as your thumb.
  3. Put a line of glue along the loose edge and press it down. Wait a minute for it to dry, so the tube does not open again.
  4. Stand the tube up on the desk, on one end.
  5. Take your hand away slowly and watch.

What you will see. The moment you let go, the tube leans a little to one side and falls flat. Even if you get it to balance for a second, one puff of air or one shake of the desk knocks it down.

Why it falls: The bottom of the tube touches the desk in only a tiny circle. A tall thing standing on a tiny spot is easy to tip. As soon as it leans even a little, its weight is no longer over that tiny circle, and it keeps going — down. This is exactly what would happen to a tall tree with only a thin stem and no spreading roots.
Try it fairly: Do not press the tube into a groove or lean it on a book. Stand it free on a flat, level surface. That is the point of the test.
Q2.
Now, cut 3 – 4 small triangles from thick paper. Stick the triangles evenly around the bottom of the roll. Rest the paper on a flat surface again. Does it stay upright now?
Answer

Yes. With three or four triangles stuck round the bottom, the tube stands up on its own and does not fall.

What to do, step by step.

  1. Cut 3 or 4 triangles from thick paper or card. Each one should be about the size of your thumb.
  2. Fold a small flap along one side of each triangle. The flap is what you will glue.
  3. Stick the first triangle to the bottom of the tube so that it stands out sideways, like a small foot.
  4. Stick the others on at equal distances all round the tube — not all on one side. Three triangles go at about a third of the way round each.
  5. Let the glue dry. Then stand the tube on the desk and let go.
  6. Now blow on it gently, and give the desk a small tap. It still stands.
Plain tube — falls Tube with a base — stands touches in one small spot weight spread over a wide base
Left: a bare paper tube tips over. Right: four paper triangles give it a wide base, and it stands — the same trick a tree's spreading roots use.
What you triedDoes it stay up?Why
Plain paper tubeNoIt touches the desk in a tiny circle, so a small lean tips it over
Tube with 3–4 triangles round the bottomYesThe triangles make a wide base. Now the tube must lean much further before it tips
Triangles all stuck on one side onlyNoIt is held on one side only, so it falls the other way
Tube with a coin taped inside the bottomBetter, but still wobblyExtra weight low down helps a little; a wide base helps much more
Why it happens: Anything standing up stays up only while its weight presses down inside the patch of ground it is touching. A thin tube touches a tiny patch, so it tips at once. The triangles make that patch big, so the tube can lean quite a lot and still not fall. That is exactly what the huge buttress roots in the picture on page 95 do for a rainforest tree — they flare out from the bottom of the trunk and spread the tree's weight over a wide circle of soft, shallow soil.
Look for the same idea around you: a table fan with a heavy round base, the three legs of a camera stand, the wide feet of an electric pole, the flared bottom of a tall flower vase. Nature thought of it first — nature often has the best designs.
Was this helpful?