The Sunflower's Hydraulic Design

Most of us see sunflowers every day and enjoy, not only their beauty, but also the seeds which are good to eat for both humans and a variety of birds and mammals, and the stalks can be used for fibers for textiles. Sunflowers can reach 12 feet in height and have a head that is a foot or more in diameter. This head is not really one blossom, but actually a cluster of hundreds of small five pointed flowers.

What is interesting about growing sunflowers is the fact that they demonstrate phototropism, the ability to rotate their head so that the face of the head always faces the sun even though the angle of the sun's rays on the head constantly changes. That means that the head faces east as the sun rises, and follows the sun across the sky so that at sunset it is facing west.

Sunflowers along a picket fence Studies of sunflowers have shown that the way this is accomplished is by a hydraulic system built into the stem. Water accumulates on the shady side of the stem, and as the pressure builds it forces the head in a steady arc toward the direction of the light. Because it is a hydraulic system and a fluid is being used, the pressure is distributed uniformly on the back surface of the head, so it does no damage to the plant and yet provides enough force to move a large surface in a 180° arc. When you push on the brake pedal of your car, a similar system is used to stop the car.

Hydraulic systems are used in most mechanical objects that man uses where large amounts of force are needed--airplanes, trucks, bulldozers, etc. Engineers work carefully to make the systems work, and great intelligence is needed to design a system that will function without damage to the object being steered and yet provide enough force to accomplish the desired result. So, too, the sunflower has been designed to use a complex system to provide the movement of its large head toward the source of the energy that makes it work. The intelligence of God can be seen wonderfully in every part of the world around us, and the more we learn about how it works the more we see the wisdom and planning of God.

--John N. Clayton

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