How do plants grow towards the light?

You've learnt about this in your science subject during secondary/high school.

It's interesting and I bet it still is. Why would the upshot of a tree grow towards the light and not elsewhere? Sciencefocus has a simple way of explaining it.

                          A weed in our unkempt flower vase

Plant cells contain a protein called phototropin that is mostly concentrated in the growing tip of the plant shoot. This protein unfolds into an activated state when it absorbs blue wavelengths of light.

This sets off a cascade of interactions between different proteins in the cells, which ultimately changes the alignment of cellular scaffolding proteins, called microtubules.

The upshot of this is that the cells on the darker side of the shoot elongate, while those on the light side remain squat and boxy. As the dark side of the plant grows longer, the shoot as a whole bends away from that side and towards the light.

Recent research at the Carnegie Institution at Stanford University, and Wageningen University in the Netherlands, found that the rearrangement of the microtubules can happen surprisingly quickly. Within minutes of exposure to blue light, plant cells will start making new microtubules.


Source: Sciencefocus

What is black box recorder made of?

The 'black box' of an aircraft is built to be virtually indestructible. But let's start by dispelling one myth about black boxes. Flight data recorders (FDR) as they are officially called, are not black, but coloured bright orange so that they an be found easily after an aviation accident.

Just like life buoys and life jackets.


The indestructible orange-painted box. Photo: Curtiss-Wright Controls


Aircrafts carry two black boxes. The flight data recorder continuously logs details like the plane's speed, altitude, time of day and engine parameters. The other unit records the pilots' voices in the cockpit.

The units are built to:-

• be resistant to fire and water
• be able to cope with the force of a major impact
• withstand low air pressures at altitude should the aircraft plunge into the ocean.

Because of this, black boxes require very strong casings. Earlier models were simply made from stainless steel, but now housings also incorporate titanium, as well as an inner layer of heat-resistant material.

Have a good weekend!


Source: Backpage of the SUNLife, January 26, 2014