Tuesday 13 October 2009

A Victorian Masterpiece


Today a group of us visited Newcastle's Swing Bridge, built in the 1870s by Sir W G Armstrong & Co. The gleaming machinery should give you an idea of what a lovely piece of working heritage it is.

With the help of some very big hydraulics, the bridge can rotate (swing) to enable ships to pass. As I suppose you might expect from engineering that originated from an arms manufacturer, the wheeled mechanism on which it rotates is basically built on the same principle as a giant gun turret.
All the children were given the chance to press the button that works a (really loud!) hooter that alerts people on either side of the Tyne that the bridge will be turning. We were really lucky because our visit was on a day when a swing was planned. So we climbed to the viewing tower (scarily steep steps!) and watched as engineer, George, put the engines into action. It was amazing to see the gap open up between the shore and the edge of the bridge:



And it was stunning to see these old engines in action and to marvel at how quietly they run. A real Victorian masterpiece among all the iconic bridges over the Tyne.

Friday 9 October 2009

Hydroponics

Here are a few photos of our experiments with hydroponics. Apparently, most supermarket lettuces are now grown hydroponically, which I guess explains how little soil you see on the leaves. We sowed some fast-growing cress seeds in expanded hydrogel. In the petri dishes, we experimented with one watered only with water and another with some vinegar added
.
In the cut-down bottles we tested seeds fed with some nutrients (the packet of blue-tinged powder) against a control of watered seeds.
The seeds in the 'vinegar' dish didn't germinate at all; the seeds in the shallow, watered dish did germinate but didn't really grow much - possibly too shallow a layer of gel or insufficient water?
Both the deeper containers allowed germination and growth. But the best shoots were, surprisingly, those that weren't fed the nutrients.

We'll keep observing the two deeper containers to see what happens over the next few days. We may need to investigate what happened to prevent the nutrients from working. I've read on some forums that some proprietary nutrient formulae act like junk food on hydroponically grown plants, so maybe we've supersized the portions too much and left them bloated and unable to function.