Anaglyph for 3D video

Anaglyph is the technical name for a technique of making images that have a stereoscopic 3D effect - so rather than appearing flat like a picture they appear to have depth like objects in the real world.

The anaglyph technique uses glasses with coloured filters to make it so that each eye sees a slightly different view. You can read up on how they work and how to make them yourself on Wikipedia. It's actually quite easy with modern technology, but the technique is quite an old one.

There are applications outside entertainment, and anaglyphs can be used help visualisation in science and design. Examples include viewing microscope images and models of chemicals. You can see some anaglyph photographs in the 3D gallery on the firrs webpage.

This video is mainly a bit of fun, but it shows how the anaglyph technique can be used in moving images. You can watch a much higher quality version here.

Forestry, timber and climate change

Forests and climate change are very closely linked, but in ways that are not generally well understood by the public. The science is complex and interconnected and often you hear only one side of the story. Fortunately the Forestry Commission has recently released a video that covers the subject in a very clear and balanced way. It also tackles a few widely believed myths too. I challenge you to watch it and see if it doesn't tell you something that surprises you.

The reality is that human impact on forests is both a problem and a solution - and that we need science to tell us what the consequences of our actions are. If you are thinking of a science or engineering based career that helps save the planet you couldn't do much better than working in the forestry and timber.

Forests are vast sinks of the greenhouse gas CO2 but they offer so much more - from renewable energy to low carbon building materials...just so long as they are sustainably managed. The challenge for foresters is to use science to understand both the effect of forestry on climate change ...and the effect of climate change on forestry.

You can download a high quality copy of the video at the Forestry Commission's website: http://www.forestry.gov.uk/forestry/INFD-6umkar

Virtual forest tour

UPM's Forest Life is a really beautiful combination of Flash, still photography, video and audio. It takes you on a tour of a Finnish forest looking at trees, plants, animals and people. Find out about how forests are managed sustainably for different purposes and how there is much more to a forest than just the trees.

The science of sound

Here we have a couple more films from the Prelinger Archive. The first from 1933 and the second made in 1948...back when a scrap of wood on a piece of string was carried by every child.

These videos explain the science of sound...what it is and how it's made. This will help you understand our video "measuring stiffness with sound".

National tree week

"National tree week" starts today and runs until the 2nd of December. The Tree Council has organised several events around the UK celebrating trees and planting new ones.

If you want to know how to identify some of the trees that grow in the UK from their leaves you can play Kerf's leaf quiz on the main firrs website. There are more identification guides over at the Woodland Trust's Nature Detectives.

Tree planting is a great team building and feelgood activity to do in schools...and it goes on all over the world. This is a video made by a school in Costa Rica.



Trees can be planted as seeds, as small saplings, or as young trees several metres tall. Remember, although larger trees give instant satisfaction they also weigh more. It's also good to have a bit of expert advice to make sure the trees thrive and you know how to look after them.

You can still join in even if you don't have much outdoor space ....you can plant a tree as a bonsai.

Deforestation and certification

This video from Greenpeace has a forceful message. It asks the question:

"Why destroy ancient forests for wood and paper, when it can all come from responsibly logged timber?"

Why indeed.

Well one reason this happens is that many people don't really understand how they can choose wood products that are environmentally sustainable - and come from properly managed forests. There is good wood and bad wood and we all need to understand the difference. Check out the certification schemes like FSC and look for the logos. Buying certified wood is a good thing...it encourages people to look after their forests.

Measuring stiffness with sound

It is very useful to know the engineering properties of the timber in logs before they are sent to the sawmill. Time and energy spent sawing up a log and kiln drying the battens is wasted if that timber later fails to meet the grade for construction. It would be much better to put that log to another use.

The science of sound allows us to do just that. The speed of sound through any material is related to the material's stiffness. In fact, stiffness equals density times the speed of sound squared.

That means if we can measure the speed of sound and the density we can calculate stiffness.

To do this we measure how long it takes the sound to travel from one end of the piece of timber to the other. Then it’s simply a case of speed equals distance divided by time. To explore the science further why not look at our whack-a-stick simulation or read about our exhibit at the Royal Society Summer Science Fair 2007?



This was one of the first videos we made. Annie and Heraa had just started their Nuffield Science Bursaries and we were practicing using the video camera. It just so happened that on the day, Peter Carter from Fibregen was visiting the laboratory to talk about his acoustic testing tool with John and Andy from the SIRT project.

We decided it was a good opportunity to make a short video, so Annie and Heraa asked Peter how it worked and we videoed Annie doing a demonstration.

This tool, the HM200, is called the Director, but people also call it the "Hitman". It is designed to work in busy, noisy timber yards but in the quiet of your own home or classroom you can make your own "non-destructive acoustic testing device". All you need is a microphone and a computer with some software that will analyse the frequency of sound. We have found that the free software called Audacity can do this well enough for a demonstration.

When you hit the end of the wooden batten with a hammer, the main sound you can hear is the sound of the first mode of resonance. The frequency of the first mode of resonance is the time it takes the sound to travel along the batten, bounce off the end and travel back down the length of the batten. This means the wavelength of the first mode of resonance is twice the length of the batten.

It sounds complicated at first, but it’s actually quite simple. All you need to do is hit the piece of timber and analyse the sound to find out what frequency it was mainly made off. So long as everything is working as it should, that is your first mode frequency.

To calculate the speed of sound in the timber:

(Speed of sound) = (wavelength) x (frequency) = 2 x (batten length) x (frequency)

And to calculate stiffness:

(Stiffness) = (density) x (speed of sound) x (speed of sound)

Here is some proof that we did not fake anything for the video. We took the audio recorded from the video and opened it in Audacity (we've extracted the sound of the hammer strikes so you can do this yourself). We then selected the sound of the hammer strike and selected "plot spectrum" from the "analyze" menu.

What we want to look at is the frequency spectrum – that's the graph with frequency on the horizontal axis and the level on the vertical axis. The higher the level the more of that frequency there is in the sound.

The sound contains lots of different frequencies, but we are mainly interested in the highest peak. This is a frequency of 554 Hz.

And if we look at what the figure on the laptop in the video it says 558 Hz. Pretty close huh?



Did you notice the time on the laptop clock? We don't work that late! That was New Zealand time. The laptop was Peter's and that's where he lives.

The story of a forest ranger

This is another film from the excellent Prelinger Archive. This one was made in 1954 and looks at the job of the forest ranger in the USA. Again, you might recognise parts we used for our own videos.

Notice how the forests are talked about as a resource...but also how emphasis is placed on sustainable forestry and protection of the environment...even back in the 50s! Notice also how they stress the importance of avoiding forest fires. Back then many people smoked and lots of fires were started accidentally. Forest fires are still a big issue...all over the world (the UK included).

Wood for war - wood for peace

Ironically, the fact that we now have so many well managed forests in the UK is down, in part, to two of the most destructive events of the 20th Century: the two world wars.

During the First World War (1914 to 1918) Britain had great difficulty meeting the demands on timber - particularly for coal production and trench warfare. Britain's forests had been on the decline since medieval times and had been put under enormous pressure by the industrial revolution. Timber had been imported in large quantities for hundreds of years, but the war meant this supply was no longer reliable.

In 1919 the Forestry Commission was created and charged with reforesting the country with the help of private foresters. The idea was to improve the productivity of the forests and to create a large reserve of wood that could be called on in times of emergency.

Such a time came only a couple of decades later with the Second World War (1939-1945). During the war, the Commission's forests produced nearly one and a half million cubic meters of wood and nearly ten times more came from private estates.

These were times of great social change too. The 'lumberjills' were the forestry equivalent of the land army girls, but they weren't just felling trees - they were planting too...and the forests have been growing in size ever since.

Over the last 40 years or so the Forestry Commission has included conservation, ecology, recreation and tourism within it's objectives...and that's why we have today's multipurpose forests.

This is a video from the Prelinger Archive that was made during the Second World War looking at the same things from the American perspective. You might recognise parts we used in our videos.

Lolly stick bridges

We found loads of videos on the web of people's lolly stick bridge competions - from highschool science classes to engineering students at university...and in every single one people were having a lot of fun!

Now you could do this with lolly sticks (or popsicle sticks as the americans call them), modelling matches (the ones without heads), balsa wood, or with the wooden coffee stirrers you get in fancy coffee shops - you can buy a box of those quite cheaply. For fixings you could use glue, sticky tape, drawing pins, or even string.

Standing on the bridges looks a little bit risky - not least because everyone gets to know how much you weigh. Instead you could be more scientific and hang a bucket of weights off the bridge. The figures in this video are in pounds. There are 2.2 pounds in a kilogram.

There are lots of other things you can do instead of bridges...how about cranes, towers, roofs or even fighting walls. You can even make a lolly stick bridge using no fixings at all - just lolly sticks and nothing else! Maybe one day we'll show you how...

Launch of the firrs DVD

In October we will be launching the "firrs DVD" - over two hours worth of videos about the science and technology of wood and the people involved ...plus a whole load more cool stuff.

If you live in Scotland you qualify for a free copy, which we can post to you if you let us know where you live.

We will be launching the new DVD at the Forest Education Initiative and Forest Schools Networking Event in Pitlochry on the 4th and 5th of October.