Day 1

Sunlight

We circle around this life-giving Sun
Whose centre defies measure of temp. or ton
Simple atoms squeezed into new forms pure
Energy released more and more
It makes its way to surface bright
And on Earth transforms what is day from night
A race and a dance across the void
Of electric and magnetic effect
From distant star we measure their age
And on cold mornings turn our face for warmth
To sunlight made in past times forgot
Turning the wheel of evolution's lot
Clouds, weather, temperate zone
A fly, a snow peak and a bee buzzing moans
Complex shapes and straight white lines
Our colourful illumer from ancient times.

I was to work with Ellen on this programme to try and make distilled water to top up the car battery. I really wanted to make a parabolic solar furnace so we got cracking. I had hoped to make a full size dish but as a first try we made a simpler version which is rather like a cross section of a dish.

Today was hard work. The first day of the filming session is often hard because the crew have to get so much footage to establish the programme. So we spend a lot of time having to set up shots and it feels very slow to move on. Also one is at one's most anxious because you need to get so far to know what to do next and to know how well things are going. Also there was a lot of manual labour needed to get all the holes drilled and all the team: Sandra, Ellen, Steve and I, were drilling at the same time! Also, a very hot day indeed.

David got me to do this amazing jammy shot. We need broken mirrors for this challenge and so he asked Derek to set up a camera near to a mirror and positioned so that my reflection can be seen. He then asks me to juggle with three rocks for a bit, talk about how we need some broken mirrors and then hurl one of the rocks into the mirror. The shot was great first time, hit the mirror right in the middle and it shatters into tiny pieces. I made a one in a million perfect shot at the mirror - which disintegrates.

Start to make the mount of the mirror. This is an equatorial mount which, if it is set up correctly, will allow us to track the sun over the day with just the movement of one control.

Mirror shape takes longer to build than I had thought, partly because there were bans on sawing so that other filming could be done nearby. Ellen makes the supports for the mirror shape, Sandra drills holes in the base, Steve and I carve out the mounting holes in the mount. Mike L shows us how to use a brace and bit which cuts the drilling time down by 100th!

Very dehydrated today, never needed a shower so much. I drank soft drinks and water all night 'til going to bed but still ended up waking up dehydrated in the night.

Day 2

Awake to rain! This is as bad as no wind was for the windmill in the first series of Rough Science! But I guess it will pass.

Start the day with a funny scene trying (struggling) to get the mount out of the door of the factory and into its resting place for the solar furnace. Talk about how it works, the pole star etc.

Ellen and I finish cutting the mirror supports down and start to fix them to the base. Fix the thin plywood onto the supports to form the parabolic surface. Ellen and I start to fix a mosaic of mirrors onto the surface with drawing pins. Try out the mirror on flat ground roughly pointing to the sun (midday by then). Not as hot as I would have thought, a little disappointing.

Our flat mirrors are focusing the light into pencils of light rather than spots and so I guess it does not feel so hot. Should be OK for heating a largish kettle though. Added the kettle to the focus of the mirror which lights up wonderfully. I don't think it will be hot enough to boil water but it will heat it too hot to hold.

Set up the mirrors on the mount and Ellen starts to cement the mirrors in place. Mount seems to position the mirror OK and just about stands the weight when it is at an odd angle because the Sun's elevation is low. First test runs with a kettle full of seawater producing some condensation on the plastic tube. There is a slight possibility that the water collecting in the collection glass is due to water falling down the spout from above! But the water in the slightly dirty kettle is murky brown while the collected water is clear. Unfortunately, Derek, Ellen and I each take it in turns to accidentally kick over the collected distilled water with our feet!

Ellen and I do a piece to camera where we go through the maths of the parabola and how this formula gives us the numbers to make the basic structure to put the mirrors on. It took a long time to do because we needed to get the chat as brief and as clear as possible. I think this part is very important as maths is the language of so much science. Nice for us to be able to get this across.

Take the mirror off the mount to take indoors to protect it overnight.

Day 3

First job today was to put fixing wires into the metal support wire that holds the kettle. This is so that as the mirror tilts when we move it to track the sun, the assembly stays rigid and central. Otherwise the weight of the kettle tends to make it fall around.

Re-assemble the mirror onto the mount so that we can get as much sun time as possible. Today we stop at 3pm because Kathy's light bulb has to be filmed from a boat and we all have to go off and be filmed on location - so we don't have much time. Also the clouds are rolling and so it does not look a great day for solar collecting!

By about 10 am we have set up everything and we leave it in position until the sun gets a little higher in the sky (otherwise the mirror is at a silly angle - too low). The sun is already too hot for me. I've really struggled with the heat and the sunlight these last five days or so. Even by 10am I am feeling strange - we really need some shade. Ellen and I make up a simple palm shade. She said she was surprised at the way I was doing it as she would have done it completely differently! I guess we both use what is to hand but in our own way - that makes sense.

We make up a sunshade out of three palms and a wooden support, carry it out to the solar furnace and Ellen fixes it up with rocks to support it. However, the TV crew wanted to film us doing it and so we took it down and they filmed us walking along and trying to put it back up. I say trying to put it back because we could never get the rock to fix it up again and every time we put it up and sat beneath it, it fell down on us - much to the amusement of David, Derek and John!

By 11-ish we had collected no visible amount of water so I tried playing around with painting the bottom of the kettle with black paint. I was also worrying about the seal on the kettle lid not being tight and losing a lot of steam. When you opened up the kettle you could see condensation on the lid but very little coming down the plastic tube. So I played around with replacing the kettle with a glass flask and bung with some seawater inside and collecting from this. However the weather was on the turn and I think our sunshine was over for the best part of the remainder of the day.

The rain pours and pours so I collect rain water!! I collect over half a litre by having loads of jam jars and lids collecting the drops, even from the guttering!

I put back the kettle because I realised there would not be time to test the other device out and also because it would have been too much filming to include the new developments with no obvious benefit in the time available. Also, it would have been fun to try and make a full mirror either by fixing two such mirrors to form a cross, or better still by making a real 3D surface based on the same formula. This would have been quite big but if we had time I know that this would have worked really well. But there you are - the real Rough Science Challenge is the TIME challenge.

Kate, Ellen and I do the handing over of the distilled water. I filled the glass jar with a guess at what we had made from yesterday (we spilt it three times!!) but also we talked about how you could use the rain water a few times for the battery and the salts and chemicals picked up as it fell from the clouds would only be a problem after repeated usage. Also, it's OK in this rainy season but the solar furnace would have come into its own in the dry season when there is no rain for months.

At about 3pm we go to the dive centre in the town and after an hour waiting for the sun to go down a little (we needed to film the sunset or dusk and so there was no point being out on a boat and waiting around in the midday heat) and to have the necessary safety talks. We finally head out on the boats to Sandy Island which is a coral reef that formed a sand bank and island after one tropical storm a few years ago. There are even trees growing on it now.

We stop the boat in about 4 or 5 feet of water above some coral. This is Kathy and Mike B's big challenge to drop the light overboard and use it to light up a part of the coral. The bulb has to last long enough and also must remain airtight as water entering the bulb would have ruined it.

We filmed the exciting sequence three times because after each time the light was a little more amazing and so the editors could choose the best. It was so good to be out in the boat and exciting too. The view back as we went back to shore was wonderful, the setting sun lighting up Sandy Island in silhouette and the whole thing framed by incredible bubbly red clouds above the sharp horizon of the Caribbean sea. A really great memory to have! I would really love to paint that scene.

Content last updated: 27/07/2006