My daughter (aged ten) and I make and set up a sundial. We learn the importance of weather and annoyance of shade, try different ways of making them and ponder what effect changing seasons will have. A few weeks later we use the knowledge to work out which way the wind is blowing.
236 – Sundials
Saturday 10 May. Sunny! 22°C
“Can we make sundials?”
That was about six weeks ago. B always has the best ideas – it hadn’t occurred to me at all. I was very excited but it took us quite a while to actually do it. It felt a bit complicated, and it was, but not in the way I expected. I was worried they’d be really complicated to make. I had in my mind those ornate ones you find in country houses sometimes and I couldn’t get my head around it. B wasn’t thinking of that though and when, about five weeks on, we started thinking about it properly I found this site which was very helpful.
It took us about five minutes to make them. I took a plant pot to the beach when we were exploring tides and rockpools and filled it with shingle. At home I added some stones to the top and then found a stick and stuck it in. The website suggested working out your latitude and sticking it in at a corresponding angle… I guessed.
B had something else in her mind though and makes a simple cardboard one with a sheet of cardboard underneath and a rectangular bit sticking up in the middle.
I’m confused. “Doesn’t it need a long pointy bit?”
She’s confused too. “Why?”
I try and answer about shadows and sun and working out the time but I’m not sure enough of my ground. In the end we keep an open mind and then work out where to put them.
Here we hit an obstacle. A bit like the unhelpful need for totally sunny days (so rare in South Wales) we are clearly going to also need a site where there is sun throughout the day. Our house typically has sun on one side in the mornig and the other in the afternoon. After discarding the public outside spaces near us as impractical for obvious reasons, we decide we’re going to have to go up on the flat garage roof. We get the ladder out ready.
We’re aiming to get out and up for 7am on Saturday morning. We make it at 9. We negotiate the ladder carefully and arrive on the roof with two sundials, stones, a compass, and some pens. Then we work out how to place them.
I try and position the plant pot sticky one so that the stick is pointing due north. It’s in at a big of an angle to reflect being in the northern hemisphere (I’m not pretending it’s exactly measured – very much rule of thumb). We then copy that with B’s cardboard rectangle one – so that it’s sideways to the north.
Both provide marvellous shadows straightaway. The stick sundial creates a clear long line. B puts a stone in the middle of the line and writes ‘9’ on it and we write it on the roof underneath too for luck. Only later do we realise we should probably have put it at the END of the shadow line. Ah well.
The cardboard sundial is surprisingly satisfying. It creates a long shadow and we mark where it comes on the cardboard base and put 9 by that too.
At ten o’clock we go back up. The pointy sundial has clearly moved round to a new point.. and the shadow is a bit shorter. The cardboard shadow is shorter too. We go back up at 11 and find a similar change. At 12 we go up wondering if it will be exciting.
The cardboard one really is. The shadow on that is almost non existent and it’s clearly about to flip to be on the other side. B is smug. The pointy sundial shadow line is a lot shorter (though still a foot or so long) but isn’t quite directly under the stick… I reckon I’m about twenty minutes out but as we’re quite west for BST time I’ll take that.
B is excited. We talk about BST time and she’s really impressed with how both sundials have worked. Back up in the afternoon and we can clearly see the range on both now. I’m kicking myself for not realising the length of the stick and the stick’s shadow was important. We debate whether to go up last at 7pm or 8pm. We opt for 7pm and it’s a good move. The stick shadow is almost to the edge of the roof and the cardboard one is way over where the edge of the card is. At 8pm we look down on it from the back bedroom and the shadow of neighbouring buildings have put the whole roof in shadow.
We leave the pointy sundial up there with its sharpie markings and stones. We’ll go back up in a few months time and see if anything’s changed. I suspect the stones won’t last that long but we should be able to tell if the sundials numbers are still in the same place.
221 – Working out which way the wind is blowing
Sunday 25 May. Windy 16°C
A few weeks on from making the sundial we’re dog walking on a very windy day. We start trying to work out which way the wind is blowing.
B: “We don’t have a compass”
Me: “We should be able to work it out without one. Where’s the sun? What time is it?”
Helpfully its 12.10pm… not the best time to work out where east or west is but we persevere. B points at the shadows and thinks East must be the opposite way. I’m not sure. We dig out the map on the phone and I’m right.
Me: “No, that’s south”.
We’re confused by this and then realise it must be because the sun is further north because it’s almost mid summer. Or because it’s not directly overhead at noon. We watch the shadows. Ten minutes later they even out and seem like the sun is exactly over head. We feel proud of ourselves, remembering how the sundial wasn’t centred at 12noon but at somewhere between 12 and 1pm.
We’re more confident on east and west now and try and work out the wind. We get to the open area on top of the cliff and the bend of the trees clearly demonstrates that it’s coming from the west and going east… we’re not sure if this means it’s an east wind or a west wind so we resort to the phone again. WEST. We both feel we learned something.
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