Making a sundial

When it was lovely and sunny a couple of weeks ago, we tried making a sundial. Hopefully it will be sunny again at some point so this might be something we can try again now we've found a way to do it that worked nicely! At least we still have the enthusiasm for finding out how full our rain gauge is for getting us through the rainy days at the moment...

As we were moving things around the garden during the day to keep everyone in the shade, I thought we should do something to look at how shadows move so we could talk about how the Earth spins. 

The first version involved using a big sheet of paper and the washing line (with a big pole). We put the paper around the pole and weighed it down with a brick. It's the sunniest part of the garden but doesn't get the earliest morning sun due to adjacent houses and trees, but we were able to put our first line on the paper to mark the shadow of the pole at 8:20am. We continued until it became overcast around 5pm, with some flurries of interest meaning some lines only half an hour apart, and others more widely spaced. The boy was initially interested and could clearly see the shadow of the pole had moved and liked reading the time on the real clock (with a little help). However, when drawing a line with a ruler proved too tricky, he wasn't keen to keep doing it so by the afternoon I was making a sundial by myself!  He also kept trying to spin the paper around the pole, which rather defeated the point (although it was parallel to the fence to start with so could be put back).

First attempt at a sundial

The second attempt was in a less sunny place, so we couldn't do it for the full day, but it had the advantage that we could draw with chalk and the boy found it a bit easier.  I also attempted to make it more clock-like by marking the lines every half hour and emphasising the hours. Every half hour, we stood a big felt tip pen in a pot the centre of the sundial (I needed something upright, but not too pointy, and the pen wouldn't stand up on its own). This worked nicely and I was looking forward to using it to tell the time the next afternoon, but sadly an overnight thunderstorm washed it away!

Afternoon sundial drawn with chalk

We had a look at his globe afterwards, and marked where we live with a blob of play dough. We took a torch to pretend to be the Sun, and spun the Earth around to watch the shadow move like the sundial. He quite liked it, although I'm not sure whether he fully understood as he's never tried to explain it to me again (which he usually does when he's excited about learning something new!). 

We'll hopefully get a chance to try this again before the summer is over (unless it is already?).