On Friday 22nd September, the autumnal equinox day, we planned to do an experiment with some new friends in Spain. However, this day was very overcast in both countries, so that meant we had to postpone it until Monday, 25th. We both measured the length of the shadow cast by the sun on a vertical meter stick a number of times and at the same time in our school yards. We will be able to calculate an approximate radius of the earth once we link up with our friends in northern Spain. Here we are at work..