Sun - Day Three

Today was a busy day of ferrying Tom back and forth and visiting the library for a very special reason (see The Parkers Abroad) but we managed to fit a couple of activities in between.

We wrote messages in invisible ink and revealed them with heat, another Science Kids activity.  The invisible ink we used was lemon juice, the sort that comes in a plastic lemon that lives permanently in the fridge, we wrote on copier paper with cotton buds then left it to dry.

The words should be revealed when the lemon juice oxidizes as it heats up so for that you need a heat source, we tried several

• The sun, which revealed a bit but wasn't hot enough
• The instructions on the site said a light bulb but that didn't work either
• The iron on maximum heat with guess what, no luck
• A candle, this just about got the lettering showing and almost set the house on fire

this one says 'hecky peck said Nana'

Jacob and I had a talk about why it didn't work, we came to the conclusion that light bulbs in New Zealand (where the Science Kids is published I think) are very hot and you shouldn't skimp on made-from-concentrate lemon juice and squeeze a fresh one.

We also started a sundial on the patio, it is a work in progress because of all the running about we did today, hopefully we'll finish it on Friday if it doesn't rain first.