Colour changing salt paintings

I saved the cooking liquid from our purple carrots (see previous blog) and thought it'd be fun to try a new colour-changing activity, themed around the fireworks that my boys were excited to see this week (mixed with a bit of fear, although the big one has been progressively more convinced that they are fun each day).  We've previously done Hungry Caterpillar-themed salt paintings, where I drew outlines with PVA glue and sprinkled table salt onto them.  When the glue dries, the salt absorbs any liquid that is touched to it, so it can be painted with food colouring or watercolours with the salt spreading the coloured liquid along the painted lines.

This time I added a little bicarbonate of soda to a teaspoon of salt, and separately added a little citric acid to another teaspoon of salt.  I drew patterns which were intended to look like different types of fireworks e.g. Catherine Wheels and fountains, and added the salt mixes and plain salt in different places, wobbled the paper to stick as much salt as possible to the glue then tipped the small amount of excess off.  I also wrote the boys' names on separate pieces of paper and did individual letters with different salt mixes.

Glue and salt ready to paint

I put a small pot of the purple carrot cooking liquid and a small paintbrush out for my eldest (4 years) to paint some fireworks.  He was very keen, and loved seeing the purple liquid change colour as he touched his brush to different areas of the salt.  I explained that I'd added a bit of acid and bicarb to the salt painting and it was the same colour change that he'd seen when we made our carrot rainbow.  As with the slices of carrot, the acid gave a more distinct colour change than the bicarb.

After doing his first firework picture (photos of this one), he moved onto his name, which he did very carefully, starting each letter in the place where he'd put his pen to draw them without me asking him to do it that way.  Whilst he was doing this, his little brother (almost 2) wanted a go, so I set him up with a similar pot and paintbrush and another of the salt paintings.  It's fair to say that he didn't get the idea of touching his brush to the salt, and wanted to paint the page like normal paper, which chipped the salt off!  His brother tried to explain, and although he exclaimed "pink" when he saw some appear, it was very definitely lost on him, and he upended the pot on the picture which did create a pretty effect but wasn't quite what was intended!

Colour changing Catherine Wheel

This was a nice twist on the salt painting we did before and it captured my 4 year old's imagination.  I might try something similar again - we could substitute red cabbage cooking liquid for purple carrot (as I don't often see the rainbow carrots for sale).  If you don't have citric acid, there are a number of sweets which contain sherbet that is predominantly citric acid and would likely work e.g. the ones that have a lolly you dip into sherbet or the 'flying saucer' ones.