Oct 3

Oct 3 Easy invisible ink

There’s a very special magic that happens when science and art combine.

When I was an arty teen at high school I felt sure these areas were poles apart (cue the teenage eye-roll!), but of course the reality is that they work together all the time. Creativity relies on scientific thinking, and vice versa… think engineering, architecture, even cooking.

Here’s a very simple and fun activity your kids will love. It’s easy, spectacular, and delights with a wonderful grand finale that relies on a scientific principle: that some substances change colour when in contact with an alkaline.

Best of all, this colourful and creative science/art fusion requires only small quantities of a few simple ingredients that you’ll probably already have in your kitchen.

You’ll need:

a sheet of white paper
water
bicarbonate of soda
ground turmeric
hand sanitiser
a paintbrush
a small container to mix

Make a paste by adding water to the bicarb.

Step 1: the paste

Mix a runny paste by slowly adding water into a teaspoon of bicarb soda in a container, and combine them with a spoon or paintbrush. If you’d like to use this activity as a finger-painting or hand-printing opportunity you can mix the paste directly onto a plate.

Use the paintbrush or fingers to paint, splot, splash, dash or dab the bicarb paste onto a sheet of white paper. As it’s white on white it may be tricky to see what you are painting, but trust the process and have fun.

Let it dry for 10 minutes or so, and rinse out the container as you wait.

Paint the paste directly onto the paper.

Step 2: the paint

Put a dollop of hand sanitiser into the clean container and add a sprinkle of turmeric, then mix with the paintbrush to combine. Sanitisers tend to vary in viscosity so you’ll have to use some judgement here, and be aware that the turmeric can stain.

Just a sprinkle of turmeric onto the hand sanitiser will be enough.

Step 3: the fun

Use the paintbrush to paint the turmeric paint over the page. The areas painted with the paste will turn bright rust-red against a bright yellow background. It’s magic!

Note… this will be a piece of ephemeral art rather than a keeper… as they dry the colours fade, and the pasty areas may crumble. But that’s a learning opportunity in itself.