Glowing in the dark

As the nights are drawing in and it's getting dark before the children's bedtime, I thought it was time to try out some more activities that work well in the dark. I thought my 3 year old would like things that glow in the dark (phosphorescence, where they absorb light and then emit it later), so I bought a couple of inexpensive glow in the dark things to play with.

The first was some glow in the dark letter stickers. I fancied another way to engage the small boy in spelling that isn't his beloved Alphablocks and thought some glow in the dark phonics might be fun!  I suspect they have a bit of strontium aluminate (which I think is activated by europium) in them, as they glow green in the dark after they have been illuminated with white light and stay glowing for a long time. As I wanted to be able to move the letters around, use them multiple times and not make them too edible for the baby (who eats everything), I laminated them and cut out sizeable circles containing the letters.  These work fine - they survived the heat of the laminator and absorb light through the clear plastic.

I also bought a small (10x10cm) piece of a material called Lumaglow as it sounded like fun. You shine light on this and then it fluoresces, and you can erase your picture with more light then use it again.  This material also has green phosphorescence which is really bright, but loses its fluorescence notably over a period of a couple of minutes, hence the ability to erase pictures using more light and then draw again.  Their website doesn't explain the technology behind this fully, but I wonder if it's zinc sulphide based (with a copper activator) as this doesn't glow for as long as the letter stickers... 

It's getting close to Halloween and the small boy is quite keen on his pumpkin collection (we have four, one for each member of the family, which is another story as I'd intended to just have one, but so far the small boy has adorned his with electric play dough) so I went for a pumpkin theme to our play. I set up the word 'pumpkin' with the glow in the dark letters (conveniently this works phonetically) and cut out some orange cardboard as a Jack-o'-lantern pumpkin. I got him to read the word (in his excitement he ran off to show Daddy the letter 'p' before attempting to read it!) and then to put the cardboard pumpkin on the Lumaglow and shine a torch on it. When he removed the cardboard, there was a shadow of a pumpkin! 

Glow in the dark letters spelling 'pumpkin' above the pumpkin shadow

He was quite excited about the pumpkin and this was also taken to be shown to Daddy. We had more of a play with the Lumaglow and did several more pumpkin shadows, some handprints (after initial reluctance, I'm not sure what he thought was going to happen to his hand!) and some dinosaur shadows. He also experimented with making pictures with the LED torch as you can see dots for each LED and after he accidentally left a glow in the dark letter on the material when he shone the torch, we discovered that you can use them to leave shadows and made the word 'pumpkin' as well as 'pin', 'ink', 'pump' and 'pink'.

Shadow of the word 'pumpkin'

I like the Lumaglow, it's quick to use and there are lots of different things you can do with it. I imagine if you had a bigger piece you could be more creative but the sample piece was an inexpensive purchase whereas the larger pieces are a bit pricey unless we really get into playing with it. I'm sure we will revisit this very soon given the dark evenings.  When the initial excitement of discovering glow in the dark materials passes I'm sure we will do some more spelling and I will attempt to explain in simple terms about phosphorescence.

Glow in the dark art