When I was investigating mirages a couple of months ago I came across an idea to make your own and it’s been on my list to try. We did it today and it worked really well – easy for kids to do and fascinating. Definitely one to try out with preschoolers and up, the toddler enjoyed putting it together but couldn’t actually see it. Or that could be because she was an exhausted grumpy bum.
Anyway. What you are doing is creating two clear layers in a glass, they bend the light in the same way layers in the atmosphere do and create a mirage if you are looking through them. You need a fairly large glass, a jug, spoon, salt and water.
Boil some water and dissolve as much salt as you can in it. Hot water will dissolve quicker and easier than cold water, but then you need to let it cool completely before you can use it. The salty water is more dense than fresh water and will sit on the bottom to make a layer, but hot water is less dense than cold water. So hot salty water and cold fresh water mix more easily and don’t give you crisp layers.
Pour the cooled salty water into your large glass.
Carefully pour fresh water on top of the salty water. I used a spoon touching the top of the water and poured onto the spoon, the water then ran off onto the top and made a second layer. This worked so well we could actually see the sharp boundary between the layers (although unfortunately it wouldn’t photograph). If you hold a glass and look up through the side, you can see a reflection at the surface. We could see that type of reflection between our two layers and a distinct, sharp line around the glass, as sharp as an oil/water boundary.
Look at something through the glass and you will see a mirage as light is bent differently in the two layers, as shown at the top. If you are using a round glass your image will also be stretched sideways. We used a glass with lots of straight sides and the image was fine but there were lots of them – the girls found that just as fascinating as the vertical distortions.
You can even get ambitious and have multiple layers by varying the amount of salt you dissolve, I got a three layer mirage working when I was testing it. And of course you don’t have to put a simple picture behind it – do it with photos of your kids. Definitely try this one, it was simple and fun.
Enjoy this article? Subscribe to the weekly newsletter to hear about them all. Or grab my RSS feed