Using a famous optical illusion, McCann Milan has come with an ingenious ad for non-profit organization Exodus Fondazione. Titled ‘Reverse Test’, the 45-second film shows a miniature road sign behind an empty glass into which water is being poured. As the water level rises, the arrow on the road sign changes direction from right to left. Check it out below.

How it works

A physics concept called refraction, the bending of light, causes the arrow to change direction when viewed from behind the glass. Physics Central explains: “Light travels from the air, through the glass, the water, the back of the glass and through the air again, before hitting the arrow. Every time it passes from one medium to another, it refracts.” Here’s a graphic that explains the phenomenon.

A similar experiment that uses refraction

We at DS tried the experiment and can confirm it does indeed work. Very clever campaign by McCann Milan. Seen a better ad in this genre recently? Share this post and voice your views in the comments below. Check out more such creative public service ads from all over the globe.



