Surfing has a dirty secret: surfboard production techniques are often at odds with the sport’s eco-conscious image. Most modern surfboards are a sandwich-like construction: a polyurethane foam core – known as a blank – coated in a fibre-reinforced composite.

Sharing emotions is a central part of human communication. Moreover, the internet is becoming an important medium to share them. And this has given rise to collective emotions in online groups.

A technology relying on holography, that involves measuring mechanical deformations, as signature of artworks has previously been developed to address the protection of cultural heritage.

The German village of Cappel is home to one of the greatest historical music instruments. The ornate baroque organ here is the work of Arp Schnitger, the grand master of German organ construction who built it in around 1680 for Hamburg.

Bill Wei is a senior conservation scientist at the Netherlands Institute for Cultural Heritage, in Amsterdam.