The Longitude Prize offers a £10 million prize pot to help find the solution to one of the greatest issues of our age. Votes from the British public will decide what that issue will be. This week, the six shortlisted challenges have been unveiled. They cover flight, food, antibiotics, paralysis, water and dementia. Alice Roberts talks to Adam about why we need an X-factor for science. Over the next month, Inside Science will profile each of these challenges and explain how you can cast your vote.

Matter from Light

In 12 months' time, researchers say they will be able to make matter from light. Three physicists were sitting in a tiny office at Imperial College London and while drinking coffee they found what they call a fairly simple way to prove a theory first suggested by scientists 80 years ago: to convert photons - i.e. particles of light - into electrons (particles of matter) and positrons (antimatter). Adam discusses the work with theoretical physicist Professor Steven Rose from Imperial College London and science writer Philip Ball.

Longitude challenge - Dementia

How can we help people with dementia to live independently for longer? Dr Kevin Fong is the champion for this Longitude Challenge, arguing that we all use technology to support our lifestyles but that people with dementia need extra tech. Marnie Chesterton visits Designability, a Bath-based design charity that works with people with dementia to develop new technologies. Their Day Clock shows that a simple design can produce radical results.

Coastal deposition

The destructive winter storms that hit the UK caused were flooded by the worst tidal surge on the east coast in 60 years.

Sand dunes play an important defensive role on our coastline but little is known about their resilience or recovery rate. So after the December 5th storm, scientists sprang into action in Lincolnshire with a new project that officially began in February. The aim is to help future coastal management by researching the effects of storm surges on sand dunes.

Producer: Fiona Roberts.