The team give the results of the world's biggest-ever brain training experiment, and reveal how viewers can make themselves smarter.
Jem tries to smash a land speed record with a fire extinguisher, a go kart and a well-oiled spanner.
Engineer Jem becomes a crash test dummy to discover how much g-force his body can take.
Dallas takes on lie detection technology and Liz looks at the dilemma that threatened to undermine Darwin.
Jem hits the furnace to make steel, while Liz investigates whether science can help humans live forever.
The team look at the science behind the volcanic ash crisis that has grounded Europe's planes, and Jem Stansfield finds out why steam is still powering the country.
Dallas hits the streets to find what makes people happy, and Liz travels to Norway to investigate the latest technology combatting climate change.
Jem straps a race horse to his car to explain what horsepower is, while Liz sets Dallas a free diving challenge that leaves him gasping for air.
Liz launches a huge experiment into the nation's sense of smell, and Dallas investigates evidence that the origins of life on earth might have begun in space.
