Season 5

Jem makes his own diamond and then proves they aren't forever. Dr Yan explains the science of popcorn, and Dallas investigates why we haven't cured cancer yet, meeting the team that hope to change that.

In the second episode of the science series, Liz hits the beach with the RNLI to experience the power of rip currents; Dr Yan attempts to demonstrate evolution by drawing a couple of lines; and Jem is back in the workshop, turning everyday scrap into gold.

Jem Stansfield witnesses the power of rockets as he spends time with the team working on the Bloodhound land-speed record project. Dr Yan Wong re-creates an ancient Greek experiment to measure Earth's circumference with two sticks, and Dallas Campbell goes in search of a robot he can call his own.

Liz Bonnin investigates new stem-cell research that could change the face of organ transplant surgery, Dr Yan Wong tries out the Nocebo effect (placebo's evil twin), and at a memory boot camp Dallas Campbell discovers how to remember where he left his keys.

Liz investigates an increasingly common and unwelcome guest - the bedbug. Meanwhile, Yan explains why statistics are not to be trusted, and Dallas goes stargazing in California.

Dallas attempts to find out what causes tooth decay and gum disease. Yan explains the reason why refreezing food is not a good idea. Jem takes a look at some new research that claims electric lights can play havoc with the way we sleep.

Dallas investigates a potential global helium shortage, Dr Yan tests shoppers on how much they know about radiation, and Liz tries out the new airport security technology that can see beneath your clothes.

In the aftermath of the Fukushima radiation scare, the team turns its attention to nuclear power. Jem climbs into a reaction chamber to explain how a nuclear power station works and what happened in Japan. Meanwhile, Dallas investigates the clean-up operation for radioactive waste, and Liz looks at what radiation does to the human body.