成人快手

Childhood and teenage obesity is spreading across the world at an alarming rate 鈥� and this week the first evidence of the extent of the crisis has been published. Experts at the World Health Organization (WHO) and Imperial College, London analysed data from more than 2000 studies, involving 128 million children and adolescents worldwide. Claudia Hammond speaks to Dr Juana Willumsen from the WHO.

By measuring how carbon moves through Earth's ecosystems we can get a grip on how human activities are altering the carbon cycle. NASA鈥檚 Orbiting Carbon Observatory-2 (OCO-2) has been watching the Earth breathe from space since 2014 and the results show the impact of El Nino events, volcanic activity and forest fires and even the pollution from individual highways, as Deputy Project Scientist AnnMarie Eldering explains.

Incidental recordings of bird and insect calls before, during and after, the 2015 wildfires in Southeast Asia, reveals a clever way of assessing the damage caused by the haze from these fires to the biodiversity in Singapore. Caroline Steel reports.

The massive eruption in 1883 of the volcano Krakatau (Krakatoa) in Indonesia unleashed huge tsunamis. The explosion is thought to be the loudest sound ever heard in modern history, with reports of it being heard up to 3,000 miles (4,800 km) from its point of origin. So it may be surprising to hear that there are very few remnants of the pumice rock, spewed out in huge numbers at the time. One rare sample survived and is being analysed, along with samples of dust from the deck of the boat that was nearest the volcano at the time, in order to calculate just how explosive the eruption was.

A team at the Georgia Institute of Technology has built a record-breaking mechanical pump. The machine pumped molten tin at 1200 degrees Celsius continuously for 72 hours, and it has worked at even higher white hot temperatures. The pump is fabricated entirely from a heat-resistant ceramic material. Georgia Tech's Asegun Henry is developing the technology to transform the contribution that solar and wind energy generation can make in storing energy and supplying the electricity grid.

A new species of ichthyosaur - predatory marine reptiles that swam the world's oceans whilst dinosaurs walked the land - has been discovered. 成人快手 Science reporter Bobbie Lakhera explains, and we hear from palaeontologist Dean Lomax who made the discovery.

If you saw someone with a sign on the street saying 鈥渇ree listening here鈥�, would you pull up and chair, sit down and tell them all of your problems? In Oakland, California, passers-by are doing just that 鈥� thanks to the 鈥渁ctive listening鈥� of Sidewalk Talks volunteers. Those involved say it鈥檚 life-changing, as Alison van Diggelen reports.

The Science Hour was presented by Roland Pease with comments from 成人快手 Science reporter Bobbie Lakhera.

Producer: Katy Takatsuki

(Picture: Child at swimming pool. Credit: Getty Images)

Show less