Nina looks at different household inventions and finds out how they work. Russell, Kai and Ella ask: How does a key open a lock? Nina is on hand to unlock the answer. Show more
Discover 11,128,835 listings and 278,066 playable programmes from the BBC
Nina looks at different household inventions and finds out how they work. Russell, Kai and Ella ask: How does a key open a lock? Nina is on hand to unlock the answer. Show more