Problem: Joanna Lumley and David McCallum played which pair in a TV series?
Answer: sapphire and steel

Problem: What is used in paper or textile making, and to form a protective coating on a canvas or other surface to be used for some art techniques?
Answer: size

Problem: Chatsworth House gardener, engineer and greenhouse expert, Joseph Paxton, created which iconic 1851 London building?
Answer: crystal palace

Problem: To within one year either way, in which year was Pluto discovered by Clyde Tombaugh?
Answer:
1930