This problem offers you two ways to test reactions - use them to investigate your ideas about speeds of reaction.
Making a scale model of the solar system
Use your skill and knowledge to place various scientific lengths in order of size. Can you judge the length of objects with sizes ranging from 1 Angstrom to 1 million km with no wrong attempts?
How does the time of dawn and dusk vary? What about the Moon, how does that change from night to night? Is the Sun always the same? Gather data to help you explore these questions.
Design and test a paper helicopter. What is the best design?
Analyse these beautiful biological images and attempt to rank them in size order.
Can Jo make a gym bag for her trainers from the piece of fabric she has?