Will it float, or not float?

Task notes

• The contestants are seated side-by-side on the stage island, with their backs to the audience.
• Each contestant is holding a green auction paddle with the word ‘Float’ printed on it, and a red paddled with the words ‘Not float’ on it.
• Greg and Alex are stood on the stage, with Greg standing behind a semi-transparent plastic baby bathtub containing water, which is elevated on a platform on a box with wheels.
• Inside the box, there are 10 items which Greg shows to the contestants before they have to predict whether it will float or not in the water. The items are as follows:
  1. A small cactus in a pot
  2. A (fake) milkshake with (real) whipped cream and a cherry on top
  3. A (very dense) rubber duck
  4. A lime
  5. An orange
  6. A (regular) rubber duck
  7. A recorder
  8. A house brick
  9. An egg (fresh)
  10. Another egg (also fresh)