Four real life scientific investigations

You want examples? Here they are:

Animal studies:

1. Test whether dogs react more to smell or to their owner's attention to an object: they have to choose between a plate that smells more of food and a plate their owner paid attention to

2. Test whether dogs can follow their owner's gaze: owners call the dogs and then look somewhere and we see whether dogs follow this gaze (look up gaze-following, it's important for learning!)

3.  Test whether birds can use tools: give bird a long stick and a box with a peanut inside and see if they can use the stick to get the peanut out

4. Test whether vision can develop in the absence of stimulus: bind kitten's eyes at birth and see if they'll develop perfect vision (they didn't...)

18 mm wide. It is the product of the width and the number of eggs.