An egg sits on a cardboard tube. The tube stands on a tray that rests on a glass of water. Strike the tray from the side, and the tray zips away. Does the egg drop into the water, or does it end up on the table? Find out how hard you need to hit — and why.
Inertia means an object keeps doing what it is doing unless a force changes it. That is Newton's First Law. The egg is at rest, so it tends to stay right where it is.
As the tray slides out, it rubs on the bottom of the tube. This rubbing force is friction. It drags the tube, and the egg on top, a little to the side. It is the only sideways force on the egg.
The tray's floor pushes up on the tube. That upward push is called the normal force. When the tray's back rim knocks the tube away, nothing is left to hold the egg up.
Now gravity is the only big force on the egg. It pulls the egg straight down. Any sideways speed the egg got from friction makes it drift as it falls.
A harder hit makes the tray move faster. The rim reaches the tube sooner, so friction has less time to drag the egg. If the tap is too gentle, friction speeds the tube up to match the tray. Then everything slides away together.
The egg falls about the same distance either way, so it hits at about the same speed. What matters is how long it takes to stop. A slower stop means a smaller force. Water gives the egg a slow, gentle stop.
Water lets the egg slow down over several centimeters. A longer stopping distance means a small stopping force.
A hard table stops the egg in about 1 mm. A very short stop means a huge force — more than the shell can take.
Bonus fact: water pushes up on the egg a little. This push is called buoyant force. A raw egg is a bit denser than water, so it still sinks — but slowly, and it settles gently on the bottom.