Take 3 banks: two half-liter and one liter. One jar, fill with clean water and immerse the raw egg. It will sink.
The second jar pour a strong solution of salt (2 tablespoons to 0, 5 liters of water). Lower back the second egg - it will float. This is because salt water is heavier, and therefore easier to swim in the sea than in the river.
Now put on the bottom of the egg liter cans. Gradually pouring the water in turn from both the small cans, one can obtain a solution in which the egg will neither float nor sink. It will be held as suspended in the middle of the solution.
When the experience carried out, we can show focus. Pouring salt water, you ensure that the egg will float. Pouring fresh water - that the egg will sink. Externally, salt and fresh water is not different from each other, and it will look amazing.