ONLY FOR GROUP 5

by Spain 1 group 5:

The paperclip is made with nitinol, and it's put in hot water during the experiment. Then, you heat it and because of that, the paperclip returns to its original shape.

Why?

The answer is in the disposition of the atoms of the metal.

Like in many alloys, the atoms of "shape memory alloys" like nitinol redistribute during the cooling. Unlike  normal alloys, the atomic bounds of the nytinol and other "shape memory alloys"  allow them to recover their original shape, when they return to heat.

That's why nitinol is called "shape memory material".

2nd revision : I don't understand aleations and SMA

3rd revision : OK !

N.Hoang (French science teacher)

Spain 1

(Pais Vasco)

by French group 5 :

On the surface of the water, the molecules (which ones?) are «tied», It's called the superficial tension. The pepper is hydrophobic , so it floated on the water with the superficial tension.You had put dishwashing liquid on your finger, and the dishwashing liquid had molecules with an hydrophobic body and an hydrophilic top. So these molecules are unstable in water, and they lower the superficial tension. So a lot of molecules of water are pushed away, and the pepper is taken by the current of the water, and it's why there is no pepper on the finger.

Good explanation. Correct your Englisk mistakes.

N.Hoang

by Spain 2 Group 3

This experiment can be explained through Bernoulli's Principle.

It states that as the speed of a moving fluid (liquid or gas) increases, the pressure within the fluid decreases.

That's right ... but, perhaps, you could add something about why the ball remains (or should remain :-) ) in air.

P. Sirabella