Questioning beyond textbook exercises and making an own (alternative) hypothesis to explain. Is it allowed in our education system?
|Hypothesis and Scientific Theory|
By this method, we are just stopping our kids to imagine or be creative.
So, let me go with the example, some very interesting questions that students asked in class.
1) Water and ghee, why does ghee floats in water?
According to the book, water is polar and ghee is nonpolar, so water repel out ghee and they get separated from each other. But why ghee floats in water? Water has the molecular weight of 18 g/mol, while ghee is a long chain hydrocarbon, its molecular weight is much larger than water.
Some of the hypothesis:
a) The density of ghee is less than water. But how? Check the molecular weight. Maybe spaces between hydrocarbon molecules are too large and water is too less because of hydrogen bonding.
b) Ghee floats in water due to buoyancy forces as a spoon of ghee can displace more amount of water than the weight of ghee.
But when a student asked this same question is school, the reply was "Itna pani main maat uchal" : Don't jump so much in water. Don't remember the exact dialogue what teacher replied, but the teacher didn't answer it and also discouraged the student from questioning.
2) In case of osmosis, where does water flows
Some of the hypothesis:
a) Water flows from region of higher solute concentration to the region of lower solute concentration because the region of higher solute concentration will be heavier as it contains the solute particle. (But when tested, the hypothesis is wrong. But the thing here is students are thinking, they are making their own logical hypothesis based on their previous experiences. Heavy objects push the lighter ones when kept one above other, so the student had thought this as explanation)
b) Water flows from region of higher concentration of water to region of lower concentration of water because of nature tendency to mix or entropy, but here another question arise:
3) Why there is nature tendency to mix? How will you explain it?
Maybe it's because of random pulling effect. When we add more water to a salt solution, the number of water molecules that pull the salt particles (ions) increases. So salt particles start getting distributed throughout the solution to form a homogenous mixture of lower concentration.
4) What will happen to the solubility if we add two solutes, e.g. sugar and salt in the water?
The book explains only about one solute, not about two. But if we add two solutes, the number of interactions increases i.e. interaction between sugar-water, salt-water, sugar-salt, salt-salt, water-water, sugar-sugar. The solubility of particular solute depends on strength of all these types of interaction now.
5) Why does freezing point decreases when we add a solute to the solvent?
As solute-solvent interaction is stronger than solute-solute and solvent-solvent in order to form a solution, some more energy is required to separate solute-solvent interactions. This reduces the freezing (melting) point.