The most tangible way to comprehend science concepts is ‘learning by doing’.
It has been very well said by Confucius –
I hear and I forget. I see and I remember. I do and I understand.
The pragmatic approach for learning science rudiments is by conducting experiments, starting from simpler Hands-on to Lab. experiments.
So, the Motto of science learning becomes –
“Experimentation, Experimentation and Experimentation“.
Experiments are a part and parcel of science learning. Many so-called difficult concepts can be subdivided into simpler rules, derived from previous knowledge, observations and logic. Then, based on previous knowledge/ observations, a chain of experiments can be developed to arrive at the BIG, FINAL Concept/ Rule.
Experiments are hands-on activities every child enjoys and performs with great delight and interest.Even the weakest child feels enthused and motivated when he experiments with his own hands. Here, he uses his own intellect and creativity and sees things happening in the way written in the text books. Such a hands-on activity has an indelible mark on his cognition.
Science concepts which are dependent on a number of factors or conditions can be easily taught and explained by CONTROLLED EXPERIMENTS technique.
In Controlled Experiments, all conditions are kept CONSTANT except for the one which you want to test/ verify.
The ADVANTAGE of a Controlled Experiment is that you can eliminate much of the Uncertainty about your Results.If you couldn’t control each factor, you might end up with a confusing outcome.
Learning Controlled Experiment Method With An Example
We want to find out which conditions are required for seed germination.
We know from our previous knowledge/ observations that when we sow a seed in the soil, we give it the following things or conditions:-
Now we need to devise an experiment in which we keep controlling one condition at a time which we want to verify, and keep all the other conditions Constant.
Let’s verify each condition one by one–
BOWL 1: We control the factor ‘soil’ by eliminating it and germinating seeds on moist cotton(to provide water). Other conditions ie. air, water and warmth are kept constant.
BOWL 2 : We control the factor ‘water’ by germinating seeds on dry cotton (to eliminate water). Other conditions ie. air and warmth are kept constant.
BOWL 3 : We control the factor ‘air’ by keeping the cotton containing seeds immersed in water (to cut off the air supply). Other conditions ie. water and warmth are kept constant.
BOWL 4 : We control the factor ‘warmth’ by putting the seeds on moist cotton in a refrigerator.So, other conditions ie.air and water are kept constant.
After a few days we observe the following results :-
BOWL 1 : Seedlings develop; so soil is not necessary for seed germination.
BOWL 2 : No seedlings develop; so ‘water’ is an essential requirement for seed germination.
BOWL 3 : No seedlings develop; so ‘air’ is an essential requirement for seed germination.
BOWL 4 : No seedlings develop; so ‘warmth’ is an essential requirement for seed germination.
Conclusion- Since no seedings develop in Bowl -2, 3 & 4, so we infer that water, air and warmth are the three essential factors/conditions for Seed Germination.
Extrapolation – Since seedlings develop in Bowl 1, we infer that soil is not required for seed germination. This means that seeds can germinate without soil also.This is because, in the initial stages of growth/germination, the embryo utilises the food/ nourishment stored in seed cotyledons/ endosperms to give rise to the baby root (radicle) and the baby shoot (plumule).By the time, the first few leaves appear, the food stored in the cotyledons/endosperms gets exhausted and now the leaves make food for the plant. Also, by this time the seedlings should have been planted in the soil for further growth.
Some examples of science concepts which can be better understood by Controlled Experiment technique
1) ‘Buoyancy’ which depends on factors like volume of the object and density of the liquid
2) ‘Evaporation’ which depends on factors like surface area and temperature
3) ‘Photosynthesis’ which depends on factors like presence or absence of chlorophyll, carbon dioxide, and sunlight
4) ‘Rate of a chemical reaction ‘ which depends on factors like amount of reactants, temperature, presence or absence of catalyst
Ponder a while and get going …it’s simple & fun!
STAGE 4 SEED GERMINATION (HOME GROWN) IMAGE
Home grown Pinto bean seeds (on moist cotton in a bowl ) showing Stage 4 of Seed Germination. It shows Developing Seedling with coming out of First leaves and Epicotyl leaving Dried Cotyledons below........(.images for Stages 1, 2 & 3 also available immediately )