Chemistry Form One Notes – The Scientific Procedure

Full text version of Chemistry Form One Notes on The Scientific Procedure, transcribed from the supplied source document. Source images are intentionally omitted; all recognized text from the topic pages is included below.

Full text: This page contains the complete recognized text for source pages 46-55. For the original PDF layout and illustrations, use the WhatsApp button below.

‘The Concept of Scientific Procedure

Explain the concept of selene procedure

The scientific method (procedure) is a process that scientists use to ask questions and conduct

investigations to find answers to these problems. It is logical approach to prablem solving by observing

and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are

supported by data. The scientific method provides a standardized way for scientists to conduct thet work

However, many scientists work according o other methods as well,

‘THE IMPORTANCE OF THE SCIENTIFIC PROCEDURE

Explain the importance ofthe scenic procedure

Includes

1. The scientific procedure makes a researcher or an experimenter more systematic and organized

‘when investigating r solving a problem,

2. It gives a means by which one can get a solution to several questions about natural phenomnen,

why does water expand when it feezes?

3, Ttmay lead to discoveries and innovations

4 Provides background knowledge upon which Future references may be made

‘5. Itmakes our sense organs more effective in exploring ou natural world, That is, we Become more

sensitive to environmental changes

6. Itmakes us use the available resources mor sustainable in solving everyday problems.

7. Assists us in predicting the future outcome based on the present condition.

‘8 Assists us in testing the validity othe possibility of an event, phenomenon or problem,

“The main steps ofthe scientific procedure

Each Step ofthe Sciemific Procedure

Describe each sep ofthe scienfc procedure

Observation (identification) oF statement ofthe problem

‘The frst step ofthe scientific procedure isto identify a researchable problem. A problem isan obstacle

that makes it difficult to achieve a desired goal, objective or purpose. It refers toa situation, condition or

{issue that is unresolved. Observation refers to identification ofa chemical phenomenon, This may include

observing the colour, smell texture of a substance, and so on. Observing involves the use of Senses to

obtain information. Observation is more than the bare fat of observing. It is determined by use of five

senses namely, smell, touch, taste, vision and hearing. For example, o identify the colour of a substance

you have tose it with your eyes. The same case applies to detection of the smell ofa substance or gas

produced by reacting substances in laboratory. To beable to detect the smell of a gas you have to se

{your nose to smell it

(Observation helps a scientist to identify problem. Observation may involve making measurements and

collecting data The data may be descriptive (qualitative) or numerical (quantitative) in nature. Numerical

information such as the fact tha sample of sulphur powder measures 50g is quantitative. Non-mumerical

‘information, such asthe fact thatthe colour of anhydrous copper (ll) sulphate is white, i qualitative.

(Once you identify a problem, it becomes easy to state it scientifically, For example, you can observe that

‘when you puta given volume of water in a narrow container and expose it to open air, it takes much

Jonge to evaporate and decreas in volume, However, when you pu the same amount of water in a wide

container, it takes a much shorter time todo so. This phenomenon can be investigated scientifically

Hypothesis formulation

‘Afler identifying and stating the problem, you can formulate a testable hypothesis for that problem. A

hypothesis isa statement Ii a prediction or proposed solution toa problem based on prior knowledge or

own information about @ chemical phenomenon. It is a logical guess about the outcome of the

experiment. A hypothesis must be able to be tested, Therefore, a hypothesis ean be described a

tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further

lnvestigation. It can be rejected, modified, or accepted only after conducting an experiment to prove or

Aisprove it

Let us take an example of water atthe previous stage. It was observed that the water held in a wide

container evaporated faster than that ina nartow container. Based on what we know about evaporation

(prior knowledge) we can formulate a hypothesis pertaining to this phenomenon. Iis wll known that one

ofthe factors affecting the rate of evaporation isthe surface area, From this fact, we can formulate a

testable hypothesis which sates that “evaporation of water nereases with increase in surface area ofthe

comainer in which thar water is placed. This is just a statement. I can be proved wrong or correct by

Setting up and doing an experiment, Remember that this is just an example, though not very much related

to chemistry, We can turn to another relevant example as well

Now, let us look at an example of anhydrous copper (It) sulphate. The anhydrous salt isin powder form.

‘When you expose this salto open ai, it changes is colour and shape, fom is original white powder to

blue crystals, Why does this happen? From our knowledge of the properties ofthis salt (prior knowledge

‘or information gathered) when is placed in open a, it absorbs water vapour from the ar. Iis this water

‘vapour which it absorbs that tums it blue. We ean go as far as formulating a hypothesis, which states

that “When white anhydrous copper (I) sulphate power is exposed to open air, absorbs water vapour

rom the air and turns ino blue crystal”. We sll have a doubt about this hypothesis. How do we know

thatthe liquid absorbed by the sal is telly water? To accept or reject this hypothesis, we must conduct an

experiment

Experimentation

‘Afler making a hypothesis, the next step isto plan and conduct an experiment, Planning an experiment

involves writing down steps for an experiment that will answer the question. It should be remembered

that experimental plan should include short and clear steps It should also include the materials and

‘methods that will be used inthe experiment. These may include safety gers such as gogles, gumboos,

loves, ee, It must also state all expected hazards to be accompanied with the reacting substances or

chemical phenomena being experimented. This could either occu as a result of mishandling chemicals or

apparatus, improper experimental procedure or even testing the pret obained from the experiment

In the scientific method, an experiment is a set of observations (qualitative or quantitative) made in the

context of solving a particular problem or question. An experiment is conducted in order to retain of

falsify a hypothesis conceming a particular phenomenon, The experiment is a basis in the practical

approach to acquiring deeper knowledge about the chemical wold

Experimenting involves carrying out a procedure under controlled conditions in order to. make

observations and collet data To lear moe about mater, chemists stay systems. A system isa specific

Portion of matter in a given repion or space that has been selected for study during an experiment or

‘observation. When you observe a feation in a est tbe, the tes tube and is contents form a system.

4“

‘Your experiment es whether your hypothesis fie. ts important fr your experiment tobe &

fur test. You conduct fr test by mkng se hat you change only one factor ata ime while Keping

alee condions the same (constant). Tes ators at lo called variables. They arth factors that

affect the problem you want to investigate. They can change or be changed during the experiment. Sch

factors inl temperatue, volume, see, ight, cocenatin ight

¢ Ld

é Wy

ay *.

Snadntscondcting an experiment

There artes types of varibles These ae

+ Dependent variable: This sth fcr tat changes it value when the values ofthe ther

variables change. is the vale being measured

Independent variable: This isthe fitor tats manutd so so obtain diferent values

+ Controle (or constant) variable: Tis isthe fcr that docs ot change, oi kept constant alt

the time Ht oes not ae the res of the experiment

For example, you might be interested to camy out an experiment to determine the inlence ofthe

conection of phosphors fiir on maize growth To gst the rt esl, you grow maize in sila

conditions of sil and atmosphere envionment (conoid arable) but vary the quantity of eer in

cach et independent variable. Then you meas the eight of maize plans dependent alae afer

2 eri teal ftime a shown in igure blow. The vale ofthe eight you wil obtain wil obviously

depen on he amount concentration) ofthe eile appli This i typical txt. However, most

chemistry experiments do ot involve fret

[Now, lt us tum back to. our experiment Inthe example of determining whether the surfce area increases

the ate of evaporation or not, we ean design an experiment to prove or disprove tis phenomenon. This is

conducted by filing a basin (with large surface area) and a bucket (with small surface area) with 10 lites

of water cach. Then the two containers are placed in open air for 3 days. Here, care must be taken to place

both containers under similar environmental conditions. Containers must be of the same type, that is, both

rit be plastics, metals, ee. In addition, the water used must be obtained from the same source

= »

cre 50 phorphonsfriizer

1s 28% phosphons enlier

10% phosphors ferlzer

s 10

fetta

. sw mw 3

Time

The effec of frlizeron plant growth

“The only variable tobe kept constant isthe volume of water, which is sett the volume of 10 lites. You

should repeat your experiment several times to make sute thatthe first results were not jus an accident.

Determination ofthe effect of surface area on the rat of evaporation of water

Observation and collection of data

Observation and recording of data must be done from the beginning to the end of the experiment Data is

the information gathered during the experiment. This can include descriptive (qualitative) and numerical

(quantitative) data. Numerical data is that which can be measured, for example, 10 lies of water, Sg of|

copper, a five centimetre long ribbon of magnesium, ec. Qualitative data include information that cannot

bbe measured, eg colour, shape or appearance, smell, fel, etc. Recording data is an important part ofthe

Scientific method because it helps sciemists organize thet ideas and observations. Chants, graphs, lists

diagrams, tables and even sketches ate all the ways of recording data during experiments, Records

appearing in the form of tables are easy to read, understand and interpret

Continuing with our hypothetical experiment for determining the effect of surface area onthe rate of|

evaporation, we expet that at the end ofthe experiment the volume of water in each container will have

Aropped to a certain extent

We also expect that the volume of water lost fom the basin willbe bigger than that los rom the bucket.

‘This means that more water will evaporate ftom the basin than from the bucket. Considering that

scenario, we can then predict what the data can be lke. Let ws take this model asa real experiment and

assume the kindof results that could be observed and collected during the experiment.

‘Afler 3 days of the experiment, water from each container was measured. The results obtained were

summarized in the following table

Source: hypothetical

ata collected from evaporation experiment afer 3 days

Amount of water Type ofcomainer

Basin Bucket

Initial volume Final volume 10 tres 70 lies 10 liees 85 lies

Amount of water lost,

(evaporated off) 30lites 1S lies

ata analysis and interpretation

(Once your experiment is complete and after you have collected data, you analyse your data tose if your

hypothesis is truco fs. In table 41, we find that, atthe end ofthe experiment, 3 lites of water had

evaporated off from the basin as compared to 1 ites from the Bucket. What does this data tll us? What

{sitrying to reveal? This means that from the basin with large surface area) water evaporated faster than

that from the bucket (with small surface area). The data reveals the fact that surface area plays @ major

role in evaporation of water and many other liquid substances

However, you may sometimes get unexpected results. You may find tht your hypothesis was false. In

such a cas, you will construct a new hypothesis and start the entire process ofthe scientific method over

‘gain. Even if you find that your hypothesis was true, you may want to test agin ina new way.

Conctuson

“The lst tage (at this level of study) ofthe scientific method isto make inferences and draw a conclusion.

Scientists look at the information they gathered and observed. Then they make connections to draw a

comelusion, These conclusions may’be or may not bein agreement with their predictions, Scientists make

incorect predictions all the time. An important part of the scientifie process is to understand why

predictions were incorrect. Many scientists will repeat an experiment Several times to see if they ean

replicate the results before concluding. This ensures that they have conducted the experimen the same

way each time and make sure no introduced errors or ouside Factors affected the experiments outcome,

[Based on data ina hypothetical experiment above, we found that 30 lites of water evaporated fom the

basin (a container with wide mouth and hence a large surface area). At the same time, 1 lites of water

evaporated from a bucket (a container with a narrow mouth and hence a small surface area). From this

result, of course, we can conelude that evaporation of water increases with increase i surface area ofthe

comainer in which thar water is kept. Therefore, our hypothesis is proved true and corect. Remember

always to base your conclusion on the collected and analysed data, though it may deviate, to some extent,

fom the reality for one reason or another.

ADDITIONAL NOTES ON SCIENTIFIC PROCEDURE,

Inadvanced study, the last step ofthe Scientific method is to share what you have learned, Scientists share

information so that others can use the findings to create diferent questions and conduct different

experiments, Sharing information is an important part of working together. Profesional scientists will

publish thei final reports in scientific joumals, magazines, books, or even present their results at

Scientific conferences. For the purpose of study at this evel, the lst stp is conclusion,

[Even though we show the scientific procedure asa series of stps, keep in mind that new information or

thinking might cause a scientist to back up and repeat steps at any point during the process. A process ike

the scientific method tat involves such backing up and repeating is called an iterative process. Therefore,

the siemifi process isan iterative process

Applicaton ofthe scent procedure

“The scientific procedure is used in many areas and in different Fields of study. It is especially applied by

Scientists and researchers to find solutions {0 various scientific problems. Below are some ofthe areas

where the scientific procedure is applied

1 Im scientific researeh: Researchers normally apply the scientific method when conducting,

researches on diverse scientific problems or phenomena. A researchable problem whose solution

is sought for without following the correct sequence ofthe steps ofthe scientific method is not

Tike to get resolved,

2 Ima field study: A field stay (or field work) i offen conducted to find answers to problems or

{est hypotheses. I involves doing some practical work that applies the scientific methods

3. When conducting experiments: An experiment is « methodical procedure carried out withthe

goal of verifying, falsitfing, o establishing the aeuracy of a hypothesis. Experiments vary

greatly in their goals and scale, but always rely on repeatable procedure and logical analysis of

the results

4. Im project work: A project is a planned piece of work that involves careful sty ofa subject or

problem over a period of time, so as to find information onthe subject or problem,

The Scientific Procedure to Carry Out Investigations in Chemistry

Use the Scienifi procedure to cary out investigations in chemistry

In this chaper, we have used two major examples to explain the concept of experimental procedure in

etl. These are the rate of evaporation of water and exposure of anhydrous copper(I) sulphate powder

to open air. Fr casy understanding and quick reference by students the two examples are summarized

below. Note thatthe test for the anhydrous copper(I) sulphate powder was not explained in full

However, the summary can give you a good picture on how to go about experimenting it

A. The rate of evaporation of water

Steps

1 Problem/question: Does surface area affect the rate of evaporation of water?

2. Hypothesis: Evaporation of water inreases with increases insure atea

3. Experimentation: A basin and a bucket ate filled with 10 lites of water each. They are left

expose to open air, under similar conditions for a period of 3 days

4. Observation and data collection: Aer 3 days, the remaining water in containers was measured

‘carefully. The results were recorded in table,

5. Date analysis and imterprettion: was found tht 3 lives of water had evaporated frm the

‘asin and 1S lites ffom the bucket From this dat, it was discovered that much water (3 ites)

hhad evaporated from a container with large surface area (basin) as compared to only 1S lites of

‘water that had evaporated ffom a container with a small surface area (bucket).

6 Conclusion: Since a large amount of water evaporated from the basin as compared to that from

the bucket, it is coroct to conclude that surface aca affects the rate of evaporation of water and

‘thatthe larger the surice area the higher i the evaporation, Therefore, the hypothesis i proved

tobe me

‘. Exposure of anhydrous copper (If) sulphate powder to open air

Steps

1. Problem/quesion: Why does anhydrous copper(I) sulphate powder change into hydrated blue

xystals when exposed to open ai?

2. Hypothesis: When exposed to open at, the anhydrous copper (I) sulphate powder absorbs water

‘vapour fom hear and this water vapour turns it to blue erystals

3. Experimentation: The anhydrous sulphate is exposed to open air to absorb sufficient water

‘vapour Then the hydrated sulphates heated to dive out al he Liquid in it

4. Observation and data collection: The sample of hydrated blue crystals loses the igidin it and

turns 10 its orginal white powder. The vapour given off s carefully collected, cooled down to

Tiguid, and then putin a beaker or est tbe

5, Data analysis and imerpretaion: The collected liquid is subjected to various water tests to justify

‘whether it is water or just the other liquid substance. The liquid i denied as water

{6 Conclusion: The anhydrous copper (It) sulphate was exposed to air only. We also know tht sit

contains water vapour. Because ofthis reason, iis correct to conclude that the water came from

the water vapour contained in ar. The water ted the white powder to be crystals. Therefore,

‘our hypothesis is tr,

GET ORIGINAL PDF NOTES THROUGH 255620339260