Straight's A's: Science

SCIENCE - FORM 1

INTRODUCTION TO SCIENCE

SCIENCE IS PART OF EVERYDAY LIFE

1.Today we can travel very far within a short time by jet planes. we can communicate with people overseas through the telephone and by e-mail. we can cure many diseases and transplant organs from person to person. This progress has been made possible by science and scientists.
2. Science is the study of natural phenomena.
Examples
(a) Science studies what happens in our surroundings and why they happen.
(b) Science studies the growth of a human being from the time it is formed in the mother's
womb until it is an adult.
(c) Science studies why a ball falls to the ground.
3. A scientist uses his knowledge on science to solve problems, to discover and invent new things help mankind.
4. Science is always expanding because we have and inquisitive mind which is always asking
questions and trying to find answers to them.
5. However, science has limits and cannot answer all questions or solve all problems. For example, scientists cannot cure all diseases and cannot prevent volcanic eruptions or earthquakes.

1. Natural phenomena are incidents that take place on their own in our natural surroundings.
2. Natural phenomena take place all the time involving living things and non-living things.
3. Examples of natural phenomena include:
a) earthquakes
b) volcanic eruptions
c) monsoons
d) eclipses of the moon and the sun
e) formation of rainbow
f) formation of seeds and fruits
g) freezing of water and melting of ice
h) germination of seeds
j) birth of babies and their growth
i) turtles returning to the shore a lay eggs.
4. Scientists get a lot of knowledge by studying these natural phenomena.
5. As a result of their work, we are now able to understand and control some of these phenomena for our benefit.
6. For example, we are able to invent machines for predicting earthquakes, we are able to understand and cure many diseases and we are able to control rivers and use their water to produce electricity.

Science has made great contributions towards mankind. As a result we are able to live more comfortably and longer.
1. Science help us to solve problems.
Science has helped us to supply water to our paddy fields by irrigation. We are able to control plant pests and so produce more food.
2. Science help us to make things quickly.
With the help of machines invented by scientists, we are able to make things very quickly in large quantities.
3. Science helps us to make our work easier.
Machines make our work easier. A tractor can plough a large paddy field in a short time. This saves us a lot of time and work.
4. Science helps us to enjoy our leisure.
The television and the computer games have made our leisure more enjoyable. The motorcar enables us to take our family members for joy rides whenever we are free.
5. Science makes communications easy.
Information can now be relayed through telephones, computers, discs and satellites.
6. Science help us to maintain good health.
With the discovery of more drugs we are now able to live healthily. Advance in surgery has even made the transfer of organs from person to person possible. We can expect to live much longer than our forefathers.
Science involves the study o many things. It can be divided into many branches so that each branch deals with the study of particular things an offers different careers.

1. Science is very important to us. Through science we get to know and understand the enviroment and ourselves.
2. Science is a way of thinking that can bring answers to the problems we face.
3. Science enables us to develop new technologies
4. Technology is the application of science knowledge for our needs. Technology can helps us in our daily lives and improve our standard of living.

YOUR SCIENCE LABORATORY

1. The laboratory is a place equipped with apparatus for conducting experiments, investigations and tests.
2. Accidents can occur any time in a laboratory and students must follow laboratory safety rules.
3. Here are some laboratory safety rules that students must follow while working in a laboratory.

1. There are many hazardous substances in the science laboratory.
2. Below are some common hazard warning symbols that warn of dangerous in the laboratory

Hazard warning symbols on chemical substances in the laboratory.

1. Laboratory apparatus is used when doing scientific investigation.
2. Here are some common apparatus used in the laboratory.

3. Other common apparatus that can be found in the laboratory are shown below.

1. A Bunsen is used to heat things in a laboratory.
2. The air-hole allows the intake of air when burning.
3. The collar is used to open or close the air-hole.
4. When the air-hole is closed, the flame is yellow in colour and is called a luminous
flame.
5. When the air-hole is open, the flame is blue in colour and is called a non-luminous flame.
6. The comparison between a luminous flame and non-luminous flame is shown below.

1. Temperature is the degree of hotness or coldness.
2. The temperature of an object tells us how hot or cold an object is.
3. A hot object has a high temperature while a cold ocject has a low temperature.
4. Temperature is measured in units of degree Celsius (^oC).
5. Temperature is measured with a thermometer.

1. The laboratory thermometer consists of a long glass tube with a bulb at one end as shown in the diagram below.

The laboratory thermometer
2. The bulb contains mercury, a silvery liquid metal.
3. The glass tube is marked in degree Celsius from -10 to 110.
4. When the thermometer is put into a hot liquid, the mercury expands and rises up the tube
to show an increase in temperature.
5. When the thermometer is put on ice, the mercury contracts and falls to show a drop in
tempurature.

STEP IN A SCIENTIFIC INVESTIGATION

The desire to understand arises from what happens in our sorroundings. Questions like the following may be asked.
a) Why do frogs live in water and on land?
b) Why do coconut trees grow in sandy areas?

1. A hypothesis is a proposal of thought (idea or prediction). Hypotheses are possible explanations for the phenomena that we observe.

2. A hypothesis that is accepted after going through experiments can become a theory and if
the hypothesis is rejected a new hypothesis has to be formed.
Example:
- A problem is:
Why do iron nails left out in the open rust quickly?

-Hypothesis formed:
Water is necessary for iron to rust.

3. Observe whether a hypothesis can be tested. If it cannot be tested then it cannot be
formed as a hypothesis.

1. An investigation is planned after a hypothesis has been formed. While planning an
experiment, it is necessary for you to follow some guidelines.

2. At the beginning, you need to list the material and apparatus required to carry out the
experiment and the way the material and apparatus are to be set up.

3. Besides this, you need to know the way to collect, analyse and interpret data. Determine if
a table or a graph is required.

1. Variables are situations or factors that can change in an investigation. Examples of
variables are time, mass, temperature and the amount of substances used.

2. In a scientific investigation one variable is manipulated to study its relationship with a
responding variable (dependent variable). At the same time, other variables are kept
constant.

3. Three types of variables are shown below.
a) A variable that is kept constant
This variable is kept constant or fixed in a scientific investigation.

b) A variable that is manipulated
This variable is used to test a hypothesis.

c) A variable that responds
A change in this variable is determined by the variable that is manipulated. This variable is the result of data collected from the investigation carried out when testing a hypothesis.

Example

Hypothesis: Water is necessary for the rusting of iron nails.

Experiment to determine whether water is necessary for the rusting of iron nails

An experiment is carried out as shown in figure above. The apparatus was left for three days. The results obtained are shown in the table below:

In the above experiment,
a) the variable that are kept constant are the type of iron nail, size of the test tube and the
surrounding temperature.
b) the variable that is manipulated is the presence of water.
c) the variable that responds is the rusting of the iron nail.

The experiment is carried out to test the hypothesis by changing the variable that is manipulated. The results of the experiment showed that the iron nail rusted in th presence of water. Therefore, the hypothesis can be accepted.

When you are carrying out the investigation, the following steps have to be followed.

Collecting data

a) When you are collecting data all the observations or measurements have to be recorded
honestly and accurately.
b) Data that are collected can include the quantity of chemicals, length of an object, time
taken, etc.

Analysing and interpreting (evaluating) data

a) Data collected from and experiment are changed to figures that can be entered into a table
or chart in graphic from for analysing data.
b) Data can be interpreted in the form of a table or graph . This step is substantied with a
statement to show what took place during the investigation and then finding a meaning for what has been observed.

Making conclusions

1. An accurate statement describing the problem identified is made.
2. The acceptance or then rejection of the hypothesis.

A report is made after carrying out a scientific investigation based on a certain format. An example of the format is shown below.

The following are examples of simple methods of scientific investigations.

Example 1:

Eksperiment 1

The experiment below is carried to study the relationship between the length of the pendulum and the time taken for the simple pendulum to swing.

Physical Quantity And Their Units.

1. Measurement is important and is often used in science.

2. In science we need to measure length, mass, time, temperature and electric current. These
quantities are known as physical quantities.

3. Table below shows physical quantities and the International System of Units (S.I). The S.I. unit a system is used by all scientists in the world.

Physical quantities and the S.I. unit for each measurement.

4. The physical quantities that are used in specification and labels of goods have certain values and units.

Example:

1. Prefixes used in measurements include mega, koli, centi, milli and micro.

2. Symbols for prefixes are signs that state or identify each prefix.

3. Values in science are usually written in standard form, i.e., using a number to the power of 10. The aim of writing a value in standard form is to make it easier to record the readings that are very big or very small.

4. The value of a physical quantity can be written using the standard form with a prefix.

Example 1.

Change the value of physical quantities below to the standard form, and to prefix form.

Use Of Measuring Tools

1. Length is the distance between two points.
2. Length is usually measured in units of kolimetres (km), metres (m), centimetres (cm) and millimetres (mm).

3. Different tools are used to measure different types of lengths.

Using a ruler
1. The length of a straight line or of a straight object be measured with a metre ruler.
2. The eye must be vertically above the mark that is to be read. At this position a more
accurate reading can be obtained.
3. A number af readings should be taken to get an average value that is more accurate.

Example:
First reading for length = 4.5 cm
Second reading for length = 4.4 cm
Third reading for length = 4.6 cm
Total length 13.5 cm

Using a measuring tape

1. A measuring tape is used for masuring lengths of several metres.

2. When using a measuring tape ensure that it is stretched between two points.

3. The length is read directly from the scale of the measuring tape.

Using thread and a ruler

1. A length of thread and a ruler are used to measure the lengthof a curved line.
2. Tie a small knot or make with a pen near the end of a piece of cotton thread.
3. Lay the thread along the curved line a tittle at a time.
4. Then, measure the length of the curved line with a ruler.

Example:

First reading for length = 5.5 cm
Second reading for length = 5.4 cm
Third reading for length = 5.6 cm.
Total length = 16.5 cm

Using an opisometer (map measurer)

An opisometer can be used to measure the length of a curved line.

1. The internal diameter of a container like a beaker or boiling tube can be measured using a
pair of internal calipers and a ruler.
2. The distance between the two arms of the calipers marks the inside diameter of the
container.

Example:

1. The external diameter of a container can be measured using a pair of external calipers and a ruler.
2. Measure the distance between the two points of the calipers with a ruler.

Example:

1. The diameter of a spherical object can be measured with:
a) two wooden blocks and a ruler.
b) two set squares and a ruler.

2. Measure the diameter at least three times, turning the spherical object each time and
using a different part of the ruler.

3. Find the average of three measurements.

Example:

1. Vernier calipers can be used to measure small distances or short objects accurately.

2. The internal jaws are used to measure the internal diameter of a container. The external
jaws are used to measure the external diameter of a cantainer.
3. This instrument gives readings with an accuaracy of up to 0.01 cm (2 decimal places).
4. The vernier calipers has two scales. The main scale is graduated in centimetre units. The
vernier scale, a scale of 9 mm, has to 10 divisions. One division is 0.9 mm.

Example: To measure the internal diameter of a container.

5. The vernier calipers can be used to measure short lengths such as the thickness of an eraser. It can also be used to measure the internal and external diameters of object such as a boiling tube, a measuring cylinder, a test tube and the mouth of a conical flask.

1. Area is the total surface or space occupied by an object.

2. Area is measured in square metres (m²), square centimetres (cm²), and square millimetres (mm²) units.

1. Area of a square.
- The area of a square is measured using the following formula.

2. Area of a triangle
-The area of a triangle is measured using the following formula:

Example:

1. The area of irregular shapes like leaves and petals can be estimated by using graph paper.

2. The outline of an irregular figure (leaf) is traced on graph paper.

3. Mark on every square or more than half of the square covered by the figure.

4. The total number of squares marked is counted.

5. The area of the leaf is estimated.

Example:

1. Volume is the total space occupied by an object.

2. Volume is measured in litres (l), millilitres (ml), cubic metres (m³) and cubic centimetres (cm³).

1. A measuring cylinder is used to measure the volume of liquid in cubic centimetres (cm³).

2. A few precautions must be taken when measuring the volume of a liquid:

3. To obtain an accurate reading of the volume of mercury the reading has to be taken above
the curve of the meniscus.

1. A pipette is a measuring instrument of the volume of liquid. It is more accurate than a measuring cylinder.

2. A pump can be used to suck air out of the pipette until the liquid rises above the mark on the tube.

3. Pipette in laboratories are usually used to measure volumes of 5, 15, 20 and 25 ml.

4. The steps for using a pipette to measure the volume of liquid are shown in diagram below.

1. A burette is used to deliver volumes of liquids more accurately than a measuring cylinder.

2. A burette usually has a capacity of 50 cm3, and is graduated from the top down in tenths of a cubic centimetre.

Example:

Initial reading of the burette = 35 cm³ (or ml)
Final reading of the burette = 45 cm³
Volume of water = 45 - 35 = 10cm³
Therefore, the volume of water in the conical flask = 10 cm³

1. A volumetric flask is used to measure a fixed volume of liquid.

2. The neck has a mark on it indicating the fixed volume of liquid it can measure.

3. To obtain the required fixed volume stated on the flask, the lower level of the meniscus must reach the mark.

The volume of regular and irregular shaped solids can be determined by the water displacement method.

1. Water is poured into a measuring cylinder and its volume noted.

2. The solid is then slowly put or lowered into the water till it is completely submerged.

3. The water level rises, and the new reading gives the volume of the water and the solid.

4. The difference between the volume of the water and the solid, and the volume of the water alone, gives the volume of the solid.

Example:

1. The volume of solids can be determined using an eureka can and a measuring cylinder.

2. The solid is gently lowered into the water. Water will flow out of the can into the cylinder.

3. The volume of water that has been displaced is equal to the volume of the solid.
Volume of solid = volume of water in the measuring cylinder.

Concept of Mass

1. The weight of an object is the force of the gravitational pull that acts on the object.
2. The weight of an object can change. It depends on the gravitational force that acts on the object at a given place. Because of this, the weight of an object differs from place to place.
3. The S.I unit for weight is Newton (N).
4. The weight of an object is measured by using a spring balance or a compression balance.

1. The mass of an object is the quantity of matter that is present in the object.
2. The mass of an object is fixed although it may be moved to different places.
3. Mass is different from weight. The mass of an object is not influenced by the force of gravitational pull.
4. The S.I. unit for mass is kilogram (kg). Other units for mass is gram (g) and milligram (mg).