UNIT 1: SCIENTIFIC STUDY
Multiple Choice Questions (MCQ): 1
Mark Each
1)
In
an experiment to determine the effect of temperature on plant growth, which of
the following is the independent variable?
a)
Plant growth b) Temperature c) Soil type d) Watering frequency
2)
In
a study on the relationship between exercise and heart rate, which of the
following is the dependent variable?
a)
Exercise b) Heart rate c) Age d)
Gender
3)
Which
of the following is an example of a dependent variable in a study on the
effects of caffeine on cognitive performance?
a)
Amount of caffeine consumed b) Time
of day
c)
Cognitive performance d)
Age of participants
4)
A
researcher is conducting a study to determine the effect of sleep on mood.
Which of the following is the independent variable?
a)
Mood b) Amount of
sleep c) Gender d)
Age
5)
In
a study on the effects of noise on memory, which of the following is the
independent variable?
a)
Memory b) Age c) Noise
level d) Gender
6)
In
a study examining the effect of a new medication on blood pressure, which of
the following is an example of a controlled variable?
a)
Age of participants b)
Gender of participants
c)
Dosage of medication d)
Time of day blood pressure is measured
7)
In
an experiment testing the effect of different fertilizers on plant growth,
which of the following is an example of a controlled variable?
a)
Type of fertilizer b) Amount of
sunlight c)
Temperature d) Type of
plant
8)
In
a study investigating the effect of exercise on weight loss, which of the
following is an example of a controlled variable?
a)
Type of exercise b) Duration of
exercise c) Diet of participants
d)
Age of participants
9)
In
a study examining the effect of temperature on the rate of chemical reactions,
which of the following is an example of a independent variable?
a)
Type of chemical reaction b) Temperature c) Pressure d) Time
10) In a study on the effects of caffeine on
memory, why is it important to have a control group?
a)
To
ensure that the results are statistically significant
b)
To
prevent confounding variables from affecting the results
c)
To
make the study more interesting to readers
d)
To
save time and resources
11) Which of the following is an example of a
derived unit?
a)
Kilogram b) Second c) Newton d)
Meter
12) What is the SI unit for measuring electric
current?
a)
Kelvin b) Joule c) Ampere d)
Newton
13) Which of the following is an example of a
derived unit?
a)
Second b) Meter c) Hertz d)
Kelvin
14) What is the SI unit for measuring force?
a)
Kilogram b) Newton c) Joule d)
Pascal
15) What is the dimension formula for
velocity?
a)
[M L-1T2] b)
[M L2 T-2] c)
[M2L2T-1] d)
[M L T-1]
16) What is the dimension formula for power?
a)
[M L2 T-2] b)
[M L2 T-3] c)
[M L T-2] d) [M L2 T-1]
17) What is called for the causative factor,
characteristics or trait that has direct or indirect relationship with an event
or a phenomenon?
a)
Hypothesis b) Experiment c) Scale d) variable
18) An independent variable can be defined
as……………….
a)
Extraneous
variable b) Change variable c) outcome/effect variable d) Confounding variable
19) Scientists wanted to determine the colour
of flower that bees are most attracted. They placed different colours of the
same type of flower near each other and counted the number of bees that visited
each flower. What is independent variable.
a)
Types
of bees b) Type of flower c)Colour of flower d) Number of bees
20) In regard to symbols used in research
methods, which of the following represent independent variable?
a)
X b) Y c) Z d)
None of these
21) a
Answer:
1(b), 2 (b), 3 (c), 4 (b), 5 (c), 6(c), 7(d), 8(c), 9(b), 10(b), 11(c), 12(c),
13(c), 14(b), 15(d), 16(b), 17(a), 18(b), 19(c), 20(a)
Very Short Answer Questions. [1 marks each]
1.
What
is scientific learning?
Scientific
learning is the process of acquiring knowledge and understanding of the natural
world through the use of scientific methods, including observation,
experimentation, and analysis.
2.
What
is the objective of scientific learning?
The
objective of the scientific learning is to develop an understanding of the
natural world that is accurate, reliable and supported by evidence.
3.
Define
variable.
A
variable is a characteristic or property of an object or phenomenon that can be
measured, observed, or manipulated. Variables can take on different values or
levels and can be either quantitative (numerical) or qualitative (categorical).
4.
How
many types of variables are there? What are they?
There
are three types of variables. They are independent, dependent and control
variables.
5.
What
is independent variable?
An
independent variable is a variable that is intentionally manipulated or changed
by the researcher in an experiment to observe the effect on the dependent
variable.
6.
What
are the other names of independent variable?
The
other names of independent variables are experimental variable or predictor
variable.
7.
Which
variable is the cause of change in another variable?
Independent
variable is the cause of change in another variable.
8.
What
are dependent variable?
A
dependent variable is a variable that is observed or measured in response to
changes in the independent variable. It is the outcome or effect that is being
studied.
9.
What
do you meant by control variable? [SEE 2080, KP]
A
control variable is a variable that is held constant or kept consistent
throughout an experiment to ensure that any observed changes in the dependent
variable are due to changes in the independent variable and not to other
factors.
10. What is hypothesis?
A
hypothesis is a tentative explanation or prediction for an observed phenomenon
or relationship between variables. It is based on prior knowledge or research
and can be tested through experimentation.
11. Give an example of dependent variable.
An
example of a dependent variable could be the height of plants in an experiment
testing the effect of different fertilizers on plant growth.
12. Give an example of independent variable.
An
example of an independent variable could be the temperature in an experiment
testing the effect of temperature on the rate of chemical reactions.
13. What do you mean by dimension of a
physical quantity?
The
dimension of a physical quantity refers to the nature of the quantity and the
units used to express it.
14. What is the unit to measure the magnitude
of earthquake?
The
unit to measure the magnitude of earthquake is Richter scale.
15. What is a unit?
The
reference standard with which we carry out the measurement of any physical
quantity of the same kind is called unit.
16. What are fundamental unit? Give some
examples.
The
units of fundamental quantities are called fundamental units or basic units.
Some examples of fundamental units are meter, kilogram, second, etc.
17. What are derived units? Give some
examples.
The
units of derived quantities are called derived units. Some examples of derived
units are meter per second, meter square, etc
18. State the principle of homogeneity?
The
principal of homogeneity states that an equation is correct if the unit of
various terms on either side of the equation are same.
19.
A student wanted to test how the mass of a paper airplane affect the
distance it would fly. Paper clips were added before each flight. As each paper
clip was added, the plane was tested to determine how far it would fly.
Identify the depended and independent variables.
The mass of the plane is independent variable and distance covered
by the plane is dependent variable.
20.
What are the combination of base units in power?
The base units in power is Kg×m2×s-3.
21.
The unit of work is derived unit, why?
The unit of work is joule which is made by the combination of
fundamental units i.e. kg m and second.
Joule = N×m
or Joule = Kg×m×s-2×m
or Joule = Kg×m2×S-2.
Thus, the unit of work i.e. Joule is made by the combination of
multiples of kg, m and second. So, the unit of work is derived unit.
22.
Why there is necessity of unit wise analysis?
There is necessity of unit wise analysis to validate the equation.
23.
An experiment was performed to determine how the amount of coffee
grounds could affect the taste of coffee. The same kind of coffee, the same
percolator, the same amount and type of water and same perking time and same
electric source were used. Identify the independent and dependent variable.
Amount of coffee grounds is independent variable and taste of coffee
is dependent variable.
24. Students of different age were given the
same puzzle to assemble. The puzzle assembly time was measured. Name the
dependent and independent variable involved in it.
Age
of students is independent variable and assembly time of puzzle is dependent
variable.
25. What do you mean by dimension of a
physical quantity?
Dimension
of a physical quantity can be said as the power to which the fundamental units
must be raised to obtain one unit of that physical quantity.
26. What fundamental units are used in the
unit of pressure? [SEE 2080 MP]
The
fundamental units involved in the unit of pressure are kg, m and s or Kgm-1s-2.
27. Write the fundamental units included in
the unit of force. (SEE 2081, LP)
The fundamental units included in
the unit of force:
The
unit of force is Newton (N), which is derived as:
Force=Mass
× Acceleration
In
terms of units:
Mass → Kilogram (kg)
Acceleration → Meter per second squared (m/s²)
Therefore,
Newton (N) = kg × m/s²
Thus, fundamental units included in the
unit of force are Kg, m and S.
28.
Short Answer Questions: [2 marks each]
1.
What
are the steps that should be followed by a researches in scientific learning?
The
series of steps that should be followed by a researchers in scientific learning
are:
Making
an observation, asking a question, formulating a hypothesis, making a
prediction on the basis of hypothesis, conducting an experiment, analysis the
result and finally drawing a conclusion.
2.
Controlled
variables are important in scientific learning, why?
Controlled variables are not involved in
an experiment but they are very important because it can have an effect on the
result. If these variable are not constant throughout the experiment, they may
cause a great error in the result of experiment. The result may be bias if the
controlled variables have unequal effect on any experiment. For example, if we
want to test the effect of temperature on growth of plant, other variables such
as light, fertilizer, humidity, altitude, air, water, etc. are kept constant.
3.
How
do you identify the independent and dependent variable?
In
order to identify the independent and dependent variable, the independent
variable is the one that can be change as per required by the experiment and
the dependent variable is one which changes due to the effect of independent
variable. It means that independent variable is the cause and dependent
variable is the effect.
4.
Why
is homogeneity required in scientific research?
In
scientific research, homogeneity in units of measurement is critical to
ensuring accurate and consistent results.
5.
What
do you mean by parameter in scientific learning? Give an example.
In
scientific learning, a parameter is a measurable quantity that characterizes a
system, process, or phenomenon.
For
example, in an experiment to study the growth of plants, the amount of
sunlight, water, and nutrients are some of the parameters that can be measured
and controlled to understand their effect on plant growth.
6.
Why
is the unit of length called a fundamental unit and the unit of area called a
derived unit?
The
unit of length is called a fundamental unit because it is a basic, fundamental
measurement that cannot be derived from any other physical quantity. On the
other hand, the unit of area is a derived unit because it can be calculated by
multiplying two lengths together. For example, the area of a rectangle can be
calculated by multiplying its length and width. Therefore, the unit of area is
a derived unit that is expressed in terms of the fundamental unit of length.
7.
Why
is the unit of speed called a derived unit?
The
unit of speed is meter per second or m/s. It depends on two fundamental units
i.e. unit of length (meter) and unit of time (second). Hence, the unit of speed
m/s is a derived unit.
8.
The
unit of pressure is derived unit. Justify.
The
unit of pressure is Pascal i.e. Newton per square meter
We
know that,
Pressure
=
i.e.
Substituting
the related units in the above equation (i)
Pascal
=
The
unit of Pressure i.e. Pascal depends upon fundamental units i.e. kg, m and s.
Therefore, it is a derived unit.
9.
Why
is analysis of unit necessary?
The
analysis of units is necessary for ensuring accuracy, facilitating
communication and data sharing, enabling conversions between different units,
preventing errors and confusion, and facilitating mathematical operations. .
10. What is unit of work? Explain whether the
unit of work is fundamental or derived unit.
The
unit of work in Joule. It is the product of newton and displacement.
Furthermore, Newton is derived from the product of Kg and m/s2.
Therefor the fundamental units involved in the joule is
Joule
=
=Kgm2s-2..
Here, in the unit of joule is formed by the combination of Kg, m and sec.
Therefore, the unit of work is derived unit.
11. Write the SI unit of following physical
quantity.
a)
Potential difference b) temperature c) Electric current d) Moment
The
SI unit of the above physical quantity are:
|
Physical Quantity |
SI Unit |
|
a) Potential difference |
Volt (V) |
|
b) Temperature |
Kelvin (K) |
|
c) Electric current |
Ampere (A) |
|
d) Moment |
Newton meter (Nm) |
12. Prove that: electrical resistance (Ω) = kgm2s-3A-3.
We know
that the SI unit of resistance is Ohm(Ω). If 1 A of current flows
through the ends of a conductor when the two ends are kept at 1 V of potential
difference, the resistance of the conductor is defined as 1 Ohm.
1
Ω = 1V/1A
In
terms of fundamental units, Ohm can be expressed as,
Ω =
In terms of fundamental units:
=Kg.m2.A2/s3
=kg.m2.s-3.A2
13. Why is mass called a physical quantity?
Mass
is called a physical quantity because it is measured by using some instruments
like beam balance or weighing machine.
14. Write the differences between fundamental
and derived units.
The
difference between fundamental and derived units are:
|
Fundamental units |
Derived units |
|
1. It is independent of the other
units of measurement. |
It depends on other units of
measurement. |
|
2. The number of fundamental
units are fixed i.e. 7 in SI system. |
The number of derived units is
not fixed in SI system. |
15. What are the different steps used in
scientific study? Show in a flow chart.
16. Write two reasons for controlling
variables in research.
17. Hari claims the formula of density D =m/v
and pressure P =F×A. Check the analysis of unit wise equation given by hari.
18. Complete the given table using independent
variable, dependent variable and control variable.
|
SN |
Experiment |
Independent variable |
Dependent variable |
Controlled variable |
|
1 |
|
|
|
|
19. Write a short note on SI system of
measurement.
20. Mention any two applications of
dimensional analysis.
21. A student has to test the interrelation
between growth of plants and availability of sunlight. What will be the
independent variable and the controlled variable of the test? [SEE 2080 BP]
In
this experiment, the independent variable is the availability of sunlight. This
variable is deliberately manipulated by the researcher to observe its effects
on the growth of plant. One controlled variable could be the type of plant
species used in the experiment.
22. A student has to test the change in effort
applied and the number of pulleys used. In this experiment
Long Answer Questions: [4 marks each]
1.
Clarify
different types of variables giving an example of experiment.
There
are three types of variables. They are:
a)
Independent
variable: The independent variable is the variable that can be change in
an experiment.
b)
Dependent variable: The dependent
variable is the variable that can be measure in an experiment. It is the
variable that is believed to be affected by the independent variable.
c)
Controlled variables: Controlled
variables are variables that are kept the same in an experiment. They are
important because they can affect the dependent variables.
In
an experiment, to test the effect of fertilizer on the growth of plants, amount
of fertilizer is independent variable, height of the plant is dependent
variable while amount of water, type of soil, amount of sunlight, etc. are
controlled variable.
For
this experiment 5 potted plants of equal height are taken. In this experiment,
different amount of fertilizer is given to each plant and then the height of
each plant is measured after a certain amount of time. The dependent variable
is the height of the plants. Our expectation is that the plants that received required
quantity of fertilizer would be taller than the plants that received less
quantity fertilizer. The controlled variables are the amount of water, the type
of soil, and the amount of sunlight that the plants receive. These variables
are kept the same for all of the plants, so that the only difference between
the groups is the quantity of fertilizer.
2.
Why
are variable important in scientific study. Give four reasons.
Variables are important in scientific study because they are
the basic units of information studied and interpreted in research studies.
Researchers carefully analyze and interpret the value(s) of each variable to
make sense of how things relate to each other in a descriptive study or what
has happened in an experiment.
a)
Variables help researchers measure cause and effect in
scientific experiments.
b)
Variables allow scientists to manipulate cause and effect to
produce desired outcomes.
c)
Variables help
researcher to design experiment that can test their hypothesis.
d)
Variables help researchers identify patterns and
relationships between different phenomena
3.
Differentiate
between fundamental unit and derived unit in any four points.
The
differences between derived unit and fundamental units are as follows.
|
Fundamental
Unit |
Derived
unit |
|
1.
This
is the unit of fundamental quantity |
1.
This
is the unit of derived quantity. |
|
2.
This
unit is independent of the other units. |
2.
This
unit depends upon two or more fundamental units |
|
3.
There
are only seven fundamental units |
3.
There
are several derived units. |
|
4.
Examples
of fundamental units are meter, kilogram, second, ampere, etc. |
4.
Examples
of derived units are Newton, Pascal, Watt, Hertz, etc |
4.
Abdul
Kalam wants to test the effect of light on growth of plants. He takes three
potted plants of same kinds and marked A, B and C. He keeps pot A in open space
where there is sufficient sunlight, pot B in the dim light and Pot C in
complete dark for 15 days. He supplies equal amount of nutrients and water to
all the pots. After 15 days he observes each of the potted plants. Answer the
following questions based on this experiment.
i.
Write
the independent variable and dependent variable.
The independent variable
is the amount of light received by the plants, and the dependent variable is
the growth of the plants.
ii.
Which
variable should be controlled by Abdul? Explain.
Abdul should control the
amount of nutrients and water supplied to the plants because any variation in
these factors could affect the growth of the plants and influence the results.
iii.
What
is the hypothesis of this experiment?
The hypothesis of this
experiment is that the amount of light received by a plant affects its growth.
iv.
How
might Abdul extend this experiment to test other factors that affect the growth
of plants?
Abdul could extend this
experiment to test other factors that affect the growth of plants, such as the
type and amount of nutrients, the frequency and amount of watering, the
temperature, and the humidity. To do this, he could set up different groups of plants
and vary the factor of interest while keeping all other factors constant. He
could then compare the growth of the different groups of plants to see how the
factor being tested affects their growth.
5.
Dayaram
Tiwari has a cow farm. He divided the cows in two group. He increased the
protein containing food to one group and gave normal food to the other group.
The group of cows supplied with protein containing food gave more milk than the
other. Write the dependent and independent variables with reasons. What are the
constant variables in this experiment?
The
independent variable in this experiment is the type of food given to the two
groups of cows. Dayaram Tiwari changed the type of food given to each group to
see how it affected their milk production.
The
dependent variable is the amount of milk produced by each group of cows. This
is the variable that is affected by the independent variable, i.e., the type of
food given to each group.
The
constant variables in this experiment could be the breed, age, and health of
the cows, the amount of food given to each group, the environment, and the
duration of the experiment. These variables were kept constant to ensure that
any differences in milk production were due solely to the type of food given to
each group.
6.
Mention
any four importance of controlled variable.
Four
importance of controlled variable are:
a)
To
establish a causal relationship between the independent and dependent
variables.
b)
To
increase the internal validity of an experiment.
c)
To
make it easier to reproduce the experiment
d)
To
reduce the risk of bias.
a)
How
is homogeneity and validity of an equation measured? Describe with any two
examples.
Homogeneity
and validity of an equation is measured applying the principle of homogeneity
of units. It implies that if the unit of various terms on either side of
equation are same then an equation is correct.
Example:
Let us consider the physical equation V = u + at, where u is the unit of
velocity, v is the final velocity, a is the acceleration and t is the time. In
order to check its homogeneity, we have to check both the left and right hand
side using valid units.
Here,
LHS
= V and in terms of unit,
V
= ms-1 ………………(i)
Similarly,
RHS
= u + at = ms-1+ ms-2×s1
Or
u+ at = ms-1+ms-1 ……………(ii)
From
equation (i) and (ii), unit of LHS = unit of each term in RHS
Hence,
from the principle of homogeneity of units, the given equation is dimensionally
valid.
Second
example.
P
= hdg where P = pressure, h = depth, d = density and g = acceleration due to
gravity
LHS
= P = F/A = m×a/A
In
terms of units, kg×ms-2/m2 = kgm-1s-2
…………..(i)
RHS
= dgh = kgm-3×ms-2×m = kgm-1s-2…………..(ii)
From
equation (i) and (ii), LHS = RHS.
Therefore,
the homogeneity of unit is valid.
b)
In
the experiment below a researcher is testing the effect of effort distance of
the slanted surface on the effort applied to lift up the load.
a)
Which
one is independent and dependent variables in this experiment? Give reason.
In this experiment effort
distance is independent variable. This is because the researcher wants to
change effort distance. Effort applied to lift up the load is dependent
variable because effort applied changes with the change in effort distance or
in other words effort applied depends on effort distance.
b)
Which
variables have to be controlled in this experiment?
Amount of load and load
distance are the variables that have to be controlled in this experiment.
c)
If
the researcher wishes to test effect of load distance on effort applied, which
one would be independent and dependent variable?
If the researcher wishes
to test effect of load distance on effort applied, load distance would be
independent variable and effort applied would be dependent variable.
c)
a
Glossary:
|
Variable |
Factor or condition that can be changed or modified. |
|
Independent variable |
A variable that can be manipulated, varied or
changed. |
|
Dependent variable |
A variable that depends upon the independent
variable. |
|
Controlled variable |
A variable that does not change in an experiment |
|
Unit |
A reference value used to measure physical quantity |
|
Fundamental unit |
A unit that is independent of other units. |
|
Derived unit |
A unit that is derived from other physical units |
|
Physical quantity |
The quantity that can be measured by using some
devices |
|
Fundamental unit |
The units which are independent of the other units
of measurement. |
|
Unit analysis |
The study of relation between the physical quantity
with the help of unit of measurement. |
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