Measurement | Chapter 1 | 8th Science - Student Activities | 8th Science : Chapter 1 : Measurement
Chapter: 8th Science : Chapter 1 : Measurement
Student Activities
Activity 1
Measure the length and breadth of your science book using a ruler (scale) and 8 compare your value with those of your friends.
Students arc asked to measure the length and breadth of their science book using a ruler (scale) and compare their measurement with those of their friends.
Answer:
Aim : To determine the length and breadth of science book and to understand magnitude and unit.
Apparatus required: Science book and ruler (scale)
Tabular column:
Name of the object : Science textbook
Length (cm) : 25
Breadth (cm) : 21
Inference :
The length of science book l = 25 cm
The breath of science book b = 21 cm
Here, 25, 21 is the magnitude (number value) cm is the unit.
ACTIVITY
Measure the room temperature inside the class room and outside the class room by using a thermometer and tabulate it with different time intervals for a week. Do you find any differences in these values? Discuss your observations.
Answer:
Aim : To measure the room temperature inside the class room and outside the class room at different time intervals for a week.
Materials required : Thermometer.
Procedure :
(i) With the help of a thermometer, note down the room temperature inside and outside the class room at different time intervals of a day.
(ii) Repeat the process for 5 days.
(iii) Note down the temperature in the tabular column.
Inference:
(i) Temperature varies at different time intervals.
(ii) It varies from place to place.
Activity 2
From the news paper or television, collect the highest and lowest temperature experienced in your nearest town or city for a week and record the values in a tabular column. Does this data remain same throughout the year?
Collect
the highest and lowest temperature details of your nearest town or city from
the news paper or television for a week and record the values in a tabular
column. Does this data remain same throughout the year?
Inference: The data (temperature) does not remain same throughout the week.
Activity 3
Connect a battery, an ammeter and a lamp in series as shown in the figure. Note the ammeter reading. It is the amount of current flowing in the circuit.
Measure the current in an electric circuit.
Answer:
Aim: To measure the current in an electric circuit.
Components required: Battery, Ammeter and Lamp (Bulb).
Procedure :
(i) Connect the battery, ammeter and the lamp in series as shown in the figure.
(ii) Note the ammeter reading.
(iii) It is the current in the circuit.
Inference: Current is measured by using ammeter in an electric circuit.
ACTIVITY
Observe
the ‘Rasam making’ process in your home. Ask your elders and try to answer the
following questions:
(i) The
rasam is made for how many persons?
(ii) How
could you increase the taste?
(iii) How
much of salt has to be added?
(iv) Is
there any prescribed standard for taking the ingredients?
Answer:
(i) 4 persons.
(ii) By adding pepper, jeera and coriander leaves.
(iii) Approximately one and half table spoon.
(iv) No, there is no prescribed standard for taking the ingredients.
While we prepare a dish, the ingredients are taken approximately.
Info bits
Luminous flux or Luminous power is the measure of the perceived power of light. Its SI unit is ‘lumen’.One lumen is defined as the luminous flux of the light produced by the light source that emits one candela of luminous intensity over a solid angle of one steradian.
Activity 4
Make a model of an analog clock using card board.
Activity 5
Make a model of a digital clock using match sticks on a card board, with date and time.
Activity 6
You may have heard about the ‘Sun Dial’. Construct a sundial of your own and read out the values from morning to evening. Compare your values with modern clocks.
Greenwich Mean Time (GMT)
is the mean solar time at the Royal Observatory, located at Greenwich in London. It is measured at the longitude of zero degree.The Earth is divided into 24 zones, each of a width of 15 degree longitude. These regions are called as ‘Time Zones’. Time difference between two adjacent time zones is 1 hour.
Indian Standard Time (IST)
The location of Mirzapur in Uttar Pradesh is taken as the reference longitude of the Indian Standard Time. It is located at 82. 5 degree longitude. IST = GMT + 5:30 hours
Activity
Calculate the approximate ‘heart beat’ of a man in a day (Hint: Take number of heart beats per minute as 75, approximately).
Calculate the approximate ‘heart beat’ of a man in a
day. (Hint: Take number of heart beats per minute as 75, approximately)
Solution :
Number of heart beats per minute = 75 (approx.)
Approximate heart beat of a man in a day = ?
1 hour = 60 minutes
1 day = 24 hours
= 75 × 24 × 60
Approximate heart beat of a man in a day = 1,08,000
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