Exam practice
Every question from the end of every unit, with hints and answers to open. After you check an answer, mark how you did, and come back to the ones you didn’t get.
19 questions
Unit 1 · Scientific Learning
1. Fill in the blanks with suitable words
We need to take ……… of a body to know its exact quantity.
Answer
measurement
The interval between any two events is called ……… .
Answer
time
The distance between any two points is called ……… .
Answer
length
The SI unit of area is ……… .
Answer
square meter (m²)
The ……… of a liquid is measured using a measuring cylinder.
Answer
volume
A ……… is drawn after the analysis of data.
Answer
conclusion. (The word “area” is not used.)
3. Match the following
Match each physical quantity with its SI unit.
| Physical quantity | SI unit |
|---|---|
| Length | kilogram |
| Mass | second |
| Time | meter |
| Area | cubic meter |
| Volume | square meter |
Answer
| Physical quantity | SI unit |
|---|---|
| Length | meter (m) |
| Mass | kilogram (kg) |
| Time | second (s) |
| Area | square meter (m²) |
| Volume | cubic meter (m³) |
4. Convert the following
2 hours into seconds
Answer
1 hour = 60 × 60 s = 3600 s, so
2 hours = 2 × 3600 s = 7200 s.
15 kg into grams
Answer
1 kg = 1000 g, so
15 kg = 15 × 1000 g = 15,000 g.
2 m² into cm²
Answer
1 m² = 100 cm × 100 cm = 10,000 cm², so
2 m² = 2 × 10,000 cm² = 20,000 cm².
4 m³ into cm³
Answer
1 m³ = 100 cm × 100 cm × 100 cm = 1,000,000 cm³, so
4 m³ = 4 × 1,000,000 cm³ = 4,000,000 cm³ (forty lakh cm³).
5. Answer the following questions
What is measurement?
Answer
Measurement is the process of comparing an unknown quantity with a standard, known quantity of the same kind. For example, the volume of water in a glass is measured by pouring it into a measuring cylinder and comparing it with the standard volumes marked on the cylinder.
What is an SI unit?
Answer
An SI unit is a standard unit of measurement accepted all over the world. SI units were agreed at a conference of scientists in France in 1960. Examples: the meter (m) for length, the kilogram (kg) for mass and the second (s) for time.
Why was the SI system developed?
Answer
Local units such as the haat, bitta, mana and pathi are not the same in every place or for every person, so measurements made with them don’t agree. This caused problems in trade within a country and between countries, and in science. The SI system was developed so that everyone in the world could use the same reliable, accurate units.
What is volume?
Answer
The space taken up by an object is called its volume. Its SI unit is the cubic meter (m³); the volume of a liquid is usually measured in liters (l) and milliliters (ml).
What kinds of problems would people face if the SI system had not been introduced?
Answer
- The same thing would measure differently in different places, because local units differ.
- Buying and selling would be unfair and full of arguments: a pathi of rice in one village would not equal a pathi in another.
- Trade between countries would be very hard, as each country would use its own units.
- Scientists in different countries could not compare or check each other’s results.
- Machines and their parts made in different places would not fit together.
- Mistakes would happen when changing between units, which can even be dangerous (in medicine doses or aircraft fuel, for example).
What improvements were seen in measurement after standard units were developed?
Answer
- Measurements became uniform: the same everywhere in the world.
- They became reliable: anyone measuring the same thing gets the same result.
- They became accurate, because standard tools such as rulers, measuring cylinders and balances could be made.
- Trade, within a country and between countries, became easier and fairer.
- Scientists everywhere could share and check each other’s work.
- Changing between big and small units became easy, because SI units go up and down in tens, hundreds and thousands.
A father bought a vest and a pair of trousers for his son from the nearby market. When the son tried them on, the vest was too long and the waist of the trousers was a bit tight. State the cause of this problem, and write the solution.
Answer
Cause: the clothes were bought without measuring the son’s body. The father guessed the size just by looking, or by an unreliable measure, and a guess made by looking is often wrong.
Solution: measure the son’s chest, the length of the vest needed, his waist and the length of his legs with a tailor’s tape in a standard unit (cm or inch), and buy clothes of that size. Better still, take the son along and let him try the clothes on before buying, or have them sewn to his measurements.
Show the phases of the scientific learning process in a flow chart. Mention the main features of each phase in the chart.
Answer
Study of surrounding objects or events → Questioning → Guessing the probable answer → Testing → Accumulating the data → Concluding after data analysis → Presenting a report
| Phase | Main feature |
|---|---|
| 1.Study of objects or events | Learning begins by observing the things and events around us that we see, hear or feel (an apple falling). |
| 2.Questioning | Asking what, why or how about them (why did the apple fall?). |
| 3.Guessing the probable answer | Making a guess (hypothesis) that can be tested (which objects will sink?). |
| 4.Testing | Checking the guess by a suitable method; the most important phase. |
| 5.Accumulating the data | Writing down the results of the test, often in a table. |
| 6.Concluding | Analyzing the data and deciding what they show. |
| 7.Presenting a report | Sharing the conclusion with others, by speaking or in writing. |