9th Class Chemistry Unit 12 Empirical Data Collection and Analysis Long Questions and Answers

1.What are our indigenous units of measurement of mass, volume and length?

Indigenous units of measurement can vary widely depending on the specific culture or region being discussed. Here are some common indigenous units of measurement for mass, volume, and length from various cultures:

Mass In many indigenous cultures, traditional units of mass might include items like "stone" or "pound." For example, in some cultures, a "stone" might be used to measure weight, which is equivalent to about 14 pounds.

Volume Volume measurements might involve containers or natural resources. For example, a "basket" or "cup" could be used to measure liquids or grains. The actual volume would depend on the size of the container used.

Length Length might be measured by using body parts or traditional items. For example, a "foot" or "hand" could be used, where a foot might refer to the length of an actual foot, and a hand could refer to the width of a hand, typically around 4 inches.

2.Elaborate difference between Accuracy and Precision.

Accuracy and precision are both ways to measure the correctness of results. They are used interchangeably in everyday life.

i. Accuracy: Accuracy measures how close results are to the true or known value.
Example: The volume of liquid is 26 cm³ A student measures its volume three times and find the result as 27 cm³. The student is not accurate because he has not calculated the exact result

ii. Precision: The closeness of two or more measurements to each other is called precision.
Example: If you weigh a given substance five times and every time you get 3.2kg reading then your measurement is precise but not necessarily accurate.

Dependence Precision is independent of accuracy. A student may be accurate but not precise and vice versa.

The exact mass of an object is 20 g. A student measures it and takes three readings as 17.3, 17.4 and 17.2. The student is considered as precise but not accurate. Similarly, another student measures the mass of the same object and gets readings as 19.8, 20.5 and 19.6. The second student is the more accurate but not precise

3.How can you avoid systematic errors in your measurements?

Systematic error

Definition When we use tools meant for measurement, we assume that they give correct results. However, these tools may not always be right. In fact, they have errors that naturally occur and these errors are called systematic errors.

How to avoid?
Systematic errors may be removed by adding or subtracting a constant adjustment given to each measurement. Systematic error affect the accuracy of the measurement. All measuring instruments contribute to systematic error e.g. pipette, burette and measuring cylinder may deliver the volume slightly different from the one indicated by their graduation.

4.How do taking measurements in SI units ensure safety and reliability?

One of the most usual problem which is faced by the scientific community is the issue of unit. If scientists in one country are measuring lengths in meters and in another country in feet, then we will have to face problems in converting them. Comparing quantities in different units is not only confusing but the wastage of time as well.

SI Unit Scientists have agreed to adopt standard and user-friendly units called SI or System International Units. Things become a lot easier when we use these units.

Advantage of SI Unit The adoption of SI units is important in all branches of science. It has following advantages:

It makes communication easy worldwide.
It allows scientists to share data easily.
SI units are preferred because they reduce the number of conversions needed to coordinate information among the scientists.
SI units use base 10, just like our number system. So, it is much easier to learn, remember and convert these units. These units are based on definite and precise standards. SI units are interrelated in such a way that one unit is derived from other units without conversion factors.
SI units are used almost everywhere in the world. It allows scientists to use a single standard in exchanging scientific data. This fact brings accuracy, consistency and universal understanding in scientific communication.
A measurement taken in part of the world can be easily understood and verified in another part without any confusion.

5.Can a student be both inaccurate and imprecise in his measurements?

Precision is independent of accuracy. A student may be accurate but not precise and vice versa. Let's suppose the exact mass of an object is 20 g. A student measures it and takes three readings as 17.3, 17.4 and 17.2. The student is considered as precise but not accurate. Similarly, another student measures the mass of the same object and gets readings as 19.8, 20.5 and 19.6. The second student is the more accurate but not precise

6.Elaborate the importance of using SI units in space exploration.

Using SI units in space exploration is crucial for several reasons:

Standardization Space missions often involve collaboration among various countries and organizations. By using SI units, scientists and engineers ensure that everyone is on the same page regarding measurements. This standardization helps avoid misunderstandings that could arise from using different measurement systems, which is vital when dealing with complex technologies and systems.

Precision and Accuracy SI units are based on decimal systems, which make calculations more straightforward and reduces the risk of errors. In space exploration, where precision is critical for navigation, communication, and data analysis, using a consistent and precise measurement system is essential.

For example, distances in space are often measured in kilometers or meters, which allows for accurate calculations when plotting trajectories or determining the positions of spacecraft.

International Collaboration Space exploration is a global endeavor with many missions involving multiple countries. Using SI units facilitates international cooperation by providing a common framework for scientific communication. This is especially important in joint missions, such as the International Space Station, where teams from different nations work together.

Data Comparison and Sharing The use of SI units allows for easier comparison of data collected from different missions. When data is reported in a standardized format, researchers can effectively analyze and share findings across various studies, enhancing the overall understanding of space Phenomenon.

Educational Consistency SI units are taught in educational institutions worldwide, making them familiar to scientists and engineers entering the field. This consistency in education helps prepare future generations for careers in space exploration and related fields.

7.Compare SI units with imperial system of units.

Unit 12: Empirical Data Collection and Analysis — Long Questions