Points to Remember, Glossary, Concept Map

Points to Remember

* The need of standard units for physical quantities was recognised in the 11th General Conference on Weights and Measures in 1960.

 * Length, mass, time, temperature, electric current, amount of substance and luminous intensity are called base quantities.

* Temperature is the measure of hotness or coldness of a substance. Its SI unit is kelvin.

* Electric charge is measured in coulumb and electric currect is measured in ampere.

* The SI unit of amount of substance is mole.

* Luminous intensity is measured in candela.

* Quartz clock uses the ‘electronic oscillations’ controlled by a ‘quartz crystal’.

* Atomic clock uses the ‘periodic vibrations occurring within the atom’.

* Accuracy is the closeness of a measured value to the actual value.

* Precision is the closeness of two or more measurements to each other.

 * Approximation is the process of finding the solution by means of ‘estimation’.

GLOSSARY

1. Amount of substance Measure of number of entities (particles) present in a substance.

2. Calibration Process of configuring an instrument in a particular range.

3. Electric current Flow of electric charges (electrons) in a unit time.

4. Electronic Oscillation Oscillations produced by an electronic circuit.

5. Luminous Intensity Amount of light emitted by a light source in a particular direction per unit time.

6. Plane angle Angle made at the point of intersection of two lines or planes.

7. Quartz Crystal Crystal formed by Silicon and Oxygen (SiO₂).

8. Solid angle Angle made at the point of intersection of three or more planes.

REFERENCE BOOK

1. Units and Measurements – John Richards, S. Chand publishing, Ram nagar, New Delhi.

INTERNET RESOURCES

1. h t t p : / / w w w. n p l . c o . u k / r e f e r e n c e / measurement-units/

2. http://www.splung.com/content/sid/1/page/units

Concept Map

ICT CORNER

Measurement

This activity enables the students to learn about the various types of Time keeping devices

Steps

* Open the Browser and type URL link given below (or) Scan the QR Code.

* Click and select the “History of time keeping devices”

* Options will be given. Select any content (Eg) Digital clock

* It gives clear understanding of the “History of time keeping devices”

Web link: https://playablo.com/Blog/5-fun-activities-to-teach-temperature-hot-and-cold-to-preschoolers/https://en.wikipedia. org/wiki/History_of_timekeeping_devices

(or) scan the QR Code

*Pictures are indicative only