Measurements, units and Uncertainty in physics

In physics, measurement refers to the process of quantitatively determining the properties of an object or phenomenon, such as length, mass, time, temperature, or electric current. Measurements are essential for experiments and observations, allowing scientists to describe and analyze the physical world.

1. Measurements in Physics

2. Defining Unit in Physics The things that we can measure is Physical Quantities for examples: length, speed, weight, time, current, etc. How to define this Physical Quantities so it can be measurable? The propose of measuring quantities is to know how big these things. In physics we cannot say “Wow that building is very tall” but you have to specify what its mean by “really tall”? Each person has relative sense. Might be one person will say “this box is heavy” but another person would say not. Here, we have to set a reference called Unit .

3. Standard International (SI) Unit is reference for measuring a physical quantity. The worldwide standard for units is known as SI has set sevens fundamental quantities and fundamental units. Fundamental means that these are very basic quantities and we can do many calculation from these quantities. One example is mass and as a reference scientists had decided kilogram (kg) as the unit of mass. where 1 kilogram is defined as mass equal to the mass of the international prototype of the kilogram kept at the Bureau International des Poids et Mesures at Sèvres, near Paris.

4. https://physicsworld.com/a/new-definition-of-the-kilogram-comes-into-force/

5. Fundamental Quantities and Unit

6. So many things in physics but only 7 units are displayed in the previous slide. Do you recognize the other units besides the fundamental one?

7. Derived quantities & units   Fundamental Unit of Speed Where speed itself is a derived quantities

8. Derived quantities & units   Based on this derived formula, the unit of the force will be the combination of the unit of mass, displacement, and time  

9. Can you find the fundamental units for the following quantities? Frequency = Potential Energy = Power = Pressure =  

10. Derived Quantities Quantities Unit Symbol Fundamental Unit Force Newton N Pressure Pascal Pa Energy Joule J Power Watt W Frequency Herz Hz Electric Potential Volt V Resistance Ohm Ω

11. Significant Figures We will have a big deal of calculation here we need to know the total number of significant figures. Significant means are meaningful. For example 9234, the most significant is 9 because it tells as a nine thousand something and the second is 2 because it tells as a two hundred something and also 3 and 4. All non-zero numbers are significant Zeros in the left side are not significant because its function is only to put decimal. Zeros numbers between non-zero is significant. Trailing zeros are significant only if the decimal point is specified.

12. Examples: 34578 0.00035 0,1007 300 300. 34.0250   5 sf 2 sf 4 sf 1 sf 3 sf 6 sf 4 sf 4 sf 6 sf 1 sf 4 sf 2 sf

13. Answer the following questions Type in the chat option to answer the following questions! State 7 fundamental quantities followed by their units State 3 minimum derived quantities followed by their units How many sf the following number has? 0.00020 450.100 0.225 5000.001 110000 2sf 6 sf 3 sf 7 sf 7 sf

14. Scientific Notion  

15. The Rules of Scientific Notion  

17. Write the number using scientific notation with 3 SF: 14356000000000000000000 = 5676320000000000000 = 0.0000000000003002708 = 4445200000000000000000000 = 0.000000000003450056 =