Table of Contents
Unit 1 Measurement 5-10
Unit 2 Matter 11-48
Unit 3 Basic materials for maintaining life Air 49-54 Water 55-68 Food 69-71 Other biomolecules of life 72-76
Unit 4 Energy in the Community Electricity 77-78 Heat 78-81 Light 82-91 Sound 92 Simple Machines 93-99
Unit 5 The Physical Environment Weather and Climate 100-113 Soils 114-128
Unit 6 Living things in the Environment
Plant and animal cells 129 Eukaryotes vs prokaryotes 130 Structures and functions 133-137
Onion and cheek cells 150-151
Ecological study 154
Seed …show more content…
* spurious digits introduced, for example, by calculations carried out to greater accuracy than that of the original data, or measurements reported to a greater precision than the equipment supports.
The concept of significant figures is often used in connection with rounding. Rounding to n significant figures is a more general-purpose technique than rounding to ndecimal places, since it handles numbers of different scales in a uniform way. For example, the population of a city might only be known to the nearest thousand and be stated as 52,000, while the population of a country might only be known to the nearest million and be stated as 52,000,000. The former might be in error by hundreds, and the latter might be in error by hundreds of thousands, but both have two significant figures (5 and 2). This reflects the fact that the significance of the error (its likely size relative to the size of the quantity being measured) is the same in both cases.
Computer representations of floating point numbers typically use a form of rounding to significant figures, but with binary numbers.
Identifying significant digits
The rules for identifying significant digits when writing or interpreting numbers are as follows: * All non-zero digits are considered significant. For example, 91 has two significant figures (9 and 1), while 123.45 has five significant figures (1, 2, 3, 4