Knewton Chapter 1: SI Units for Temperature and Time

Study Notes

Temperature

Intensive property measuring heat energy in an object.
SI unit for temperature: kelvin (K), no degree symbol used.
Water freezes at 273.15 K and boils at 373.15 K.
0 K represents absolute zero, a theoretical point where all motion ceases.

Celsius

Celsius (°C) is also recognized in the SI system; uses degree symbol.
Water freezes at 0°C and boils at 100°C.
1 K is equal to 1°C.

Temperature Conversion

To convert Celsius to Fahrenheit, use: F = (9F/5C) x (C) + 32F.
To convert Fahrenheit to Celsius, use: C = (F - 32F) x (5C/9F).

Time

Measurement of process duration.
SI base unit: second (s).
Time intervals can be expressed in various prefixes:
- Microseconds (3 µs = 3 × 10−6 s)
- Megaseconds (5 Ms = 5 × 10^6 s).

Scientific Notation

Format: a single digit followed by a decimal and additional numbers.
Expressed as a number multiplied by 10 raised to an exponent.

Newton

Unit of force defined as [(kg)(m)]/s².

Base Units of the SI System

Length: meter (m)
Mass: kilogram (kg)
Time: second (s)
Temperature: kelvin (K)
Electric current: ampere (A)
Amount of substance: mole (mol)
Luminous intensity: candela (cd)

Length

Represents distance traveled; measured in inches, feet, yards, miles, and meters.
Small distances expressed in millimeters; large distances in kilometers.

Volume

Amount of space occupied by an object, primarily measured in liters.

Mass

Defined as the amount of matter in an object; measured in kilograms (kg).
Originally based on the mass of a liter of water, now referenced by a metal cylinder stored in France.

Specific Gravity

Formula: specific gravity = (density of sample substance / density of reference substance).
Comparative measure of density against a standard.

Water Density

Density of water is 1 g/ml or 1 g/cm³.

Dimensionless Quantity

A type of measurement without physical dimension, also known as a quantity of dimension one.
Common in mathematics, physics, engineering, and economics.

Density

Defined as mass per unit volume.
SI units: kg/m³; also expressed in g/cm³ or g/mL.
Calculation: Density = Mass / Volume.

SI Units Overview

Key SI units:
- Kilogram (kg) for mass
- Second (s) for time
- Kelvin (K) for temperature
- Ampere (A) for electric current
- Mole (mol) for amount of substance
- Candela (cd) for luminous intensity
- Meter (m) for distance

Conversion Factors

Kilo (10³)
Mega (10⁶)
Giga (10⁹)
Tera (10¹²)

Kilogram

Originally based on the mass of a liter of water, now defined using a stable standard cylinder.

Meter

Originally defined as a fraction of the Earth’s distance from the equator to the pole, now universally revised.

Description

This flashcard set focuses on identifying and using the SI units for temperature and time, specifically through the lens of Knewton Chapter 1. Students will learn key definitions and properties, including the significance of the kelvin in scientific contexts.

Knewton Chapter 1: SI Units for Temperature and Time

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Questions and Answers

What is the SI unit of temperature?

What is the freezing point of water in kelvin?

What is the boiling point of water in kelvin?

The Celsius scale is part of the SI system.

How do you convert Celsius to Fahrenheit?

How do you convert Fahrenheit to Celsius?

What is the SI base unit of time?

What does scientific notation consist of?

What is the formula for force in terms of Newtons?

Match the following base units with their respective physical quantities:

What is the definition of volume?

What is the SI unit for mass?

What is specific gravity?

What is the definition of density?

What are the conversion factors for kilo, mega, and giga?

What is the modern definition of a kilogram?

What is the current definition of a meter?