 Welcome to Fahrenheit and Celsius Temperature Scales. Most industrial applications in the United States use the Fahrenheit and Celsius scales for temperature measurements. Each scale has useful reference points to indicate the temperature at which water freezes or boils. Let's review the Fahrenheit scale first. Gabriel Fahrenheit, a German physicist, developed the first temperature scale in the early 1700s. At sea level, water freezes at 32 degrees and boils at 212 degrees. Next, let's review the Celsius scale. With the objective of developing a temperature scale that ranges from 0 to 100 degrees between freezing and boiling, Swedish astronomer Anders Celsius developed the Celsius scale. At sea level, water freezes at 0 degrees and boils at 100 degrees. This illustration shows the freezing point and the boiling point of water on both temperature scales. Using this differential, formulas have been developed to convert between the two scales. To determine the Celsius temperature when a Fahrenheit temperature is given, use this formula. Let's look at an example. Convert 65 degrees Fahrenheit to Celsius. To determine the Fahrenheit temperature when a Celsius temperature is given, use the following formula. Let's look at an example. Convert 10 degrees Celsius to Fahrenheit. Next, we'll review a few applications of these conversions. These temperature scales are used in the measurement of heat. Heat is thermal energy that has the ability to perform work. Thermal energy is rated in work units of calories and BTUs, or British thermal units. The calorie is a unit of measurement based on the metric unit for weight in grams and the Celsius temperature scale. One calorie is the heat required to raise the temperature of one gram of water one degree Celsius. The BTU is a unit of measurement based on the customary unit for weight, pounds in the United States, and Fahrenheit temperature scale. One BTU is the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit. Now we're going to work through a few examples. Hit the pause button if you need time to figure out your answer. Question 1. The freezing temperature of water at sea level using the Celsius scale is 0 degrees. Question 2. The difference in temperature between the freezing and the boiling points of water at sea level for the Fahrenheit scale is 180 degrees. Question 3. The temperature of 15 degrees Celsius is 59 degrees Fahrenheit. Question 4. The temperature of 89 degrees Fahrenheit is 31.7 degrees Celsius. Question 5. How many calories of heat are required to raise the temperature of two grams of water five degrees Celsius? The answer is 10 calories. Two grams multiplied by five degrees Celsius equals 10 calories. Congratulations! You have completed Fahrenheit and Celsius temperature scales.