Everyone talks about the temperature, and in Maine many people complain about the temperature. But many people have probably not given much thought to what temperature means. Mostly, people talk about temperature when they talk about the weather. Will it be warm
enough to enjoy an afternoon at the beach? Is it cold enough for the rain to be freezing rain? But then again, people can ‘have a temperature’ as well. Does temperature mean the same thing when you use it to discuss someone’s state of health as when you use it to talk about the weather? Interestingly, individuals always have a temperature: sometimes it is above normal, sometimes below. We feel at our best when our temperature is in the normal range. Temperature is important for things like comfort in our homes during the hottest and coldest months of the year. It is also important for cooking and cleaning.
In this activity you will learn about the different scales used to measure temperature. You will also learn about the molecular basis for temperature. The science of chemistry draws the connection between things that are an everyday size and things that are far too small to see. By the time you complete your work here you should be able to visualize what happens when things heat up or cool off.
In the table below three temperature scales are shown. The table names each scale, shows how to write the symbol for the unit, gives information about how to convert that unit into the others, and provides a few examples of reference-point temperature. It is useful to be able to convert one temperature scale into another because different scales have different purposes. For example, the kelvin scale of temperature has no negative numbers. The lowest possible temperature is zero kelvin (0 K). This is useful for scientists who want to make measurements without concerning themselves with negative answers. Most of the world uses the standard temperature scale of Celsius so if you want to understand the weather report in Canada, you need to know what temperatures expressed in that unit mean. Fahrenheit you know all about.
|Fahrenheit||°F||(°C · 9F°/5C°) + 32||32°F water freezes
212°F water boils
|Celsius||°C||(°F -32) · 5C°/9F°||0°C water freezes
100°C water boils
|Kelvin||K||°C + 273||77 K liquid nitrogen boils
273 K water freezes
373 K water boils
How to convert Fahrenheit degrees into Celsius degrees.Convert body temperature to Celsius:
5C° (98.6 – 32)98.6°F – 32°F = 66.6°F 66.6
°F× ———— = 37.0°C 9 F°
How to convert Celsius degrees to Fahrenheit degrees.Convert the boiling point of water to Fahrenheit:
°C× ————) + 32F° = 212°F 5 C°
How to convert Celsius degrees to degrees kelvin (and the reverse).25°C + 273 = 298 K
In this section convert the temperatures to the units given in the problem.
17. Put the following temperatures in order from coldest to hottest. (worth three problems)
10K 10°C 10°F 450K 45°C 54°F 273K 25°C 25°F