MIT BLOSSOMS - How Cold is Cold: What is Temperature?
This video lesson is part of a two-part series and introduces the concept of temperature. Temperature can be a challenging concept to convey since our perception is tied to words that are relative to our own experience, which varies quite a lot. A short activity to be performed in the classroom shows the need for a temperature scale since qualitative descriptions are not adequate. Temperatures that vary from the hottest to coldest recorded temperatures on earth are shown in advance of introducing the boiling temperatures of a number of cryogenic liquids. Required materials include three medium-sized containers, approximately one liter each, one containing hot water (greater than 50C/120F), one ice water and one with water at an intermediate temperature. If dry ice is available locally, the demos from the video can be repeated in the classroom with the proper cautions. This overall lesson should take 30 to 45 minutes to complete. The final question is how to tell from visual observation alone which cup contains hot water and which contains liquid nitrogen. The second BLOSSOMS video in this two-part series, "How Cold Is Cold: Properties of Materials", picks up at this point. While there are no prerequisites for this lesson, it should be viewed in advance of the second lesson of the series.