Exploring_temperature

Temperature
Your teacher will introduce each lesson. Where the text is blue, it indicates a link. Sometimes this gives more information. Sometimes it links to a page where a word is defined or explained. The set up activity is a traditional one: Weber's 3 bowl experiment. Place one hand in a bowl of cold water, and the other in a bowl of warm water. Now put both hands in the same bowl of room temperature water. Do you think using the hand is a sound way of assessing temperature? If not, then perhaps we need a more objective way.
 * ** Overview ** || ** Concepts ** || ** History ** || ** Philosophy ** ||
 * **Lesson 1**

Take the syringe or flask and put your finger over the end of the attached tube. Now put the flask/syringe into warm water and feel the extra pressure as the air pushes against your finger. What happens to the air particles when the flask/syringe is in the warm water?

This next activity focuses on the measurement of pressure and its change with temperature. There are two instruments we use here that early scientists used. Your teacher may use a metal pressure gauge called a [|Bourdon Gauge.]This Wikipedia page on [|pressure measurement] will also give you some background information. Do not worry if you do not understand all of it! Gas thermometer set up video Another instrument you may use is called a U-tube manometer. Your teacher will explain how to take pressure measurements. [|Home made manometer] instructions and photographs.

[|U-tube manometer explanation] of how it works (lots of maths)

[|Chemical Heritage Foundation's Gay-Lussac's and Charles' Law student worksheet] [|Gay-Lussac's paper translated from the French (Chemical Heritage Foundation)] || **Macroscopic:** The pressure increases when the air is heated, and can be felt. The use of a pressure gauge introduces an example of an instrument. A U-tube manometer can be used in place of a mechanical pressure gauge and will provide a useful introduction to simplified instrumentation.

The push of the speeding particles against an the hand is a powerful explanation here. || [|Early thermometry history]from Wikipedia Biographies: [|Guillaume] and [|Amontons] Amontons used approximate thermometers but came up with the idea of an absolute zero. [|Galileo gas thermometer]Galileo used a gas themometer [|Wikipedia on gas thermometers] [|Timeline of temperature and pressure measurement technology] [|Explanation of principles of Galileo thermoscope] [|Inventors of thermometers] || This activity links an observation with a causal explanation based on particles. Because the particles can not be seen, even with a normal microscope, they are called [|sub-microscopic]. The notion of [|cause and effect]is an important philosophical matter. || Comparison of different kinds of thermometers. The next associated lesson is on volume expansion of gases. It parallels Gay-Lussac's historical work. He noted that the thermal expansion of gases is regular and the same for all gases, but that of solids and liquids is not. We can have two activities: a flask fitted with a flexible tube, bubbling into a 100 mL measuring cylinder in a tub of water. Immersing the flask in a tub of warm water will enable the volume change to be measured. The second activity uses a balloon stretched over the mouth of a flask. the flask is placed in a tub of warm water. This activity is not quantitative and provides a good contrast with the (approximately) quantitative prior experiment. The second part focuses on expansion of liquids as a prelude to the next section. Flasks containing coloured water fitted with a stopper and glass tube can be placed into ice cold water (ice and water) and then into water at different temperatures (water baths) to calibrate. [|A home-made liquid thermometer] can be used as in this example. Thermal expansion of fluids (liquids and gases). The home made thermometer can be checked against a commercial thermometer for accuracy. || **Macroscopic:** Expansion of liquids is much smaller than for gases and different for different liquids.
 * Sub-microscopic:**
 * **Lesson 2**
 * Lesson 3**

The idea of volume change for gases is complex since there is always external air pressure to take into account, and this is not always obvious! || Biography [|Gay-Lussac], including his work on expansion of gases with temperature, and referring to the work of Charles, in French. The first paragraph of his memoir finishes with the hope that 'we are perhaps not far removed from the time when we shall be able to submit the bulk of chemical phenomena to calculation' (from Crosland MP (1978) //Gay-Lussac Scientist and Bourgeois// p 54 Cambridge University Press, Cambridge)
 * Submicroscopic:**

[|Fenby's paper Heat]t: Its Measurement from Galileo to Lavoisier is || Nature of 'discovery' i.e. who is credited (and in which culture) with the act of discovery?

Nature of measurement and primary standards. || A wider range is given by [|Wikipedia] An excellent [|history] of temperature and thermometry, written in reasonably accessible language for older teenagers. Another published history of thermometry more suitable for teachers is [|here.] Practical thermometers for measuring body temperatures are explained in the [|HowStuffWorks] site. The explanations seem suitable for older teenagers. || **Macroscopic:** Various properties, such as volume of a gas, liquid or a solid, resistance of a wire, change with changing temperature and can be used in measuring temperature. || [|Inventors] of different thermometers [|.] || The relationship between data and explanation is one to be explored here. ||
 * A lesson plan based on mercury-in-glass and glass clinical thermometers, thermocouples, resistance thermometers, bimetallic strip, and thermistors, is [|here.] The way it works is described but no indication of precision or accuracy.