KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram.

Connector True or False? Correct the false statements 1.Heat and Temperature are the same thing. 2.Heat energy flows from somewhere hot to somewhere colder 3.Heat energy is measured in degrees celsius. 4.Hotter objects cool quicker than colder objects regardless of environment.

KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. L1 – Absolutely Freezing Lesson Outcomes KEY WORDS: heat, Thermal Energy, thermometer, joules, degree Celsius, Kelvin temperature, energy, absolute zero, Kinetic Theory. ALL: To be able to explain the difference between heat and temperature describe what is meant by absolute zero and be able to convert temperature between Celsius and Kelvin scales. MOST: To be able to describe how the temperature of a gas relates to the speed of the molecules. SOME: To be able to describe how Charle’s Law is used to find the absolute zero temperature.

KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. If you put an ice cube out in the open it melts Write a few sentences explaining why the ice cube melts. click here click here click here

KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. What is the difference between Heat and Temperature Discuss with the person next to you

KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. What is Heat? Click here Heat is a form of energy called Thermal Energy. It is measured in Joules. Heat energy always flows from warmer regions to cooler regions. HOT COLD

KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. What is Heat? Heat is a form of ______ called _______ Energy. Heat energy always flows from ________ regions to ________ regions. HOT COLD

KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. Difference between heat and temperature? What is Temperature? Temperature is a measure of how quickly molecules in an object are vibrating. It can be measured in ____ or _____ or _____. What conditions are needed for Thermal energy transfer to take place? In order for Heat Energy to flow there has to be a difference in temperature. This is because Thermal Energy always move from a warmer region to a cooler region.

KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. Why does an ice lolly melt when coming in contact with a tongue? There is a temperature difference between the tongue and the lolly, so heat energy flows from the warm tongue into the cold ice lolly. This heat transfer means that the ice lolly melts as it gets warmer, and the warm part of the tongue touching it gets cooler.

KEY WORDS: heat, thermometer, joules, degree Celsius, temperature, energy, thermogram. Watch the Demonstration and explain how it works…

If we place a balloon in liquid nitrogen it shrinks: How Volume Varies With Temperature So, gases shrink if cooled. Conversely, if we heat a gas it expands (as in a hot air balloon). Let’s take a closer look at temperature before we try to find the exact relationship of V vs. T.

No. 68  F (20  C) is not double 50  F (10  C) Yes. 44 lb (20 kg) is double 22 lb (10 kg) What’s the difference? Weights (kg or lb) have a minimum value of 0. But the smallest temperature is not 0  C. We saw that doubling P yields half the V. Yet, to investigate the effect of doubling temp- erature, we first have to know what that means. An experiment with a fixed volume of gas in a cylinder will reveal the relationship of V vs. T… Temperature scales Is 20  C twice as hot as 10  C? Is 20 kg twice as heavy as 10 kg?

Above are the results of the following experiment. Plot a graph of Temperature against Total Volume of a gas. Extend the line over to find the value at which gases occupy 0 volume!!

Temperature vs. Volume Graph (fig.7,8 pg.430) Volume (mL) Temperature (  C) – mL at 22C 31.6 mL, 23.1 mL Y=0.0847x

If a volume vs. temperature graph is plotted for gases, most lines can be interpolated so that when volume is 0 the temperature is -273  C. Naturally, gases don’t really reach a 0 volume, but the spaces between molecules approach 0. At this point all molecular movement stops. –273  C is known as “absolute zero” (no E K ) Lord Kelvin suggested that a reasonable temp- erature scale should start at a true zero value. He kept the convenient units of  C, but started at absolute zero. Thus, K =  C  C = ? K: K=  C+273 = = 335 K Notice that kelvin is represented as K not  K. The Kelvin Temperature Scale

Let’s work through that…

What is the approximate temperature for absolute zero in degrees Celsius and kelvin? Calculate the missing temperatures 0  C = _______ K100  C = _______ K 100 K = _______  C – 30  C= _______ K 300 K = _______  C 403 K = _______  C 25  C = _______ K0 K = _______  C Kelvin Practice – – 273 Absolute zero is – 273  C or 0 K

Looking back at the temperature vs. volume graph, notice that there is a direct relationship. It can be shown that V/T = constant 1.Give Charles’s law in words & as an equation. Charles’s Law: as the temperature of a gas increases, the volume increases proportionally, provided that the pressure and amount of gas remain constant, V 1 /T 1 = V 2 /T 2 Charles’s Law

2.A sample of gas occupies 3.5 L at 300 K. What volume will it occupy at 200 K? 3.If a 1 L balloon is heated from 22°C to 100°C, what will its new volume be? 4.Do questions 16, 17, 19 on page 434 V 1 = 3.5 L, T 1 = 300K, V 2 = ?, T 2 = 200K Using Charles’ law: V 1 /T 1 = V 2 /T L / 300 K = V 2 / 200 K V 2 = (3.5 L/300 K) x (200 K) = 2.3 L V 1 = 1 L, T 1 = 22°C = 295 K V 2 = ?, T 2 = 100 °C = 373 K V 1 /T 1 = V 2 /T 2, 1 L / 295 K = V 2 / 373 K V 2 = (1 L/295 K) x (373 K) = 1.26 L