Measuring Temperature Topic 2 – Heat and Temperature

Temperature In general, what do you think temperature measures?

Temperature measures how hot or cold something is.

DO YOU KNOW?! What are the two most common ways to measure temperature? Sight! & Touch!!!

Examples Sight  Glowing metal Touch  A forehead with a fever Does red mean hot? What other colors mean hot?  Mg demo Touch  A forehead with a fever

QUESTION! Are your senses always reliable???? Let’s do an experiment to test this…

Experiment – Baffle your Skin I need two volunteers (I will pick two names out of a hat to be fair) We will have: 3 bowls of water (hot, cold, and room temperature) You will place one hand in hot water and the other in cold water for ONE minute. When I tell you to, you will take your hands out and place them in the room temperature water. You will SHARE what you felt with your classmates.

Thermometers Look at the AIR thermometer and the LIQUID thermometer….. What is missing from these thermometers that we now have today? Liquid Thermometer Air Thermometer

The missing piece! The main piece missing from the thermometers was a scale. A scale is markings of numbers to indicate a precise temperature.

TELL ME…. Do you know who Anders Celsius was? What do you think he contributed to the ideas of temperature?

Anders Celsius assigned: Canada uses the Celsius scale. He used the degree as a unit of temperature. Anders Celsius assigned: 0oC to the temperature where ice melts at sea level 100oC to the temperature where water boils at sea lever

QUESTION 2: What is meant by calibration? What two fixed temperatures in Celsius are used for calibration?

Calibration Calibration means to set the starting point.

Steps to Calibration Step 1: Step 2: Step 3: Mark on the thermometer where 0oC is by putting the thermometer in an ice bath Step 2: Mark on the thermometer where 100oC is by putting the thermometer in boiling water Step 3: Divide the scale into 100 equal parts between 0oC and 100oC

Not always accurate Using Celsius’ scale is good, but not always accurate. Can you think of some reasons why??? 1. Pressure Because Alberta has low pressure (much lower than sea level), water boils below 100oC 2. Impurities in the water

TEXT BOOK TIME. Please take one of the YELLOW text books. Turn to page 194-195. (you may work with ONE partner) Read this page and answer these questions: After the creation of the Celsius scale, what new scale was developed? Why did we need this new temperature scale.

What we learned Scientists needed a temperature scale for the coldest possible temperature. This coldest temperature was called absolute zero The new temperature scale was called the Kelvin scale Absolute zero = -273.15oC