====== 3. Feeling Cool (Conduction) ====== PROBLEM * Students investigate properties of materials and use their understanding of temperature to explain why different materials feel warmer or cooler than each-other. CURRICULUM LINK * Students observe the effects of heat moving from one object to another, eg the feeling when hands are placed on warm or cold materials * Describes everyday interactions between objects that result from contact and non-contact forces METHOD - Student scientists are divided into two groups: - One (or more) 'hot' group(s) and one (or more) 'cool' group(s). - Student scientists create two very simple two-row tables - a 'hot' table and a 'cool' table - Students scientists set up materials on a table in the playground before recess. - Dureing recess, student scientists ask other students to touch each of the materials and state which material that they think feels coldest and which they think feels warmest. - Student scientists record their results in a table: - Students scientist in the '//hot//' group record the item that people say is warmest. - Students scientist in the '//cool//' group record what material people say is coolest. - Both groups should measure the temperature of each item (using an infra-red thermometer) at the start and at the end of their experiment. The measured temperatures should be recorded in a third, separate table. For example: ^Infra-red Measured Temperature ^Plastic ^Paper ^Metal ^Wood ^ |START of experiment | | | | | |END of experiment | | | | | Scientists in the '//hot//' group ask: 'What item do you think feels WARMEST:' and enter the reply in a table ^Which of these materials ^Plastic ^Paper ^Metal ^Wood ^ ^Feels WARMEST | | | | | Scientists in the '//cool//' group ask: 'What item do you think feels WARMEST:' and enter the reply in a table - In the top row, tick the box of the item people say is COOLEST: ^Which of these materials ^Plastic ^Paper ^Metal ^Wood ^ ^Feels COOLEST | | | | | The tables can simply be created and results entered using pen and paper, and then transferred later into a Google sheet. OPTIONAL EXTENSION * Create a Google form/sheet and have students enter data in real-time using iPad or similar mobile device Students combine discuss/graph/analyse the results that they obtained. For example: Using results that you wrote down, discuss what you observed and what that might show about heat and different materials. === Table 2. INFRA-RED - Properties Of Materials Survey: === Discuss the results of your //Heat Prediction Survey// results (see example table above). EXAMPLE QUESTIONS - Does a metal ruler feel colder or warmer than a wooden ruler? - What materials do most people think feels warmer or cooler? - Can we trust that the way things feel to us will be the same to someone else? - How can we find a way to agree about the temperature of different materials? - What does 'thermal equilibrium' mean - How can you check that the concept of 'thermal equilibrium' is correct? - Can you convince others that you are correct? Some example answers: * **My results for Table 1** (above) show that most adults and students (66%) think that metal is colder than wood. * **When measured with a thermometer** the temperature of metal and wood were ... ... * This confirms the misconceptions that most people may have (as described in Video 1. above). Most people think.... * I think the reason that the metal and wood are the same temperature is because... QUESTIONS * What is 'radiation' * What kid of stuff gets 'radiated' * What things would you say 'radiate' stuff * What is 'infra-red' and how can we use it to measure temperature? DISCUSSION * Share and compare you solution and convince others that your explanation is correct. \\ === Video - Eureka - Conduction (2min) === {{ youtube>wV7gzcKegdU?640x360 |Infra-red Radiation- How it works}} * IF UNABLE TO ACCESS YOUTUBE, TRY:[[http://viewpure.com/wV7gzcKegdU|Viewpure]] ---- === EXAMPLE MISCONCEPTION-BASED ACTIVITY - HOW WE SENSE HOT AND COLD === {{ youtube>hNGJ0WHXMyE?640x360 |Misconception - How humans sense hot and cold}} * IF UNABLE TO ACCESS YOUTUBE, TRY:[[http://viewpure.com/hNGJ0WHXMyE|Viewpure]] ---- \\ === Video - Veritasium - States of Matter (2 molecules of H + 1 molecule of O) (3min) === {{ youtube>KCL8zqjXbME?640x360 |Eureka - Veritasium - States of Matter}} * IF UNABLE TO ACCESS YOUTUBE, TRY:[[http://viewpure.com/KCL8zqjXbME|Viewpure]] ---- === Video - Eureka - Dancing Molecules (in Solids) (3min) === {{ youtube>4TPV3V39PMI?640x360 |Eureka - Dancing Molecules}} * IF UNABLE TO ACCESS YOUTUBE, TRY:[[http://viewpure.com/4TPV3V39PMI|Viewpure]] * **[[https://www.youtube.com/watch?v=w_mOvnv1ns4|DANCING MOLECULES IN LIQUIDS (3min)]]** * **[[https://www.youtube.com/watch?v=M9gsOEF71bY|DANCING MOLECULES IN VAPOUR (3min)]]** ----