1 Heat and Temperature

Becky McCoy

Title: HEAT and TEMPERATURE Timing: 50 minutes Target Audience: High school Physics

Objectives: Students Will Be Able To: • Identify the three common temperature scales. • Contrast temperature and thermal energy. • Use different types of thermometers. The Teacher Will Be Able To: • Assess students’ prior knowledge of heat. • Identify student misconceptions.

Standards Assessed: Advanced Placement (AP) Physics B Competency Goal 31 • Objective 3.02: Evaluate and investigate temperature and heat

Misconception(s) Addressed: • • • • •

Confusion between temperature and the “feel” of an object. The inability to differentiate between heat and temperature. Temperature is a mixture of cold and heat. Hot means hot, not cold. Cold is the opposite of heat.

Concept Map Vocabulary: • • • • • • • •

Temperature – a measure of the average kinetic energy of the individual particles in an object. Fahrenheit scale – the temperature scale on which 32 and 212 are the temperatures at which water freezes and boils. Celsius scale – the temperature scale on which 0 and 100 are the temperatures at which water freezes and boils. Kelvin scale – the temperature scale on which zero is the temperature at which no more energy can be removed from matter. Absolute zero – the temperature at which no more energy can be removed from matter (0 K). Thermal energy – the total energy of the particles in an object. Degree – unit of measurement of temperature. Calorie – amount of heat required to raise the temperature of one gram of water one

Becky McCoy degree Celsius.

Becky McCoy

Lesson Plan Aim: Explore thermometers and scales of temperature. Physics Push-Up: Pre-unit Assessment Quiz (5 min) Students copy questions from board and answer on loose paper. To be collected as completed. The students should give gut instinct answers; no more than 5 minutes are necessary. • Define Heat. • Define temperature. • Can water and ice co-exist at the same temperature without the ice melting or the water freezing? • Can water vapor and water co-exist at the same temperature without the water vapor condensing and the water boiling? • If 1kg of aluminum and a cup of1kg water at the same temperature are placed in a hot oven, after 5 minutes will the aluminum and water have the same temperature? Explain your reasoning. • On a cold winter morning, you get out of bed and walk across your bedroom rug to the tiled floor in the bathroom. Which floor surface has a higher temperature? Why?

Teacher Talk: Temperature and Measurements (5-7min) Remind students that temperature is something we experience every day. It helps us decide what to wear and how long to spend out doors. Temperature is also important in science because it describes an attribute of a certain piece of matter. Temperature is usually measured by a thermometer and can be read in Celsius or Fahrenheit. Discuss and ask students questions on some key temperature values on the Fahrenheit and Celsius scales (freezing and boiling temperature of water, room temperature). It is worth noting to students that Kelvin is also a unit of temperature, especially if a short thermodynamics unit will follow. A transition can be made here to make the point that temperature and heat are not analogous. Heat is a transfer of energy. Therefore, we measure how much energy an object has. When we did Mechanics, we measured energy in Joules. Now that we’re measuring the energy associated with heat, we’ll be using the unit “Calorie”. Relevant Equations: • Celsius to Fahrenheit – Tfahrenheit=Tcelsius*(9/5)+32 • Fahrenheit to Celsius – Tcelsius=(Tfahrenheit-32)*(5/9) Questions to Keep In Mind: • How is temperature relevant to the students’ lives? Heat? • Do they seem to understand when I point out that heat and temperature are inherently different?

Becky McCoy • •

How do they respond when they hear there are three different units to measure temperature? Is it intimidating (will they need more time for the material to sink in) or straightforward (have they already learned this)? Do the students have enough information to complete the activities for the week? If not, what ways can I supplement their learning?

Small Group Activity: Discovering Temperature2 (15min) In small groups of 3-5, students will discover their body is not a very effective thermometer. They will measure temperatures and learn to convert from Celsius to Fahrenheit. Materials: • Fahrenheit and Celsius thermometers • 3 bowls of water (per group) – one cold, one warm, one at room temperature • Chart paper • Ice • Microwave, hot plate, Bunsen burner, or other heat source Procedure: • Students should brainstorm definitions for the vocabulary words from the concept map. Words and definitions should be written down on chart paper. • Students fill three bowls with water. One bowl is kept on the lab table to reach room temperature. Ice is added to another bowl. The third bowl is heated using a microwave, hot plate, or Bunsen burner. • Students measure the temperature of each bowl of water using the Celsius and Fahrenheit thermometers. • Each student places one hand in the bowl of cold water and one in the warm water. After a minute, students place both hands in the bowl of room temperature water. • Groups discuss what they felt and possible explanations.

Whole Group Discussion Questions to Ask: (10 min) • • • • •

What did you experience when your hands were in separate bowls? In the same bowl? Why did you feel what you did with both hands in the same bowl? How can you explain this phenomenon? What did this activity tell you about your body as a thermometer? Are there other examples from your life where you experience this?

Homework: (5 min) Students should use the conversion equations to convert each Celsius measurement to Fahrenheit and each Fahrenheit measurement to Celsius. Each measurement should also be converted to Kelvin, for practice. Students are asked to bring in a glove, coat, winter hat, scarf, etc. for the next lesson.

Becky McCoy

Exit Strategy: (5 min) Students will hand in their short heat and temperature quiz they took at the beginning of class. In addition, students are asked to complete “321 Exit cards”, listing:  3 temperature scales that they learned about today.  2 values for the freezing point and boiling points of water.  1 question they have or one thing they’re confused about regarding temperature vs. heat.

Assessment: •

Formative: o Analyze students’ responses to pre-unit assessment quiz. o Informal questions during discussion of temperature scales. o Whole Group Discussion Q&A. o 321 Exit cards.

References: 1 2

- http://www.ncpublicschools.org/curriculum/science/scos/2004/33apphysicsb - Group activity found online, written by: Sally Ferrelle, Oglethorpe Academy, Savannah, GA