Look for: identify a testable question given the water…

9.A Carry out an investigation to measure temperature inside and outside a cup system to test whether heat or cold moves through the wall of the system.

Listen for the extent to which students can do these things:

identify a testable question given the water bath setup

discuss reasonable procedures for obtaining an accurate temperature measurement

identify important control variables

explain how manipulating the temperature of the water outside the cup system affected the temperature of the water inside the system

explain how manipulating the temperature of the water inside the cup system affected the temperature of the water outside the system

conclude that heat or cold moved through the cup wall

Use this opportunity to review and reteach about planning investigations, depending on where you have seen your students’ progress and struggles. Give students an opportunity to contribute ideas to the investigation plan before offering or confirming procedures to be followed.

If students are not identifying important controls, use challenge questions, such as these:

What if I only placed 100 mL outside the cup--would that matter?

What if we don’t seal the containers--would that change our results?

What if we measure temperature with the thermometer touching the bottom of the cup or container as opposed to the middle--do we think the temperature would be the same?

If students struggle with understanding how this lab provides evidence of heat and cold moving through the cup wall, brainstorm everyday experiences of these same processes, such as feeling the cold of an iced drink or the heat from a warm cup, placing an ice pack on an injury, heating air in an oven to cook food, boiling water to cook an egg inside the shell, feeling cold when your mouth touches ice cream, and sitting in a hot bathtub. Use the related experiences as a way to establish patterns across phenomena in which we sense heat or cold moving.

• Note that students will not establish the directionality of the movement until Lessons 13 and 14, so maintaining the idea that cold moves right now is OK.
• Preview the procedures and show students the materials to be used in the test.

SAFETY PRECAUTIONS

Go over safety precautions when working with hot liquids. Review why wearing safety goggles for the entire lab is required and how you expect students to obtain and handle the hot water throughout the lab. To ensure greater safety, you should pour the hot water into small cups for each group.

Conduct the Water Bath Lab. Convene the class in a Scientists Circle and follow Part 2 on the handout. Have 4 student volunteers assist you with the temperature measurements and sealing the containers.

• Fill 2 Rubbermaid TakeAlong containers or deli container with 200 mL room-temperature water each.
• Fill 1 Rubbermaid TakeAlong containers or deli container with 200 mL cold water.
• Fill 1 Rubbermaid TakeAlong containers or deli container with 200 mL hot water.
• Fill 2 9-oz single-wall plastic cups with 200 mL cold water each.
• Fill 2 9-oz single-wall plastic cups with 200 mL hot water each.
• Place a thermometer in each of the 4 cups and each of the 4 Rubbermaid/deli containers.
• Wait the agreed-upon time (approximately 10 seconds) and then have the student volunteers read the first temperature measurement for each cup-container pair.

Pair the cups and containers to produce the following combinations and label each combination with letters a, b, c, and d:

hot cup, room-temperature container

hot cup, cold container

cold cup, room-temperature container

cold cup, hot container

• The waterline in the container should be displaced enough to align with the waterline inside the cup.
• Seal each container’s lid by twisting it tightly down.