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Investigating Heat

Investigation 2 – Lab

Back to Investigation 2

BE PREPARED

Class materials:

1500 ml ice
3500 ml water
1 100 ml beaker
100 ml gravel
roll of aluminum foil
2 ice cube trays

Group materials:

1 liter pitcher
2 400 ml beakers
6 100 ml beakers
1 50 ml beaker
2 plastic shopping bags
3 sheets paper
2 thermometers
1 100 ml graduated cylinder
1 metal cube
1acrylic cylinder
1 brass fastener
1 woodblock
1 medium gram bear
1 glass stirring rod
2 paper towels
1 timer-stopwatch

Individual Materials:

1 Scientist Data Record

Teacher Preparation

1. Add 300 ml of ice to each of the five (5) liter pitchers and fill each liter pitcher to 1000 ml mark with water.

2. Place one pitcher of ice water at each station. NOTE: Remove any remaining ice from the pitchers before beginning Trial 1.

3. Fill one (1) 100 ml beaker with100 ml of gravel.

4. Tear fifteen (15) 10 cm strips of aluminum foil and crumple into tight balls.

5. Tear fifteen (15) 50 cm strips of aluminum foil.

6. Collect remaining materials at the distribution point.

7. Divide students into five cooperative groups.

Instruction

Direct each student group to obtain the following necessary materials from the distribution point: two (2) 400 ml beakers, six (6) 100 ml beakers, two (2) plastic shopping bags, three (3) sheets of paper, one (1) 0.5 m sheet of aluminum foil, one (1) ball of aluminum foil, one (1) brass fastener, one (1) woodblock, one (1) medium gram bear, one (1) glass stirring rod, one (1) timer-stopwatch, two (2) thermometers, one (1) metal cube, one (1) acrylic cylinder, 20 ml gravel, and two paper towels.

GET FOCUSED

Students will learn that the ability to transfer heat is a property of matter and that materials differ in their ability to transfer heat.
Materials that transfer heat easily are called conductors. Materials that are poor conductors of heat are called insulators.
As students perform their lab experiments, they should keep the following question in mind:

How do materials differ in their ability to transfer heat?

INVESTIGATE

Trial 1

Trial 1 introduces students to the concept that the ability to transfer heat is a property of matter, and that materials differ in their ability to transfer heat. Materials that transfer heat easily are called conductors. Materials that are poor conductors of heat are called insulators. In this Trial, students will determine whether a metal cube and an acrylic cylinder are conductors or insulators of heat and will use their results as a way of understanding what is meant by a conductor and insulator with regards to heat.

Students will place a metal cube and an acrylic cylinder in separate beakers of ice water. After a period of time has elapsed, students will retrieve the cube and the cylinder from the ice water and feel each item. Through touch, students will discover that the temperature of the metal cube approximates that of the ice water, while the temperature of the acrylic cylinder has not changed appreciably from its pre-immersion state. This occurs because the heat of the metal cube is transferred to the ice water surrounding it.

As plastic is a poor conductor of heat, the acrylic cylinder does not readily transfer its heat to the surrounding ice water and thus remains warm compared to the metal cube.

One of the goals of this trial is to provide students with a concrete example of how easy and poor conduction of heat feel so that they can apply the terms conductor and insulator to situations and objects they may have already encountered or will encounter in their own lives. This Trial answers the question: How do materials differ in their ability to transfer heat?

Trial 2

Trial 2 builds on the knowledge of insulators and conductors that students gained in Trial 1. This Trial encourages students to make predictions and draw conclusions about differences in the ability of different materials to conduct heat. By the end of the Trial, students should conclude that objects made of metal, stone, or glass are better conductors of heat than objects made of wood or plastic. This Trial answers the question: Which materials are conductors and insulators of heat?

Trial 3

In Trial 3, students will further explore the concepts of heat conduction and insulation introduced by Trials 1 and 2. In this trial, students will construct a thermos from a beaker and a selection of materials. Commercially constructed thermoses are containers designed to maintain a steady temperature of their contents by surrounding an inner liner with an outer container, and separating the two containers with either a vacuum or with insulating materials. In this trial, students will be provided with a beaker and a selection of materials and asked to create a thermos capable of maintaining the temperature of ice water.

Students will rely on the knowledge gained from Trials 1 and 2 to evaluate the materials available to them and decide which would serve as more effective insulators for the beaker. After designing their thermos, students will test their design by comparing the beginning and ending temperatures of ice water in the thermos. Students will compare the temperature change of the ice water in the thermos to that of ice water in an uninsulated beaker. Students will discover that their choice and arrangement of materials determine the effectiveness of their thermos in retaining the original temperature of the water. Performing this trial assists students in answering the question: Can you determine how quickly heat is transferred to the water?

Note: In order to effectively use time, students should return all other materials to the distribution point and answer Problem 3h in their Student Data Record.