Hot Rocks in the Wildlands

Description: The Hot Rock experiment will give students a better understanding of the scientific method and put a new twist on energy absorption. Students will be asked to construct a simple hot rocks box using margarine containers and plastic wrap. After collecting the data, teachers can probe students for answers about rocks and their ability to absorb heat. This can also be an opportunity for students to classify rocks according to distinguishing qualities.

Grade Levels: This lab is designed for the 5th - 7th Grade (Note: This experiment can be simplified or made more challenging depending on the developmental levels of your students. See Teacher Information.)

Approximate Time Involved: This project can run for one or several days. Students will need about thirty to forty minutes to set up their hot rock boxes and locate them on the playground. They will need about ten minutes each hour for four hours to go out and read their thermometers.

National Science Standards Addressed:

Content Standard A: As a result of activities in grades K-12, all students should develop

Abilities necessary to do scientific inquiry
Understanding about scientific inquiry

Program Standard D: The K-12 science program must give students access to appropriate and sufficient resources, including quality teachers, time, materials, and equipment, adequate and safe space, and the community.

Good science programs require access to the world beyond the classroom.

Teacher Information:

Teachers might want to obtain a large sample of different colors of rocks depending on what is being studied. Local landscape architecture businesses now offer a wide variety of decorative rock at reasonable prices. You should be able to find different colored igneous, metamorphic and sedimentary rocks at these places, and you may even get a reduced price by telling them it is for a school project. It is important that you keep your samples together and the same for the entire experiment. All of your samples will need to be fairly large because students will be using these to cover the bottom of a flex tank or margarine container. Depending on your grade level you may want to have the students classify the rocks, or you may give them this information.

After your students have mastered the cookbook experiment, a redesigned experiment can become a team exercise where your student groups might each develop and write a hypothesis, list the materials they would use, the number of each item, and a procedure. An excellent way to assess this activity is to have the teams repeat each other's experiment to see if they achieve the same results. This will also replicate the real world challenges facing a research scientist.

Challenging Your Students to Be Problem Solvers:

To make this experiment more challenging to your students, you might just want to pose a question such as: What rock color will absorb the most heat? Does being igneous, metamorphic or sedimentary increase the amount of heat a rock will absorb over a given time? What location in the will produce the best results for an experiment of this nature? Design an apparatus and conduct an experiment to measure the amount of heat that can be absorbed by each of the three groups of rocks. Design and conduct an experiment that will demonstrate the environmental advantages of the heat absorption of rocks.

Needed Materials (to set up four test sites): 16 - 2 liter (1/2 gal.) plastic flex tanks (purchased from NASCO), or 16 - 3 lb. margarine containers of about the same 1/2 gal. size, or 16 - 2-liter clear plastic pop bottles with tops cut off, a role of clear plastic wrap, 4 kilograms (9 lbs.) of each of three to six different colors of rock that all have about the same density, 16 Celsius thermometers, 20 - large rubber bands.

Safety Rule: When working with any type of glassware (thermometer) take care not to break the item, it may become a hazard.

Procedure:

Student Information: The following information will provide you with the steps for setting up your hot rock boxes and for running the lab. It is important to hold all of the variables constant except for those that are being manipulated. Constant (or controlled variables) would be such things as: the size of the flex tanks or margarine containers, the amount of time the experiment is conducted, the material the containers are made of, the amount of rocks in each box, etc. Manipulated (or independent) variables would be those things that we change to see if the response will be different, such as: the color of the rocks in the hot rock boxes. The responding (or dependent) variable for this experiment will be the recorded temperature absorbed and retained by each group of rocks. The reporting form for this experiment is set up so that you can determine the types of rocks you want to put out and where you want to place your boxes. NOTE: Be sure to include a control hot rock box at each chosen site that will have no rocks in it. Also remember that a good scientific experiment is repeated a minimum of three times. Therefore, your data will be more accurate if you set up several hot rock boxes that are exactly the same and then compile an average of your data.

Procedural Steps for Conducting the Investigation

1. NOTE: To help clarify the amount and variety of data you may want to collect, create a data table before beginning the experiment.
2. Break into four groups, or the number of groups your teacher has decided upon.
3. Each group will need four flex tanks, margarine containers or 2-liter plastic pop bottles, 1 kilogram of each of three rock colors, four thermometers, and enough plastic wrap to seal the top of each container.
4. Fill each of the three containers with 1kilogram of one rock color, or to a level of 5 cm. from the bottom. Leave the fourth container empty to act as the control.
5. On a sunny day, proceed outside and locate a flat place to conduct your experiment that will remain sunny for at least two hours.
6. Carefully place a thermometer in each container on top of the rocks so that it can be read easily. After at least two minutes, read and record the temperature of each thermometer. NOTE: It is not uncommon for thermometers to read differently so be sure to read and carefully record the temperature of each thermometer.

7. With the thermometer inside, seal the top of each container with plastic wrap using rubber bands to hold it in place. You have now created your hot rock boxes

8. At the end of one and two hours, return and record the temperatures of each thermometer while it remains inside the hot rocks boxes.
9. After you have recorded the temperatures at the end of the second hour, place the four hot rock boxes in a shaded area.
10. After an hour in the shade, record the temperatures in each of the hot rock boxes. Repeat this procedure again after two hours in the shade?
11. You may want to try this experiment again on another sunny day when the outside temperature is warmer or colder than this day. You may also want to run this test for a longer or shorter period of time to see if there is any difference in the results. Finally, you might want to try different rock groups of the same color (Example: quartz, white marble, and white sandstone). NOTE: All of these options are available on the recording form.
12. This is also an opportunity to study your rocks to determine the different characteristics that will help you classify them into one of the three major rock groups - igneous, sedimentary, or metamorphic.

Below is a list of questions that can be used to stimulate student discussions. If your students are at a developmental level where you are able to challenge their higher level thinking skills, then only present them with the first set of questions from each group below. Use the second list of questions as a way to stimulate thinking when your students seem unable to expand their knowledge on their own.

Examining Results

Discussion Questions that Require More Critical Thinking Skills:

What were your conclusions for this experiment?
What could you infer based on your conclusions?
How would you design this experiment differently the next time?

Discussion Questions that Require Less Critical Thinking Skills

Which color of rock absorbed the most heat and retained it for the longest period of time?
How would you go about testing your rocks to see if the rock group (igneous, metamorphic. or sedimentary) made a difference in their abilities to absorb heat?
Did the box without rocks have a temperature increase or decrease? Why or why not?
Where did the biggest difference in temperature between the control and the test boxes occur?
Would the time of the year influence your results (spring summer fall winter)? Why?

Rock Links

GeoMan's Mineral and Rock Identification This is another site to help you identify your rocks and minerals

GeoMan's Earth Science Websites A list of Earth Science websites

Energy Efficiency and Renewable Energy Network/Kid's Stuff This site provides a list of pages for kids to investigate alternative forms of energy.

Ecology Communications Extensive environmental network spotlights environmental programs and offers essays, a gardening column, and links to orgs grouped by topic.