Rock Tests OUTCOME: Students use a created rock to record observations, measurements, and the results of a scratch test. STATE SCIENCE STANDARDS 1.1P.1 Compare and contrast physical properties and composition of objects. 1.1E.1 Examine characteristics and physical properties of Earth In this lesson, materials. students perform a variety of tests to record SUPPLIES: alum, salt, sand, gravel, shells, flour, food coloring, hand information about lenses, bags, foil pie pans, glass jar, paper plates, tray, water, worksheet, an artificial rock. tracing paper, push pins, pennies, paper clips, hammer This can be an opportunity to practice recording PROCEDURE OVERVIEW observations and 1. OBSERVE Draw rocks from different perspectives. measurements. 2. MEASURE Measure a rock's length, height, and circumference. 3. SCRATCH Test for hardness by scratching different parts of a rock. 4. SMASH Break down a rock and sort its components. 5. SHAKE Add the rock's components to water, shake, allow to settle. Pour remaining water into a container to see crystal formation. - 1 -
TEACHER BACKGROUND Qualitative data is any information that does not involve numbers. When students record the texture, shape, or color of the invented rock, they are recording data that is subject to interpretation. Quantitative data is information that involves numbers. In this activity, students record the length, width, and circumference of the rock. This can be a challenge for round objects. Students might place the measuring tape over the top of the rock and look straight down on the rock. Placing the rock between the spines of two books and then measuring the distance between the spines is another method for measuring the length of a round object. To test for hardness, students scratch different parts of the rock to see if grooves can be created. Simple tools are suggested for this activity. Scientists would use tools like a steel knife blade, a steel file, emery sandpaper and Carborundum sandpaper. -2-
Students study the components in their rock when it is smashed by a hammer and then sorted into a pile of white powder (flour, salt, and alum), sand, gravel, and shells. Putting the materials into a container and shaking them up with water has two purposes. It shows students that the materials will create layers, and, by pouring off the liquid for evaporation, students will see the water contained salt. Magnet Test: Bringing a magnet near a rock can show if the rock contains iron. Magnetite and hematite both are attracted to magnets. Streak Test: Rubbing a rock or mineral on a piece of white tile results in a streak of color. Often the color matches the color of the rock. Sometimes, the streak eliminates the effect of an impurity or flaw in the rock to show the true color of the rock. Black hematite results in a red-brown streak. Shiny gold pyrite results in a black streak. Vinegar Test: Dripping vinegar on a rock shows if it contains calcite. Rocks with calcite will bubble. Stronger acids show more dramatic results, so a video from the teacher disk may be shown so students can see the reaction using an acid stronger than household vinegar. -3-
PROCEDURE IN DETAIL PREPARE THE FIRST TIME ONLY: Duplicate the measuring tapes (page 8). Lamination makes them last longer. Cut them apart. Place a push pin, a penny, and a paper clip in a small container for each team. RULERS PREPARE SEVERAL DAYS BEFORE THE ACTIVITY: Combine in the large, reclosable bag: 1 cup flour, 2 teaspoons alum, 1/2 cup salt, 1 cup sand, 1/8 cup gravel, 1 tablespoon shells, 3 drops each of page 8 red, blue, and yellow food coloring. Gradually add up to 1/2 cup water, mixing until you have the consistency of pie crust. Form 1 tablespoon of the mixture into an organic shape that resembles a rock. Place each rock on a tray. Turn over each day so that it air dries in three to four days. Do NOT bake the rocks in an oven or dry in a microwave oven. Heated rocks are too hard for the scratch test. Store in a reclosable bag to seal out moisture. This recipe makes enough rocks for more than 30-40 students. PROCEDURE 1. OBSERVE YOUR ROCK Give each student a rock and a worksheet (pages 9 or 15). DRAW YOUR ROCK Have them draw the top, bottom, and each side of their rock. pages 9 or 15 Write words at the bottom of the page that describe the rock. - 4 -
2. MEASURE YOUR ROCK MEASURE YOUR ROCK Review the ways to measure using a measuring tape to measure a round object. Have students measure and record their rock's circumference and its greatest length and height on their worksheet (pages 10 or 16). pages 10 or 16 Option: Use a pan balance to measure the mass of each rock. Place the rock in one pan and use large paperclips (about 1 gram each) to find the mass of the rock. 3. SCRATCH TEST Explain that scientists use a variety of materials to test for the hardness of rocks. We can t use all those different items for testing in our classroom, but we can use simple materials that help us measure hardness and compare our rock to other rocks. Hand out a container of scratch test tools to each team. Tell students to scratch the rock gently in different places with each tool so that students will know if the hardness of the rock is uniform throughout the rock. Students scratch a different part of their created rock with each different tool. Students should draw their results and describe the grooves that may be made on their worksheet (pages 11 or 17). Students can compare results with a classmate. Is the rock the same hardness consistently with each tool? -5- SCRATCH YOUR ROCK pages 11 or 17
4. SMASH TEST Place the rock in the bottom of a lunch sack. Wrap the top of the sack around the rock so that there are two layers of paper around the rock. Turn a hammer sideways and use it to smash the rock. Doing this on a carpet square or carpeted floor makes it quieter. Each student pours the contents of his or her bag onto the paper plate and sorts it into the different materials. Students should identify as many different materials as possible. SMASH YOUR ROCK They'll find white powder, shells, and rocks. Draw each component on the worksheet (pages 12, 18). pages 12, 18-6-
5. LET IT SETTLE Collect the leftover powder from each student in a small jar from the materials kit. Secure the lid carefully. Add water. Shake vigorously. Allow the contents of the container to settle. Students will see there are layers in the container. After the water clears, pour the liquid carefully into a foil pie pan. Over the next several days, depending on the humidity, salt crystals appear in the pie pan! This is what s left from the solution after the water evaporates. Option: A booklet can be used instead of worksheets (pages 13-14, 19-20). BOOKLET FOR ROCK TESTS Read about additional rock tests (pages 21-30). pages 13-14, 19-20 STUDENT ESSAY If materials are available, attempt one or more of the tests. Additional information about the tests has been included in the Teacher Background. - 7 - pages 21-30
Duplicate this page, laminate, cut apart, and use as measuring tapes for this unit. 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0 1cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Name: Draw Your Rock Draw the top of your rock: Draw the bottom of your rock: Draw one side of your rock: Draw the other side of your rock: What will help you find your rock if it is put with other rocks? - 9 -
Name: Measure Your Rock How long is your rock? How deep is your rock? What is the circumference of your rock? How did you measure a round rock? How much does your rock weigh? List the tools you used to find your answers: - 10 -
Name: Scratch Your Rock What happened when you scratched your rock with your fingernail? What happened when you scratched your rock with your paper clip? What happened when you scratched your rock with your push pin? Were the scratches the same all over the rock? Yes No - 11 -
Name: Smash Your Rock Draw your experiment, write words to describe what you see: - 12 -
Smash Your Rock Draw what you see: Describe what you see: My Rock Book
Draw Your Rock Draw the top of your rock: Draw the bottom of your rock: Draw one side of your rock: Draw the other side: What will help you find your rock if it is put with other rocks? Measure Your Rock How long is your rock? How wide is your rock? What is the circumference of your rock? How much does your rock weigh? List the tools you used to find your answers:
Nombre: Dibuja tu piedra Dibuja la parte de arriba: Dibuja la parte de abajo: Dibuja un lado de tu roca: Dibuja el otro lado: Qué te ayudará a encontrar tu roca si es puestra con otras rocas? - 15 -
Nombre: Mide tu piedra Qué tan larga es tu roca? Qué tan ancha estu roca? Cuál es la circunferencia de tu roca? Cómo mediste una roca redonda? Cuánto pesa tu roca? Haz una lista de los instrumentos que usaste para conestar las preguntas: - 16 -
Nombre: Rasguña tu piedra Qué sucedió cuando rasguñaste la piedra con tu uña? Qué sucedió cuando rasguñaste la piedra con tu sujetapapeles? Qué sucedió cuando rasguñaste la piedra con tu clavo? Fueron los rasguños iguales en toda la piedra? Si No - 17 -
Nombre: Rompe tu piedra Dibuja tu experimento. Usa palabras para describir lo que ves. - 18 -
Rompe tu piedra Dibuja tu experimento. Usa palabras para describir lo que ves. Mi Libro de piedras - 19 -
Dibuja tu piedra Dibuja la parte de arriba: Dibuja la parte de abajo: Dibuja un lado de tu roca: Dibuja el otro lado: Qué te ayudará a encontrar tu roca si es puestra con otras rocas? Mide tu piedra Qué tan larga es tu roca? Qué tan ancha estu roca? Cuál es la circunferencia de tu roca? Cuánto pesa tu roca? Haz una lista de los instrumentos que usaste para conestar las preguntas: - 20 -