How can you tell rocks on another planet apart?

Transcription

1 How can you tell rocks on another planet apart? Grade Range: K - 6 G.L.E Focus: Time Budget: 1 hour WASL Vocabulary: Overview: Students learn that scientists send rovers to other planets to learn about the different planets. They are given 4 substances that look very similar to each other (corn starch, sugar, salt, baking soda) and testing liquids (water, vinegar). They are told that these substances are rock powders ground off the rocks by a Martian rover. Students must create and run experiments to determine how the substances are the same and different. They explore questions about why people are interested in rocks on other planets. Learning Objectives: Designing experiments to test hypotheses Distinguish rocks from each other using physical characteristics. Gain knowledge about how scientists learn about other planets Sources: American Geological Institute (AGI) Materials Sedimentary rock samples depicting various environments 1 small empty cup per student To make the rock powders : Put ~2 Tbsp of a different substance in a separate cup (need 4 cups) - Flour

2 - Baking soda - Sugar - Salt Testing liquids small bottles of white vinegar (one per group) small bottles of water (one per group) Straws or some other way to mix the testing liquids with the rock powders Activity 1 handouts Flipchart or large pieces of paper to record the student s observations on Markers 1. Photocopy Activity 1 handouts Preparation 2. Fill small cups up with rock powder substances for each student. Fill up separate bottles with vinegar and water. Lesson Plan Introduction Activity A: What are Mars rovers? 1. Discuss with students why we cannot send people to Mars to explore the planet and why we must send rovers instead. Pass around pictures of rovers and discuss with your students how rovers explore a planet. What are the limitations of the rovers? How does this impact the amount or quality of data the rovers can collect? Facts about Mars rovers: Rovers weigh almost 400 lbs Rovers can move about 130 feet per Martian day (called a sol) Rovers will work and collect data for about 90 sols The average temperature on Mars is 67 C below zero and dust devils can reach 100 mph. Activity 1: How can you tell rocks on another planet apart? 1. How do Mars rovers collect information about rocks? Ask your students to brainstorm ways the rover can tell the rocks apart. Remember, it may be impossible for the rovers to bring back rocks to Earth for scientists to study, so the rover must find out as much information as possible. When a rover wants to study a rock it finds, it must expose a fresh surface on that rock. To do this, the rover uses a rock abrasion tool (RAT), which scrapes off the surface of the

3 rock and makes a rock powder. (This is like using sandpaper on a piece of wood and collecting the fine sawdust, a wood powder ) 2. Show your students the four rock powders the Mars rover has collected and tell them that they must figure out a way to tell them apart. Introduce them to the investigation question How can you tell these rocks apart? Explain they will be given two testing liquids (vinegar and water). Discuss their ideas as a class. 3. Based on your previous discussion, have students run experiments to determine how the substances are the same and different. They can use the attached Activity 1 handout to record their observations. 4. As a class, discuss the results of the student s experiments. You can record their observations on a large piece of paper. Discuss the various ways they conducted their experiments. What was successful, what didn t work? Brainstorm with your students reasons why people are interested in rocks on other planets (past environments, minerals, past life, composition of the solar system). Introduction Activity B: What do your students already know about rocks? Do this activity before discussing what Mars rovers are if your students haven t discussed or worked with rocks before. Preparation: You will need the collection of rocks (igneous, metamorphic and sedimentary) you have gathered, large pieces of paper and writing markers for recording the student s answers. Picking up, examining and collecting rocks can be the first steps in moving children toward an appreciation of geology and the bones of the Earth. Even very young children enjoy picking up rocks, lining them up, choosing favorite ones, pouring water over them to make them shiny. By letting children handle and observe rocks you give them an entry point to learning about their planet and the processes that shape the planet. Most children have seen and touched rocks, even if they have only picked up gravel from a driveway. They typically describe rocks as hard and heavy. They will know that rocks are different colors, shapes and sizes, but they may know little about the types of rocks and how these are formed. 1. Assemble the class in front of the group of rocks you have gathered. Pass the rocks around or divide them among the groups if you prefer breaking into smaller groups. 2. Discuss the questions below as a class or in smaller groups, and then have the groups share their answers with the class. What is a rock? What kinds of rocks are there? Where do rocks come from?

4 How can you tell different kinds of rocks apart? How do humans use rocks? 3. As the students are sharing their ideas, record their answers on the large pieces of paper. 4. You can extend this activity further by asking the students What they would like to learn about rocks? Record their questions. From this question you can help students realize that scientists try to find out about the world by asking questions, predicting likely answers and conducting tests to see if their ideas are correct or not. Student Assessment Activity Background Information There are three main categories of rocks, which are defined by how the rocks are formed. Sedimentary Rocks Sedimentary rocks are formed from sediment, which is solid, loose pieces of rocks (in the form of sand, silt, clay, and gravel), or the remains of living things found at the surface of the Earth. Sediment is material that has been eroded and deposited by wind, running water, waves, and ice. Sediment can also form from material left behind by the evaporation of seawater, or the settling of the remains of animals and plants in oceans, lakes, and swamps. In certain conditions, and over a very long period of time, sediment can become compacted and cemented into sedimentary rock. Sedimentary rock is often found in layers. One way to tell if a rock sample is sedimentary is to see if it is made from grains. Igneous Rocks Rocks are mixtures of one or more minerals. Just like the apples, butter, flour, and sugar are the ingredients of apple pie, minerals like quartz, mica, and feldspar are the ingredients of an igneous (from the Latin word for fire) rock called granite. Igneous rocks come from melted rock material, or magma, that lies under Earth s surface. Igneous rocks form when magma from inside the Earth moves toward the surface, or is forced above the Earth s surface as lava and ash by a volcano. Here it cools and crystallizes into rock. Metamorphic Rocks Metamorphic rocks are rocks that have become changed by intense heat or pressure while forming. In the very hot and pressured conditions deep inside the Earth s crust, both sedimentary and igneous rocks can be changed into metamorphic rock. In certain conditions these rocks cool and crystallize, usually into bands of crystals. Later they can become exposed on Earth s surface. One way to tell if a rock sample is metamorphic is to see if the crystals within it are arranged in bands.

5 Web Resources Activity Handouts

6 Activity 1: How can you tell rocks from another planet apart? Name: 1. Describe the testing liquids (color, smell, etc) Water: Vinegar: 2. Describe the four rock powders. Powder #1: Powder #2: Powder #3: Powder #4: Experiment Description Observations Can you guess what the rock powder is?

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