Earth Materials Investigation 2

1. Earth Materials Investigation 2 Scratch Test Part 2 – Testing for Hardness

2. Science Safety • Scientists follow safety procedures to protect themselves when performing observations and experiments • They wear goggles to protect their eyes • They used the tools carefully so that they do not harm themselves or others • They do not put any scientific materials in their mouths • Spills are cleaned up quickly using the correct procedure

3. Science Jobs • Manager – this person will make sure that all members are on task • Reporter – this person will report the results of their groups work, you may need to take notes • Materials getter – this person will get materials • Materials collector – this person will return materials

4. Content Review • Rocks are made of different ingredients called minerals. • Minerals are pure materials that can’t be separated into different kinds of ingredients.

5. Vocabulary Review • weight – how heavy something is • crystal – the solid form of a material that can be identified by its special shape or pattern • property – something you can observe, such as color, shape, texture, living/non-living

6. Vocabulary Review • dissolve – to disappear in a liquid. When salt mixes with water, it goes into solution and cannot be seen until the water dries up. • earth material – a substance that comes from the earth • depth – how thick an object is from top to bottom • geologist – a person who studies the earth and the materials of which it is made.

7. Vocabulary Review • diameter – the distance across a round object • mineral – a basic earth material; a rock ingredient that cannot be broken down • evaporate – to dry up • rock – an earth material composed of different ingredients • circumference – the distance around an object

8. What We Will Learn • Some rocks can be identified by using a scratch test.

9. What We Will Do • Identify the four minerals by name. • Perform a scratch test on the four minerals we observed yesterday to determine their hardness. • First we will use the tools and practice on a piece of tile. • Then we will do the scratch test on the four minerals.

10. Materials • Material Getters will get the trays with • Their FOSS tray with their minerals • 4 pieces of chalk • 4 tiles • 4 tool kits • You will record your information in your Earth Materials Booklet. • Your work in your Earth Materials Booklet will be graded, so do your best work.

11. Procedure • You will use three tools to help determine the hardness of the minerals on the tray: • a paper clip (a geologist would generally use a pocketknife) • a penny • your fingernails • You will also use hand lenses for close observation.

12. Procedure • You will use the paper clip and some “pretend earth material” samples (chalk and tile) to learn the technique. • Try to scratch a piece of chalk and the tile with the paper clip. • Use your finger to rub away any dust or surface marks. • Use a hand lens to check for a scratch (altered surface.)

13. Discuss Chalk and Tile Results • Which is harder, chalk or tile? How do you know? • The chalk is easily scratched by the paper clip, but the tile is unscratchable. • The paper clip leaves a black mark (metal fragments) on the tile, but the mark rubs off, leaving no permanent mark.

14. Discuss Chalk and Tile Results • Which tool is harder, the paper clip or the penny? • The penny is easily scratched by the paper clip. The mark does not rub off. That is evidence that the paper clip is harder than the penny.

15. Return Materials • Return the chalk and the tiles to the materials center.

16. Quartz Clue • Quartz is the hardest of the common minerals on Earth. • Will that information help you identify the quartz sample in your set?

17. Identify the Quartz • Use your paper clip to test the four minerals. • Decide which mineral is the hardest.

18. Share • Reporters, share your group’s conclusion about which mineral they think is quartz and why they think so.

19. Gypsum Clue • Gypsum is the softest of the four minerals. • Use this clue to help you identify gypsum.

20. Share • Reporters, share your group’s conclusion about which mineral they think is gypsum and why they think so.

21. Earth Materials Booklet Page 9 • Write the names of the minerals you have identified so far. • Fill in the tool columns with a no if the tool does not scratch the mineral and yes if the tool does scratch the mineral.

22. Fluorite and Calcite Clue • Fluorite is harder than calcite. • Use your tools to identify these last two minerals. • What do you already know about these minerals from the test you have already done?

23. Identifying Fluorite and Calcite • Which scratch tool might give you the best information at this time? • The penny. • How could you find out which was harder if you didn’t have any scratch tools? • Scratch one rock against the other and find out which one has a mark left on it; that is the softer mineral.

24. Share • Reporters show us the mineral that your group has identified as calcite. • What is your evidence? • Show us the mineral that you group has identified as fluorite. • What is your evidence?

25. Seriate the Minerals’ Hardness • Tally the tools that would scratch each mineral. • Then number the minerals in order from softest to hardest. • Why did you seriate them this way?

26. Return Materials • Return materials to the Materials Center.

27. Content/Inquiry • What do we mean when we say a mineral has a certain hardness? • Hardness is a mineral property that refers to the resistance of a mineral t being scratched; minerals can be ordered by hardness. • If you did have any tools, how could you learn if one mineral was harder than another? • The harder one will always scratch the softer one.

28. Response Sheet – Scratch Test • We will go over this sheet and then you will complete it for a grade.

29. Science Stories • Read Science Stories “Digging It Up: Mining for Minerals” and “Birthstones: A Mineral for Each Month” after completing this part.