Transcript Mineral Lab
Minerals • What in this classroom is made from minerals? Beryllium in computers, cell phones and emeralds Chromite-chrome faucets Feldspar in the glass Lithium-electronics batteries Minerals are found in rocks, smaller sediments and dissolved in water If you find a mineral, how do you know what it is? Can you tell by looking, if this is gold or “fool’s gold”? Can you tell if it’s diamond or quartz? Focus Question • What are the minerals in your box and how do you know? • Write down your predictions in your science notebook. I predict mineral 1 is………… I predict mineral 2 is…………. I predict mineral 3 is …………. You can’t tell just by looking! You need evidence from a variety of tests to identify a mineral. These tests identify the properties of a mineral. A property is an observable characteristic of matter. Color • Describe the color. Streak • The color of the mineral in powdered form. • Turn the mineral into a powder by rubbing it against the porcelain tile. Luster • Luster is how light reflects off a mineral. It can be metallic (shiny) or non-metallic (not shiny) Metallic luster: Non-metallic luster • Can be glassy • Can be a variety of other things, dull, greasy, but we will just call them “non-metallic” Give it a try Describe the color, streak, luster and of the 8 minerals in your box. What did you notice? • • • • • • Share data for streak Share data for luster Do we agree? Was the color always the same as the streak? Anything else that you observed? Questions that came up? How a mineral breaks: cleavage or fracture? • Cleavage-When the mineral breaks it will break along parallel planes. You will see repeating patterns: How a mineral breaks • Fracture-it will irregularly break with out a definite shape Don’t break it • Look at the edges and predict whether or not your minerals have cleavage or fracture. Share data for cleavage vs. Fracture • Mineral 1, fracture mineral 2: Cleavage Mineral 3: Fracture Mineral 4: Cleavage Mineral 5: fracture Mineral 6: Cleavage Mineral 7: Cleavage Mineral 8: cleavage Hardness p. 2 of lab • Minerals are rated on a hardness scale of 1-10. 1 is the softest (talc that makes talcum powder). 10 is the hardest (diamond) • Testing tools have a hardness rating see p. 2 in lab • The harder item scratches the softer item. • REPLACE NAIL WITH PAPERCLIP IN LAB DIRECTIONS • Read p. 2 and try answering the questions. Try #1 We will go through this one step at a time. • Scratch the mineral with your fingernail. • Does it get scratched? Then it is _______than your fingernail. Give it a hardness of 2. • Does it resist getting scratched? Then it is ____________ than your fingernail. • If it is too hard to be scratched, move to the next harder tool, the copper strip or penny. • Scratch the copper strip with your mineral. If it doesn’t scratch it is 3, if it does it is greater than 3 and you will move to a harder tool, paperclip. • Does the paperclip scratch the mineral? Then the mineral is softer than the paperclip and it is between 4-5. If it resists being scratched it is harder than 5.5. Go to the glass. • If if doesn’t scratch the glass if is 5-6. If it scratches the glass it is greater than 6. • If if doesn’t leave a streak on the streak plate it is harder than 7. Let’s try together • Mineral _____together • Rest of minerals by yourself. Share materials with you partner. But, make sure you get a chance yourself! • Share results Share results • #1: 6-8; #2: 2-4; #3: 5-7; #4:1-2; #5: 5-7 #6: 2-4 #7: 5-7 #8: 1-3 • In earth science, hardness is defined as the resistance to being scratched. • Sometimes you can use minerals instead of tools. Try the bottom of p. 2 Chemical Reactions • In a chemical reaction something new such as a gas is produced. • This is different than a phase change, when you heat something up it turns to a gas. • Put Hydrochloric acid on a rock, see if gas is produced. • If you get a gas, a chemical reaction occurred. If not, no reaction. Safety rules • • • • • You must wear goggles Put your mineral in a tray with a paper towel. Use only one-two drops. Dry your minerals off with the paper towel. Member number _____ get paper towel and throw it away. • Member number _____ is in charge of goggles. • You may not take off goggles until I have collected your Hydrochloric acid. Complete the chemical tests as a group • What are your results? Can you identify your minerals? Use the mineral identification key to match your mystery mineral with the mineral that has the most similar properties. Data Analysis • We now need to analyze our results to see what they show/tell us. • On a piece of loose-leaf, answer the following questions in complete sentences. 1. Which property was most useful to ID the rocks? WHY? 2. Which property could be most misleading to the identification of a rock? WHY? Conclusion • Complete your concluding paragraph by answering the following questions: 1. What was the purpose of this laboratory experiment? 2. What properties of minerals did you use to identify the rocks? Explain them! 3. Possible errors? 4. What additional question do you have about identifying mystery rocks?