How do salt crystals form? In this experiment you will see how crystals grow and how they differ in shape.

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1 4.6 (page 1) Science Projects For ALL Students Crystals How do salt crystals form? In this experiment you will see how crystals grow and how they differ in shape. Most solids are made up of small particles. These particles have a regular pattern of sides and angles. The pattern repeats itself many times to form the solid. These small particles with a fixed shape are called crystals. Crystals for each kind of solid substance always have the same shape. crystal Words to Know Safety Precautions Adult supervision required. Please click on the whistle to view the safety guidelines. Do not drink or eat any of the substances or solutions. Dispose of all solutions by pouring them down the sink or flushing them down the toilet. Make sure the water is not above 105 F. Keep the compounds away from your eyes. Wash your hands carefully after the experiment Facts On File, Inc. Published by Facts On File, Inc.

2 Science Projects For ALL Students 4.6 (page 2) WHAT YOU NEED 2 8 ounce widemouth jars 4 address labels or Post-its pen or marker hot tap water measuring cup tablespoon table salt Epsom salt WHAT YOU NEED 2 cotton swabs 2 pieces black construction paper magnifying glass 1 foot cotton string scissors tape 2 pencils* * see Hints WHAT YOU DO PART A 1. Label one jar TABLE SALT. Label the other jar EPSOM SALT. 2. Pour 6 ounces of hot tap water in each jar. 3. Dissolve 3 tablespoons of table salt in the jar labeled table salt. 4. Dip a cotton swab into the table salt solution. Wipe it on a piece of black construction paper. 5. Let the paper dry. Examine the streak of table salt with the magnifying glass. 6. Repeat steps 3 through 5 with the Epsom salt. PART B 1. Cut the cotton string in half. 2. Tape a piece of string to the center of each of the 2 pencils Facts On File, Inc. Published by Facts On File, Inc.

3 4.6 (page 3) Science Projects For ALL Students 3. Wet each string with water. 4. Place a pencil across the mouth of the jar marked table salt so the string hangs down. Make sure the string does not touch the bottom. 5. Repeat step 4 with the jar marked Epsom salt. 6. After 4 days, observe the crystals. Draw what you see in the data table. Describe what you see in the data table Facts On File, Inc. Published by Facts On File, Inc.

4 Science Projects For ALL Students 4.6 (page 4) 7. Examine the crystals with the magnifying glass. Draw and describe what you see. OBSERVATIONS 1. Were all the salt crystals the same SHAPE? Were all the Epsom salt crystals the same SHAPE? 2. Is there a difference in color between the 2 kinds of crystals? 3. Were all the salt crystals the same SIZE? Were all the Epsom salt crystals the same SIZE? OUR FINDINGS Click on the above link to see what we found Facts On File, Inc. Published by Facts On File, Inc.

5 4.6 (page 5) Science Projects For ALL Students Salt Epsom Salts CRYSTAL DATA TABLE Eyes Only Under Microscope Diagram Description Diagram Description 1998 Facts On File, Inc. Published by Facts On File, Inc.

6 Our Findings 4. PHYSICAL SCIENCES 4.6 CRYSTALS 1. Yes. The salt crystals were cubic. The Epsom salt crystals looked like needles. 2. No. Both kinds of crystals were clear or white. 3. No. The sizes for each varied. Different sizes resulted from different rates of evaporation. The slower the rate of evaporation, the larger the crystal.

7 Science Projects For ALL Students SAFETY GUIDELINES Special Safety Note To Experimenters Some activities in this book have special safety rules to follow. The special rules are on the page with that activity. But even if every safety rule in the world is included with an experiment, you have to know how to be safe when doing it. So it s very important that you read, copy, and follow the Everyday Safety Rules that follow. Sometimes science experiments can be dangerous. Things can spill, break, or even catch fire. You have to know what to do... fast. So be prepared. Read the directions for each experiment carefully, and follow any special safety rules listed with it, then be careful. Always follow common-sense safety rules like NEVER RUN WITH SCISSORS IN YOUR HAND or BE CAREFUL WITH HOT THINGS! You already know a lot of common-sense safety rules... so remember to follow them, and have fun! Everyday Safety Rules PREPARE Clear off your work space. Read all directions. Know what problems might happen, and be prepared. PROTECT YOURSELF Follow directions step-by-step. Do just one experiment at a time. Locate exits, fire extinguisher, eye wash, and first-aid kit before you start. Ask an adult to show you how to use a fire extinguisher. Be sure there s fresh air in the room. Wear an apron and safety goggles. Don t wear contact lenses, have bare feet, or wear very loose clothing. Keep work space and floor clean. Clean up spills immediately, 1998 Facts On File, Inc. Published by Facts On File, Inc.

8 Science Projects For ALL Students Don t drink or eat around the experiment work space. Don t eat or drink any stuff tested, unless a grown-up says it s OK. USE EQUIPMENT CAREFULLY Don t set up equipment too near the edge of your work space. Be cautious when using pointed or sharp instruments, like scissors, screwdrivers, or knives. Unplug any electric device by pulling out the plug, not pulling on the cord. Use only low-voltage batteries, like those used in flashlights or smaller. Be careful when using chairs or step-stools. USING CHEMICALS Have an adult help you with all experiments requiring chemicals. Don t inhale or taste chemicals. Read all labels carefully. Label all chemicals. Wear goggles, apron, and gloves so chemicals don t touch your skin. Wash hands before and after using solutions. Wipe up spills thoroughly. HEATING THINGS Wear goggles, apron, and gloves when boiling water. Use safety tongs and heat-resistant mitten or hot pads. Never leave heated things unattended. Turn off hot plates and oven burners when you re finished. Keep flammable things away from heat and flames. Have a fire extinguisher ready. IN THE FIELD Never go on a field trip alone: follow the Buddy System. Tell a responsible grown-up where you re going. Know the area and be aware of dangers, like poisonous plants and deep water Dress for the weather conditions Facts On File, Inc. Published by Facts On File, Inc.