Benzoic Acid Snow Globe

It's fun and easy to make your own snowglobe using water and 'snow' made from glitter or crushed egg shells, but you can use chemistry to make crystal snow that looks a lot more like the real thing. Snow is made from crystals of water. In this project, you precipitate crystals of benzoic acid, which has the advantage of not-melting at room temperature. Here's how you make the snow globe:

Snowglobe Materials

• baby food jar or ointment jar (~4 oz)
• 1 g benzoic acid
• water
• beaker or pyrex measuring cup
• hot plate or microwave or coffee maker
• stirring rod or spoon
• hot glue gun
• decoration to glue to the bottom of the snow globe, like a small plastic toy
• forceps or tweezers
• electrical tape (optional)

Make the Snow Globe

• There are a couple of ways to do this. There is my do-it-at-home method and then what you might want to do in a lab. Let's start with the lab instructions...
• In a 250 ml flask, stir 1 g benzoic acid into 75 ml of water.
• Heat the solution to dissolve the benzoic acid. You do not need to boil the water.
• Alternatively, you can measure 75 ml (5 tablespoons) of water that you heated in a microwave or coffee maker. Dissolve the benzoic acid in the hot water.
• Put down a bead of hot glue on the inside of the jar lid (or you can put it on the bottom of a clean, dry jar if you don't plan to invert the sealed jar).
• Use tweezers or forceps to position your decoration in the glue.
• While the glue is cooling, take a look at your benzoic acid solution. As it approaches room temperature, the benzoic acid will precipitate out of solution to form "snow". The rate of cooling affects the 'snow'. Slow cooling produces fine crystals. Quick cooling produces something more like snowballs than snowflakes.
• Pour the room-temperature benzoic acid solution into the glass jar.
• Fill the jar as full as possible with water. Air pockets will cause the benzoic acid to form clumps.
• Put the lid on the jar. If desired, seal the jar with hot glue or electrical tape.
• Gently shake the jar to see the pretty snow!

How the Snow Works
Benzoic acid doesn't readily dissolve in room temperature water, but if you heat the water the solubility of the molecule is increased (similar to dissolving sugar in water to make rock candy). Cooling the solution causes the benzoic acid to precipitate back into solid form. Slow cooling of the solution allows the benzoic acid to form prettier, more snow-like flakes than if you had simply mixed benzoic acid powder with water. The cooling rate of water into ice affects how real snow appears, too. Safety Tips
Benzoic acid is used as a preservative in food, so as chemicals go it is pretty safe. However, pure benzoic acid can be very irritating to skin and mucous membranes (here's an MSDS for you). Also, it can be toxic if large quantities are ingested. So... wear gloves and eye protection when preparing your solution. Excess solution can be washed down the drain (can neutralize it with baking soda first if you like). I wouldn't recommend this project for very young children. It should be fine for grade school kids with adult supervision. It's mainly intended as a fun project for teens and adults. The snow globe is not a toy -- you don't want young children taking it apart and drinking the solution.

Snow Ice Cream Recipes

There are actually a few different recipes for snow ice cream. Here are some of the most common recipes:

Snow Ice Cream without Eating Snow

This first recipe uses snow and salt to freeze the ice cream (an example of freezing point depressions), but this recipe doesn't involve actually eating the snow (the rest of the recipes do). This is a great recipe if you want to play with the snow, but don't consider it clean enough to eat.

• Fill a gallon freezer bag halfway full with snow or crushed ice.
• Add ~6 tablespoons of salt to the snow. This will lower the freezing point of the snow so you can freeze your ice cream.
• In a quart ziploc bag, mix:
  • 1/2 cup half and half
  • 1 tablespoon sugar
  • 1/2 teaspoon vanilla extract
• Zip up the quart bag, squeezing out any excees air, and put it inside the gallon bag.
• Close up the gallon bag, again removing any excess air since it makes mixing difficult.
• Wear gloves or else put a dry kitchen towel between your hands and the snow/salt bag. Squish the bags with your hands until the ice cream is frozen.
• Remove the smaller bag and enjoy your frozen treat!

Snow Ice Cream Recipe #1

This is a classic recipe that works really well because the sweetened condensed milk is thick and helps hold quickly melting snow together.

• 1 gallon or big bowl of clean snow (if you like, you can put the bowl outdoors to collect it as it falls)
• 1 14-oz can of sweetened condensed milk
• 1 tsp vanilla extract

Mix the ingredients together and eat the snow ice cream. Yummy!

Snow Ice Cream Recipe #2

• 1 gallon or big bowl full of snow
• 1 cup sugar
• 1 tsp vanilla extract
• 1 cup cream or milk

Again, just mix the ingredients together. You get the idea.

Chocolate Snow Ice Cream

• big bowl of snow
• 1 cup sugar
• 1 cup chocolate milk

Chocolate Snow Ice Cream Recipe #2

• big bowl of snow
• 1 14-oz can of sweetened condensed milk
• chocolate syrup or cocoa powder, to taste

Other Snow Ice Cream Variations

Some people like to substitute rum for the vanilla. You could add pureed fruit, such as strawberry or peaches. You may enjoy making a sort of snow ice cream float made by dropping a scoop of snow ice cream into your favorite soda. Snow ice cream does not re-freeze well, so mix the ice cream and eat it immediately. Enjoy!

Yeast & Hydrogen Peroxide Volcano

Here's how to make a safe and easy chemical volcano using two common, inexpensive household ingredients.

Difficulty: Easy

Time Required: minutes

Here's How:

1. It's incredibly easy to make this volcano. Basically, you pour the hydrogen peroxide solution (found in pharmacies and grocery stores) into a small bottle. When you are ready for the eruption, add a packet of quick rise yeast to the bottle. Stir in the yeast or swirl it around the container. Watch your 'volcano' foam and fizz!
2. If you're seeking more exact measurements, try a half cup of hydrogen peroxide with 1/2 tablespoon of yeast. If you like, you can build a model volcano shape around the bottle using clay or a paper cone.

What You Need:

• quick rising yeast
• hydrogen peroxide
• small bottle
• measuring cups (optional)
• paper or clay 'cone' (optional)

Make a Geode of Blue Copper Sulfate Crystals

Geodes are a type of rock containing crystals. Normally, millions of years are required for flowing water and minerals to deposit crystals. You can make your own 'geode' in only a few days. Grow beautiful translucent blue crystals of copper sulfate pentahydrate inside an egg shell to make your own geode.

Difficulty: Average

Time Required: 2-3 days

Here's How:

1. First, you need to prepare the eggshell. A natural geode forms inside a mineral. For this project, the mineral is the calcium carbonate of an eggshell. Carefully crack open an egg, discard the egg, and keep the shell. Clean the egg from the shell. Try for a clean break, to create two halves of the shell, or you may wish to just remove the top of the shell, for a more ball-shaped geode.
2. In a separate container, add copper sulfate to 1/4 cup of hot water. The amount of copper sulfate isn't exact. You want to stir copper sulfate into the water until no more will dissolve. More is not better! It should take a few pinches of solid material to make a saturated solution.
3. Pour the copper sulfate solution into the eggshell.
4. Place the eggshell in a location where it can remain undisturbed for 2-3 days. You may want to place the eggshell in another container to keep it from falling over.
5. Observe your geode each day. Crystals should appear by the end of the first day and will be at their best after the second or third day.
6. You can pour out the solution and allow your geode to dry after a couple of days or you can let the solution fully evaporate (week or two).

Tips:

1. Even a small increase in the temperature of the water will greatly affect the amount of copper sulfate (CuS0₄ ^. 5H₂0) that will dissolve.
2. Copper sulfate is harmful if swallowed and can irritate skin and mucous membranes. In case of contact, rinse skin with water. If swallowed, give water and call a physician.
3. Copper sulfate pentahydrate crystals contain water, so if you want to store your finished geode, keep it in a sealed container. Otherwise water will evaporate from the crystals, leaving them dull and powdery. The gray or greenish powder is the anhydrous form of copper sulfate.
4. The archaic name for copper (II) sulfate is blue vitriol.
5. Copper sulfate is used in copper plating, blood tests for anemia, in algicides and fungicides, in textile manufacturing, and as a dessicant.

Fun Crystal Growing Project

It's very easy to make a glow in the dark crystal geode. The 'rock' is a natural mineral (eggshell). You can use one of several common household chemicals to grow the crystals. The glow comes from paint, which you can get from a craft store.

Glow in the Dark Geode Materials

• eggs
• glow in the dark paint (I used GlowAway™ washable glowing paint)
• very hot water (I used my coffee maker)
• borax, alum, epsom salts, sugar, salt, or use another crystal recipe
• food coloring (optional -- I used neon green coloring)

Prepare the Glowing 'Geode'

1. There are two ways to crack your eggs. You can carefully crack the top of the egg by tapping it on a countertop. This will give you a deep geode with a smaller opening. Alternatively, you can crack the equator of the egg or carefully cut it with a knife. This will give you a geode you can open and put back together.
2. Dump the egg or make scrambled eggs or whatever.
3. Rinse out the inside of the eggshell with water. Peel away the interior membrane so you are left with only the shell.
4. Allow the egg to air dry or carefully blot it dry with a paper towel or napkin.
5. Use a paintbrush, swab, or your fingers to coat the inside of the eggshell with glowing paint.
6. Set the painted egg aside while you mix the crystal-growing solution.

Make the Crystal Solution

1. Pour hot water into a cup.
2. Stir borax or other crystal salt into the water until it stops dissolving and you see some solid at the bottom of the cup.
3. Add food coloring, if desired. Food coloring does not get incorporated into all crystals (e.g., borax crystals will be clear), but it will stain the egg shell behind the crystals, giving the geode some color.

Grow the Crystals

1. Support the shell so that it won't tip over. I made a little nest for mine in a crumpled napkin that I set inside a cereal bowl.
2. Pour the crystal solution into the shell so that it is as full as possible. Don't pour the undissolved solid into the eggshell, just the saturated liquid.
3. Set the shell somewhere where it won't get knocked over. Allow crystals to grow for several hours (overnight is shown) or as long as you like.
4. When you are satisfied with the crystal growth, pour out the solution and allow the geode to dry.
5. Phosphorescent paint is activated by exposing it to bright light. Black light (ultraviolet) produces a very bright glow, also. The duration of the glow depends on the paint you use. My geode glows for about a minute before it needs to be recharged. Some paints will produce geodes that glow for a few seconds. Other paints may glow for many minutes.
6. Store your geode in a dry location, protected from dust.

Food and Cooking Chemistry

Some of the safest and most interesting science fair projects involve the foods we eat. Food chemistry projects have the advantage of using materials that are readily available and generally non-toxic. Here are some ideas for projects. Think about ways you can explore questions related to food and cooking. Use these questions to help trigger more food chemistry ideas.

• Will chilling an onion before cutting it keep you from crying?
• If you shake up different kinds or brands of soft drinks (e.g., carbonated), will they all spew the same amount?
• Do all breakfast cereals that say they have 100% of the US RDA for iron really have the same amount? (here's the test)
• Are all potato chips equally greasy (you can crush them to get uniform samples and look at the diameter of a grease spot on brown paper)? Is greasiness different if different oils are used (e.g., peanut versus soybean)?
• Does eating breakfast have an effect on school performance?
• Do the same types of mold grow on all types of bread?
• Does increasing the ethylene concentration ripen fruit more quickly.
• Does light effect the rate at which foods spoil?
• Do foods containing preservatives really stay fresh longer than foods without them?
• How does time or season of harvest affect the chemistry and nutritional content of food?
• Does exposure to light affect the amount of vitamin C in juice?
• Can you use a household water filter to remove flavor or color from other liquids?
• Does the power of a microwave affect how well it makes popcorn?
• Can you tell/taste the difference between ground beef, chuck, and round after they have been cooked?

Do you have other food or cooking chemistry science fair project ideas that you would like to share? You can e-mail me at chemistry.guide@about.com and I will add your idea here!

Fruit Battery

If you have fruit, a couple of nails, and wire then you can generate electricity to turn on a light bulb. Learn how to make a fruit battery. It's fun, safe, and easy.

Here's What You Need

• citrus fruit (e.g., lemon, lime, orange, grapefruit)
• copper nail, screw or wire (about 2" or 5 cm long)
• zinc nail or screw or galvanized nail (about 2" or 5 cm long)
• holiday light with 2" or 5 cm leads (enough wire to connect it to the nails)

Make a Fruit Battery

1. Set the fruit on a table and gently roll it around to soften it up. You want the juice to be flowing inside the fruit without breaking its skin. Alternatively, you can squeeze the fruit with your hands.

2. Insert the zinc and copper nails into the fruit so that they are about 2" or 5 cm apart. You don't want them to be touching each other. Avoid puncturing through the end of the fruit.

3. Remove enough insulation from the leads of the light (about 1") so that you can wrap one lead around the zinc nail and one lead around the copper nail. If you like, you can use electrical tape or alligator clips to keep the wire from falling off the nails.

4. When you connect the second nail, the light will turn on!

Learn More

• Citrus fruits are acidic, which helps their juice to conduct electricity. What other fruits and vegetables might you try that would work as batteries?

• If you have a multimeter, you can measure the current produced by the battery. Compare the effectiveness of different types of fuits. See what happens as you change the distance between the nails.

• Do acidic fruits always work better? Measure the pH (acidity) of the fruit juice and compare that with the current through the wires or brightness of the light bulb.

Safe Simulated Fireworks for Kids

Fireworks are a beautiful and fun part of many celebrations, but not something you want kids to make themselves. However, even very young explorers can experiment with these safe underwater 'fireworks'.

What You Need

• water
• oil
• food coloring
• tall clear glass
• another cup or glass
• fork

Create Fireworks in a Glass

1. Fill the tall glass almost to the top with room-temperature water. Warm water is ok, too.
2. Pour a little oil into the other glass. (1-2 tablespoons)
3. Add a couple of drops of food coloring. I used one drop of blue and one drop of red, but you can use any colors.
4. Briefly stir the oil and food coloring mixture with a fork. You want to break up the food coloring drops into smaller drops, but not thoroughly mix the liquid.
5. Pour the oil and coloring mixture into the tall glass.
6. Now watch! The food coloring will slowly sink in the glass, with each droplet expanding outward as it falls, resembling fireworks falling into water.

How It Works Food coloring dissolves in water, but not in oil. When you stir the food coloring in the oil, you are breaking up the coloring droplets (though drops that come into contact with each other will merge... blue + red = purple). Oil is less dense than water, so the oil will float at the top of the glass. As the colored drops sink to the bottom of the oil, they mix with the water. The color diffuses outward as the heavier colored drop falls to the bottom.

Chemistry Projects for Bored Kids

Are you searching for something fun and educational to do that is suitable for kids? Here are some great chemistry activities and projects to get you started.

1.Make Slime

Slime is a classic chemistry project. If you are a slime connoisseur, there are actually several different versions, but this white glue and borax recipe is my own kids' favorite.

2.Crystal Spikes

This is the quickest crystal project I know, plus it's easy and inexpensive. You evaporate a solution of epsom salts on construction paper, which can give the crystals brilliant colors. The crystals develop as the paper dries, so you will get quicker results if you lay the paper out in the sun or in an area with good air circulation. Feel free to try this project using other chemicals, such as table salt, sugar, or borax.

3.Baking Soda Volcano

Part of the popularity of this project is it's easy and inexpensive. If you sculpt a cone for the volcano it can be a project that takes up a whole afternoon. If you just use a 2-liter bottle and pretend it's a cinder cone, you can have an eruption in minutes.

4. Mentos & Diet Soda Fountain

This is a backyard activity, best accompanied by a garden hose. The mentos fountain is more spectacular than a baking soda volcano. In fact, if you make the volcano and find the eruption to be disappointing, try substituting these ingredients.

5. Rock Candy

Sugar crystals do not grow overnight, so this project takes some time. However, it's a great way to learn about crystal-growing techniques and the result is edible.

6.Seven Layer Density Column

Make a density column with many liquid layers using common household liquids. This is an easy, fun and colorful science project that illustrates the concepts of density and miscibility.

7. Ice Cream in a Baggie

Learn about freezing point depression, or not. The ice cream tastes good either way. This cooking chemistry project potentially uses no dishes, so clean up can be very easy.

8.Cabbage pH Paper

Make your own pH paper test strips and then test the acidity of common household chemicals. Can you predict which chemicals are acids and which are bases?

9. Sharpie Tie Dye

Decorate a tee-shirt with 'tie dye' from a collection of pemanent Sharpie pens. This is a fun project that illustrates diffusion and chromatography plus produces wearable art.

10. Make Flubber

Flubber is made from soluble fiber and water. It's a less-sticky sort of slime that is so safe you could eat it. I'm not saying it tastes great (though you can flavor it), but it's edible. Kids will need adult supervision making this type of slime, but it's the best recipe for making a slime very young kids can play with and examine.