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Light Fountain

June 22, 2015 By Leave a Comment

What you need:light_fountain_post
• A clear water bottle
• Duct Tape or aluminum foil and tape
• Thumb tack or push pin
• Pencil
• Flashlight
• Sink or basin

What you do:
• Remove the label from the water bottle.
• Cover half (vertically – from opening to bottom of bottle) of the water bottle using duct tape or taping on aluminum foil.
• Use the thumb tack to poke a hole through the duct tape on the bottle, about two inches from the bottom of the bottle.
• Use a pencil or similar object to enlarge the hole.
• Fill the bottle with water, keeping your thumb over the hole so the water stays in.
• In a very dark room, hold the water bottle over the sink or basin.
• Shine a flashlight through the uncovered side of the bottle toward the hole where the water is coming out.
• Watch as the stream of water forms an arc that the light follows down into the sink.
• Try making the water stream a different color by putting colored cellophane in front of the flashlight lens

N.B.: The light beam travels through the stream of water, even when the stream bends, as it does in this experiment. The light beam bounces off the walls of the water stream and follows it to the end. This is called internal reflection. The light ray inside the stream of water behaves as it would inside an optical fiber. Optical fiber works like this: you send a light beam into one end of the fiber and it comes out the other end, even when it bends, just as light travels through the stream of water in your experiment.

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Foldable Egg

April 13, 2015 By Leave a Comment

What you need:Foldable Egg
•raw egg (at room temperature)
• thumbtack
• skewer
• drinking straw
• bowl
• white vinegar
• a glass
• tongs
• baby powder (or cornstarch)

What you do:
• Hold the egg over a bowl and use a thumbtack to pierce a small hole in the pointed end and a larger hole in the other end of the egg.
• Hold the egg very gently to make sure you don’t crack it!
• Use a skewer or unfolded paperclip to carefully break up the yolk inside of the egg.
• Hold a drinking straw over the smaller hole and blow through the opposite end of the straw.
• Run a little water inside the egg and shake it out.
• Use the straw again to blow out any remaining water.
• Place the egg shell in a glass and add enough vinegar to cover the egg.
• Using your fingers or a pair of tongs, gently hold the egg under the liquid until the air escapes and most of the egg shell stays below the surface (this may take several minutes).
• Leave the egg in the vinegar for several hours until the shell begins to break down.
• When the shell has started to break away, you will see a flexible egg shaped layer inside—this is the egg membrane.
• Once the egg shell has completely dissolved, remove the membrane from the glass of vinegar.
• Rinse the membrane in water and gently squeeze it to remove the water from inside.
• Pat it dry with a paper towel.
• Continue tossing until the whole thing has inflated like a balloon.
• Once it has inflated, sprinkle a little baby powder all over the outside.
• Try to get some powder inside as well as it will prevent the sides from sticking together and help the egg inflate more easily next time.
• Set the powder-coated inflated egg on the palm of your hand and press the air out with your fingers.
• Fold the egg in half several times and pinch it slightly so it stays folded, then toss it between your hands again and watch it reinflate! This process of folding and tossing can be repeated several times until the egg membrane dries out and won’t inflate.

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Kissing Apples

November 21, 2014 By Leave a Comment

What you need:Kissing apples
• Two apples
• String

What you do:
• Attach a piece of sting to each apple.
• Have each hand hold one string so that the apples  are at nose-level, 6″ apart.
• Blow hard between the apples and watch them move!

What should happen:
• The apples will get closer  to each other.

Why does that happen:
• The air pressure is lowered as you blow between the apples (think of the air molecules as ping pong balls … they balls don’t have enough time to touch the apple surface as they zoom by).
• The air surrounding the apples that’s not really moving is now at a higher pressure, and pushes the apples together.

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Air Pressure

November 21, 2014 By Leave a Comment

What you need:Air pressure1
• An empty bottle
• Foil

What you do:
• Roll up  a pea size ball out of foil.
• Place the bottle on the edge of a table.
• Put the ball of foil inside of the bottle neck.
• Try to blow the ball into the bottle.

What should happen:
• The foil ball shoots back out towards you.

Why does it happen:Air pressure2
•The same principles that keep airplanes in the sky also apply to this  experiment. The key point is that moving air is at a lower pressure than still air. This is the Bernoulli Principle. In the case of the  bottle the air that is blown towards the mouth is deflected around the the sides of the bottle (very little moves past the ball of foil). This means that the air pressure in front of the ball is lower than behind, and so the ball flies out.
Airplane wings are specially shaped so that air travels faster over the top of the wing than over the bottom surface. Again the pressure is lower above than below and the wing is “pushed” upward by the higher pressure air – called lift. The faster the plane moves forward the bigger the lift it experiences.

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Crusoe’s Science

August 25, 2014 By Leave a Comment

Robinson science3If you got stuck on an uninhabited island like Robinson Crusoe you will need to know how to get salt for cooking and drinking water for survival.
So, here you go:

What you need:Robinson science1
• large bowl
• short glass or cup
• tape
• plastic wrap
• small rock
• pitcher of water
• salt
• long spoon for stirring

What you do:
• Make saltwater by adding salt to fresh water.
• Stir the water until the salt dissolves.
• Pour about two inches of saltwater in a large bowl.
• Take an empty glass and put it in the bowl. The top of the glass should be shorter than the top of the bowl, but higher than the saltwater.
• Put plastic wrap over the top of the bowl. You may need to use tape to make sure the seal is tight.
• Put small rock right in the center of the plastic wrap, over the empty glass. That will weigh the plastic down and help you collect the water. Now you’ve made a solar still. It’s called a still because it distills, or purifies, water.
• Leave your still outside in the sun.
• Leave it alone for a few hours, or even a whole day. The longer you leave it out, the more water you’ll collect.
• When you’re ready to check your still, take the plastic wrap off and look at the water that’s collected in the cup. Do you think it’s salty or fresh?
• Taste it.

Robinson science2

Tip: Rays from the sun heat up the salty water in the bowl. When the water gets warm, it evaporates and becomes a gas. When the gas rises and hits the plastic wrap, it turns back into water droplets. Eventually, gravity makes the water droplets roll down the plastic wrap towards the rock. Then the water droplets slide off the plastic wrap into the glass. The salt doesn’t evaporate, so it gets left behind in the bowl. Water evaporates in the same way from lakes, rivers, and oceans. The water heats up, turns into a gas, and then condenses to fall back down as rain.

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Water Density

July 16, 2014 By Leave a Comment

What you need:Water density
• Clear glass or Jumbo Test Tube
• Pipettes or droppers
• Sugar
• Measuring spoons
• Food coloring
• 4 small cups

What you do:
• Fill your cups with 1 cup of warm water and add food coloring to the water.
• Add 2 tablespoons of sugar to the 1st cup, 4 tablespoons to the 2nd cup, 6 tablespoons to the 3rd cup and 8 tablespoons to the last cup.
• Label each cup with the amount of sugar added.
• Stir the water until the sugar is dissolved.
• Start with the cup with the most sugar. Using a pipette, dropper or back of a spoon, begin adding the first layer of sugar water.
• After the first layer, things get challenging. Carefully drip the next dense layer onto the surface of the first. The best technique is to place the pipette right above the surface of the first layer and against the glass. Slowly drip the next color onto the first. This will take a lot of patience. Go slow.
• The colors will begin to mix at first and then your original color will start to show.
• Repeat with the next dense color and the least dense color until you have stacked all of the colors.

NB.: The more sugar you add to the water, the more sugar molecules will take over the space, making the water more dense. The cup containing the 5 tablespoons of sugar will be the most dense, the cup with 1 tablespoons will be least dense. That is why we layer them with the most dense liquid at the bottom and the least dense at the top.

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Apple Science

July 16, 2014 By Leave a Comment

What you need:Apple Science1
• Baking sheet or wax paper
• Labeling tape
• Pen or marker
• Tongs
• Bowl
• Knife
• Lemon juice
• Vinegar
• Water
• Salty water
• Dishsoap
• Oil
• Apple

What you do:
• Use the tape to create labels for each type of liquid you will test.
• Place your labels on the baking sheet or wax paper.
• Cut the apple into slices at least 1-cm thick.
• Set out a slice of each food item on the baking sheet or was paper under the heading “Control.”
• Fill the bowl with enough liquid to fully submerge each sample.
• Dip a slice into the liquid with tongs. Be sure to cover the whole slice! Let the extra liquid drip off before placing it under the correct label on the baking sheet or wax paper.
• Rinse out the bowl and repeat until you have made samples with each liquid.
• Record all your observations, taking note of the time.

NT.:  The food’s skin protects the inside “meat” of the fruit or vegetable from damage and debris. When a fruit or vegetable is dropped and the skin is poked or broken, the food often goes bad faster. The reason fruits and some vegetables go brown when they are cut is because the part containing the oxygen-reactive enzyme is exposed. There is then a lot of surface area for the air to come in contact with the food. For the most part, brown fruits and vegetables still taste fine, they just do not look very appetizing.

Acids prevent browning because they react with the oxygen that comes into contact with the surface of the sample. Once all the acid (or whatever else is covering the surface) has reacted with the oxygen or the acid has degraded or washed off, then the sample will start to brown again. Stronger acids, like lemon juice, can even denature the enzyme. This means that the enzyme can no longer perform its original function because of its environment.

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Metal Etching

January 29, 2014 By Leave a Comment

Metal EtchingEtching -method of engraving in which lines or textures are bitten, or etched, into a metal plate, usually copper, with acid. The image produced has a spontaneity of line that comes from drawing on the plate in the same direct way as with pen or pencil on paper. The first etchings date from the early 16th century, but the basic principle had been used earlier for the decoration of armour.

What you need:Metal etching3
• Knife
• Candle
• Sewing needle
• Iodine solution
• Dropper

What you do:
• Light a candle and drop some wax on the knife.
• Put the knife over the candle so the wax melts smoothly and cover the area needed for etching.
• Let the wax cool down.
• Using the sewing needle “etch” the knife. Try to get all the way to the metal.
• Using the dropper drop the iodine solution on the scratches you made in wax.
• Let it sit a little.
• After the iodine solution becomes pale drop a little bit more.
• Let it sit for a couple of hours.
• Wash off the wax and you’ve got yourself an engraved knife.

Note: We ran the knife through the dishwasher and the engraving was still there.

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Iodine Crystals

January 21, 2014 By Leave a Comment

ScienceToday we are going to recreate Bernard Courtois’ experiment and get iodine crystals. But since not all of us have seaweed at home and the sulfuric acid is very dangerous we are going to use something that almost all of us already have.

What you need:
• Iodine solution
• Hydrogen peroxide
• Glass container

What you do:
• Pour a little bit of iodine solution into a glass container.
• Add few drops of hydrogen peroxide.
• Mix.

What happens:iodine crystals
• After a minute or so you will see grey iodine crystals on the bottom of the glass container.

Why:
• The Hydrogen peroxide helps to convert the iodine salts to the desired form.

Note: • Don’t try to store iodine crystals in a plastic bag, as they will  slowly turn to gas and leak through the plastic.
         • Don’t let the crystals sit out too long, they sublimate rapidly and you’ll loose them.
         • Don’t drop any of the iodine crystals on your carpet because the stain will come back for years no matter how good            you clean them. 

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Naked Egg

June 17, 2013 By Leave a Comment

What you need:Naked Egg
• Vinegar (at least 16 ounces)
• Two glasses
• Raw egg

What you do:
• Carefully place the egg in a cup and fill the cup with vinegar so that the egg is completely covered.
• After a day of soaking you can carefully remove the egg from the vinegar.
• Depending on your particular egg, you may already have a naked egg. However, it will not hurt you fill a cup with fresh vinegar and soak the egg for at least one more day.
• After two days of soaking you should have a pretty cool Naked Egg.

HOW DOES IT WORK?

Let’s start with the bubbles you saw forming on the shell. The bubbles are carbon dioxide gas. Vinegar is an acid called acetic acid – CH3COOH – and white vinegar from the grocery store is usually about 5% acetic acid and 95% water. Egg shells are made up of calcium carbonate. The vinegar reacts with the calcium carbonate by breaking the chemical into its calcium and carbonate parts (in simplest terms). The calcium part floats around in the solution while the carbonate part reacts to form the carbon dioxide bubbles that you see.

Some of the vinegar will also sneak through, or permeate, the egg’s membrane and cause the egg to get a little bigger. This flow of a liquid from one solution through a semi-permeable membrane and into another less concentrated solution is called osmosis. That’s why the egg is even more delicate if you handle it. If you shake the egg, you can see the yolk sloshing around in the egg white. If the membrane breaks, the egg’s insides will spill out into the vinegar. Yes, you’ve made a pickled egg! Allowing the egg to react with the carbon dioxide in the air will cause the egg to harden again.

 

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DIY Solar Oven

April 26, 2013 By Leave a Comment

What you need:Solar oven
• Pizza box, shoe box or shipping box
• Marker
• Ruler
• Scissors
• Glue stick
• Black construction paper
• Aluminum foil
• Craft knife
• Bamboo skewer, stick or dowel
• Clear plastic (plastic wrap, plastic sheet protectors, or overhead transparency plastic)

What you need:s'mores
• Using your ruler, measure 1 inch from each side of your box.
• Put a dot on each side.
• Connect the dots.
• Cut three sides with a craft knife.
• Carefully pry open the flap. (This becomes your sun window. )
• Fold the window up along the uncut line (top of the box).
• Grab the aluminum foil and your glue stick.
• Use the shiny side of the foil.
• Glue the foil to the inside of your window.
• Smooth out as many wrinkles as possible.
• Repeat steps 1-4 on the inside of the box.
• Tape the black piece of construction paper on the inside of the box.
• Glue plastic wrap, plastic sheet protectors, or transparency plastic protectors to the underside of the lid. (Try to make the seal as airtight as possible).
• Take your homemade solar cooker outside.
• Place it in direct sunlight.
• Open the flap towards the sun.
• Add your favorite solar oven recipe to the box.
• Close the box.
• Use a bamboo skewer, stick, or dowel to prop the flap open.
• Choose an angle that reflects the most light into the solar box oven.
• Cook! Check your food every 10 minutes. This could take anywhere from 20 minutes to 2 hours depending on the solar oven recipe you chose and how warm and sunny it is outside.

 

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Cool Science

March 12, 2013 By Leave a Comment

What you need:Cool Science
• Plastic bottle
• Baking sheet
• A cup
• 2 Tablespoons warm water
• 1 Teaspoon yeast
• 1/2 Cup 6% hydrogen peroxide
• 4-5 Drops food coloring
• Squirt of dish soap

What you do:
• Set a plastic bottle in the middle of a baking sheet to catch the toothpaste.
• Mix warm water and yeast in a cupand swirl together for a minute.
• Mix hydrogen peroxide, food coloring and dish soap in your  bottle.
• Pour the yeast mixture into the  bottle…and be amazed!

The reaction is summarized by this formula: 2 H2O2  –>  2 H2O + 02.
Hydrogen peroxide (H2O2) naturally breaks down into water and oxygen.  It is stored in opaque containers to help slow down this process.  Catalase (an enzyme in all living things, including yeast) speeds up the reaction.  Dish soap catches the oxygen and makes bigger bubbles and the food coloring makes it look cool.  The foam and bottle feel warm because the reaction is exothermic -it releases energy as heat.

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