BUILD A TABLETOP HOVERCRAFT! An old CD or DVD disc A 9” balloon A pop-top cap from a liquid soap bottle or a water bottle A hot glue gu 1. If you are using the cap from a water bottle, cover the center hole of the CD with a piece of tape and poke about 6 holes in the tape with a push-pin or small nail. This will slow down the flow of air and allow your hovercraft to hover longer. 2. Use the hot glue gun to glue the cap to the center of the CD or DVD disc. Create a good seal to keep air from escaping. 3. Blow up the balloon all the way and pinch the neck of it. (Don’t tie it.) 4. Make sure the pop-top is closed and fit the neck of the balloon over the pop-up portion of the cap. (This is usually easier with 2 people) 5. That’s it! When your ready to commence hovering, simply put the craft on a smooth surface and pop the top open.
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Transcript
BUILD A TABLETOP HOVERCRAFT!
An old CD or DVD disc
A 9” balloon
A pop-top cap from a liquid soap bottle or a water bottle
A hot glue gu
1. If you are using the cap from a water bottle, cover the center hole of the CD with a piece of tape and
poke about 6 holes in the tape with a push-pin or small nail. This will slow down the flow of air and
allow your hovercraft to hover longer.
2. Use the hot glue gun to glue the cap to the center of the CD or DVD disc. Create a good seal to keep
air from escaping.
3. Blow up the balloon all the way and pinch the neck of it. (Don’t tie it.)
4. Make sure the pop-top is closed and fit the neck of the balloon over the pop-up portion of the cap.
(This is usually easier with 2 people)
5. That’s it! When your ready to commence hovering, simply put the craft on a smooth surface and pop
the top open.
HAPPY HOVERING!
The air flow created by the balloon causes a cushion of moving air between the disc and the surface. This
lifts the CD and reduces the friction which allows the disc to hover freely. Large scale hovercraft are capable
of traveling over land, snow and water.
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these
questions:
1. Does the size of the balloon affect the CDs ability to hover?
2. Does a helium balloon work better than an air filled balloon?
3. Do larger discs make better hovercrafts (plastic picnic plates, old record albums) ?
The Magic Ketchup Experiment!
You can make a pack of ketchup float and sink
at your command while it's sealed inside a bottle!
* A 1 liter plastic bottle
* Ketchup pack from a fast food restaurant
* Salt (using Kosher salt helps keep the water
from becoming foggy)
1. Remove any labels from the bottle and fill it all the way to the top with water.
2. Add a ketchup pack to the bottle.
3. If the ketchup floats, you're all set - go to step 4. If the ketchup sinks in the bottle, go to step 5.
4. For the floating ketchup pack simply screw the cap on the bottle and squeeze the sides of the bottle
hard. If the ketchup sinks when you squeeze it, and floats when you release it, congratulations,
you're ready to show it off. If it does not sink when you squeeze it, try a different kind of ketchup
pack or try a mustard or soy sauce pack.
5. If the ketchup pack sinks, add about 3 tablespoons (45 ml) of salt to the bottle. Cap it and shake it
up until the salt dissolves. (Kosher salt will keep the water from getting too cloudy, although it will
usually clear up over time if using regular table salt.)
6. Continue adding salt, a few tablespoons at a time until the ketchup is just barely floating to the top
of the bottle.
7. Once it is consistently floating, make sure the bottle is filled to the top with water, and then cap it
tightly.
8. Now squeeze the bottle. The magic ketchup should sink when you squeeze the bottle and float up
when you release it. With some practice you can get it to stop in the middle of the bottle.
This experiment is all about buoyancy and density. Buoyancy describes whether objects float or sink. This
usually describes how things float in liquids, but it can also describe how things float or sink in and various
gasses.
Density deals with the amount of mass an object has. Adding salt to the water adjusted the water's density
to get the ketchup to float. Sound complicated? It is, but here's the basics on the ketchup demo...there is a
little bubble inside of the ketchup packet. As we know bubbles float, and the bubble in the ketchup
sometimes keeps the heavy packet from sinking. When you squeeze the bottle hard enough, you put
pressure on the packet. That causes the bubble to get smaller and the entire packet to become MORE
DENSE than the water around it and the packet sinks. When you release the pressure, the bubble expands,
making the packet less dense (and more buoyant) and, alas, it floats back up. This demonstration is
sometimes known as a CARTESIAN DIVER.
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these
questions:
1. Do different food packs (ketchup, mustard, soy sauce) have the same density?
2. Does the temperature of the water affect the density of the ketchup packet?
3. Does the size of the bottle affect how much you have to squeeze to get the packet to sink?
www.sciencebob.com
(The Elephant's Toothpaste Experiment)
A clean 16 ounce plastic soda bottle
1/2 cup 20-volume hydrogen peroxide liquid (20-volume is
a 6% solution, ask an adult to get this from a beauty supply
store or hair salon)
1 Tablespoon (one packet) of dry yeast
3 Tablespoons of warm water
Liquid dish washing soap
Food coloring
Small cup
Safety goggles
NOTE: As you can see from the picture, foam will overflow from
the bottle, so be sure to do this experiment on a washable surface,
or place the bottle on a tray.
1. Hydrogen peroxide can irritate skin and eyes, so put on those
safety goggles and ask an adult to carefully pour the hydrogen
peroxide into the bottle.
2. Add 8 drops of your favorite food coloring into the bottle.
3. Add about 1 tablespoon of liquid dish soap into the bottle and
swish the bottle around a bit to mix it.
4. In a separate small cup, combine the warm water and the yeast
together and mix for about 30 seconds.
5. Now the adventure starts! Pour the yeast water mixture into the
bottle (a funnel helps here) and watch the foaminess begin!
Foam is awesome! The foam you made is special because each
tiny foam bubble is filled with oxygen. The yeast acted as a
catalyst (a helper) to remove the oxygen from the hydrogen
peroxide. Since it did this very fast, it created lots and lots of
bubbles. Did you notice the bottle got warm. Your experiment
created a reaction called an Exothermic Reaction - that means it
not only created foam, it created heat! The foam produced is just
water, soap, and oxygen so you can clean it up with a sponge and
pour any extra liquid left in the bottle down the drain.
This experiment is sometimes called "Elephant's Toothpaste"
because it looks like toothpaste coming out of a tube, but don't get
the foam in your mouth!
The project above is a DEMONSTRATION. To make it a true
experiment, you can try to answer these questions:
1. Does the amount of yeast change the amount of foam
produced?
2. Does the experiment work as well if you add the dry yeast
without mixing it with water?
3. Does the size of the bottle affect the amount of foam produced?
www.sciencebob.com
One empty 35mm plastic film canister and lid. These are getting harder to find, but stores that
develop film should have some. (The white canisters work much better than the black ones do.) If
you have trouble finding canisters, you can get them HERE.
One fizzing antacid tablet (such as Alka-Seltzer - Get this from your parents)
Water
Safety goggles
1. Put on those safety goggles and head outside - no really, when this works, that film canister really flies! If
you want to try the indoor version, do not turn the canister upside down in step 5.
2. Break the antacid tablet in half.
3. Remove the lid from the film canister and put a teaspoon (5 ml) of water into the canister.
Do the next 2 steps quickly
4. Drop the tablet half into the canister and snap the cap onto the canister (make sure that it snaps on
tightly.)
5. Quickly put the canister on the ground CAP SIDE DOWN and STEP BACK at least 2 meters.
6. About 10 seconds later, you will hear a POP! and the film canister will launch into the air!
Caution: If it does not launch, wait at least 30 second before examining the canister. Usually the cap is not
on tight enough and the build up of gas leaked out.
There's nothing like a little rocket science to add some excitement to the day. When you add the water it
starts to dissolve the alka-seltzer tablet. This creates a gas call carbon dioxide. As the carbon dioxide is
being released, it creates pressure inside the film canister. The more gas that is made, the more pressure
builds up until the cap it blasted down and the rocket is blasted up. This system of thrust is how a real
rocket works whether it is in outer space or here in the earth's atmosphere. Of course, real rockets use
rocket fuel. You can experiment controlling the rocket's path by adding fins and a nose cone that you can
make out of paper. If you like this experiment, try the Exploding Lunch Bag. Be safe and have fun!
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these
questions:
1. Does water temperature affect how fast the rocket launches?
2. Does the size of the tablet piece affect how long it takes for the rocket to launch?
3. Can the flight path be controlled by adding fins or a nosecone to the canister?
4. How much water in the canister will give the highest flight?
5. How much water will give the quickest launch?
Rapid Color Changing Chemistry!
Sometimes it’s hard to tell SCIENCE from MAGIC - and this little demonstration is a great example of that. In this experiment you will watch an almost clear liquid suddenly turn dark blue in a flash. It takes a bit of preparation, and probably a trip to the pharmacy for materials, but we think it’s worth it.
IMPORTANT SAFETY INFORMATION: This experiment should only be done with the help of an adult. Iodine will stain just about anything it touches and it can be hazardous. Hydrogen peroxide can cause eye and skin irritation - safety goggles are needed throughout the experiment. Be sure your helpful adult reads the caution labels on each container.
3 clear plastic cups 4 ounces or larger A 1000 mg Vitamin C tablet from the pharmacy (you can also use two 500mg) Tincture of iodine (2%) also from the pharmacy Hydrogen peroxide (3%) yep, also from the pharmacy Liquid laundry starch (see below for alternatives) Safety goggles Measuring spoons Measuring cup An adult helper
1. Put on those safety goggles and mash the 1000 mg Vitamin C tablet by placing it into a plastic bag and crushing it with a rolling pin or the back of a large spoon. Get it into as much of a fine powder as possible. Then put all the powder in the first cup and add 2 ounces (60 ml) of warm water. Stir for at least 30 seconds. (The water may be a little cloudy) Let’s call this “LIQUID A”
2. Now put 1 teaspoon (5 ml) of your LIQUID A into a new cup and add to it: 2 oz (60 ml) of warm water and 1 teaspoon (5 ml) of the iodine. Notice the brown iodine turned clear! Let’s call this “LIQUID B.” By the way, you’re done with LIQUID A - you can put it aside.
3. In the last cup, mix 2 oz of warm water, 1 Tablespoon (15 ml) of the hydrogen peroxide and 1/2 teaspoon (2.5 ml) of the liquid starch. This is, you guessed it, “LIQUID C”
4. Okay, that was a lot of preparation, on to the fun part. Gather the friends and family and pour all of LIQUID B into LIQUID C. Then pour them back and fourth between the 2 cups a few times. Place the cup down and observe….be patient....somewhere between a few seconds and a few minutes, the liquid will suddenly turn dark blue!
This is an example of the chemical reaction know as the IODINECLOCK REACTION. It is called a clock reaction because you can change the amount if time it takes for the liquids to turn blue. (see experiments below) The chemistry of the demonstration gets a bit complicated, but basically it is a battle of chemistry between the starch which is trying to turn the iodine blue, and the Vitamin C which is keeping it from turning blue. Eventually the Vitamin C loses and, bam! - you get instant blueness.
Note: If you do not have liquid starch, you can also use 1/2 teaspoon of corn starch or potato starch. The liquids will be more cloudy and the reaction will happen a bit more slowly, but it’s still impressive.
Clean up: Carefully pour all liquids down the drain with plenty of water and wash your hands. Recycle the cups or dispose of them in the trash.
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these questions:
1. Does the temperature of the water affect how quickly the liquids turn blue?2. Does the amount of Vitamin C added (Liquid A) affect how fast the liquid turns blue?3. Does stirring the liquids more affect how fast the liquids turn blue?
THIS EXPERIMENT REQUIRES ADULT HELP
IT DEALS WITH VERY HOT LIQUIDS
BE SMART AND BE SAFE - ONLY DO THIS WITH ADULT HELP
A wooden skewer (you can also use a clean wooden chopstick)
A clothespin
1 cup of water
2-3 cups of sugar
A tall narrow glass or jar
1. Clip the wooden skewer into the clothespin so that it hangs down
inside the glass and is about 1 inch (2.5 cm) from the bottom of the
glass. (as shown)
2. Remove the skewer and clothespin and put them aside for now.
3. Get a helpful adult!
4. Pour the water into a pan and bring it to boil.
5. Pour about 1/4 cup of sugar into the boiling water, stirring until it
dissolves.
6. Keep adding more and more sugar, each time stirring it until it
dissolves, until no more will dissolve. This will take time and patience
and it will take longer for the sugar to dissolve each time.Be sure you
don't give up too soon. Once no more sugar will dissolve, remove it
from heat and allow it to cool for at least 20 minutes.
7. NOTE: While it is cooling, some peole like to dip half of the skewer in
the sugar solution and then roll it in some sugar to help jump start
the crystal growth. If you do this, be sure to let the skewer cool
completely so that sugar crystals do not fall off when you place it
back in the glass.
8. Have your friendly ADULT carefully pour the sugar solution into the jar
almost to the top. Then submerge the skewer back into the glass
making sure that it is hanging straight down the middle without
touching the sides.
9. Allow the jar to fully cool and put it someplace where it will not be
disturbed.
10. Now just wait. The sugar crystals will grow over the next 3-7 days.
Want colored rock candy? Add food coloring to your sugar water and make
sure sure that it is pretty dark in color for the best result.
When you mixed the water and sugar you made a SUPER SATURATED
SOLUTION. This means that the water could only hold the sugar if
both were very hot. As the water cools the sugar "comes out" of the
solution back into sugar crystals on your skewer. The skewer (and
sometines the glass itself) act as a "seed" that the sugar crystals start
to grow on. With some luck and patience you will have a tasty
scientific treat! Enjoy!
The Lincoln High Dive!
A Lincoln penny (or other small coin)
A piece of card stock or stiff paper
A film canister, baby food jar, or other similar size container with an mouth slightly larger than a
penny
Pencil or pen
Scissors
1. Cut the cardstock paper into a long strip about .75 inches (2 cm) wide and form it into a hoop as
shown. The paper should be stiff enough to hold the hoop shape on its own and the hoop works best
when it is between 3-4 inches (8-10 cm) across.
2. For dramatic effect, fill the film canister with water and place on a level surface.
3. Place the hoop on the film canister as shown and balance the penny on the top of the hoop.
4. Time for Lincoln's big moment! Place a pencil through the center of the hoop and in one swift motion
fling the hoop off to the side as pictured. If you do this correctly, the hoop will fly out of the way, and
the penny will fall straight down into the canister with a splash. 10 points for Lincoln!
THE SETUP THE DIVE
This is science? You betcha. Part of Newton's first laws says, in general, that an object at rest will
remain at rest unless acted upon by an outside force. The energy of your movement with the pencil
was passed on to the hoop, making it fly out of the way quickly, but the hoop moved too fast, and
there was not enough friction to affect the penny (at rest) on top of the hoop. The penny ended up
above the film canister with nothing to hold it up. It was about then that gravity took over, and pulled
the coin straight down into the waiting water. Yep, Issac Newton and Abraham Lincoln, together in
the name of science...sort of.
The project above is a DEMONSTRATION. To make it a true experiment, you can try to
answer these questions:
1. Does the size of the hoop affect the accuracy of the falling coin?
2. Does the shape of the object on the hoop affect the accuracy of the drop?
3. Is the coin affected by how fast you fling the hoop out of the way.
www.sciencebob.com
(The World's Easiest Lava Lamp)
A clean 1 liter clear soda bottle
3/4 cup of water
Vegetable Oil
Fizzing tablets (such as Alka Seltzer)
Food coloring
1. Pour the water into the bottle.
2. Use a measuring cup or funnel to slowly pour the vegetable oil into the
bottle until it's almost full. You may have to wait a few minutes for the oil
and water separate.
3. Add 10 drops of food coloring to the bottle (we like red, but any color will
look great.) The drops will pass through the oil and then mix with the water
below.
4. Break a seltzer tablet in half and drop the half tablet into the bottle.
Watch it sink to the bottom and let the blobby greatness begin!
5. To keep the effect going, just add another tablet piece. For a true lava
lamp effect, shine a flashlight through the bottom of the bottle.
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these
questions:
1. Does the number of mylar strands affect how well the orb levitates?
2. Do different materials (hair, fur, wool) build up better static charges?
3. How long does the static charge last / how can you make it last longer?
4. Do different widths of pipe affect the floating ability of the orb?
CLICK HERE to watch student-made videos of the static orb in action.
NEED TINSEL?There are a many kinds of tinsel strands out there to try out. We have discovered that most are too heavy. The brand we use in the video is BriteStar tinsel "icicles." We know it might be hard to find that exact tinsel, so we have made it available at our store. It's 95 cents (plus shipping) and you'll get 1,000 strands of tinsel! We hope that allows more people to try out this great experiment.
1. Cut a piece of yarn about 20 inches (40 cm) long.
2. Ask an adult to use the nail to carefully punch a hold in the center of
the bottom of the cup.
3. Tie one end of the yarn to the middle of the paper clip.
4. Push the other end of the yarn through the hole in the cup and pull it
through as shown in the picture.
5. Get a piece of paper towel about the size of a dollar bill, then fold it
once and get it damp in the water.
6. Now it's time to make some noise! Hold the cup firmly in one hand,
and wrap the damp paper towel around the string near the cup. While
you squeeze the string, pull down in short jerks so that the paper
towel tightly slides along the string. If all goes well - you hear a
chicken!
This is an example of how a sounding board works. The vibrations from the
string would be almost silent without the cup, but when you add the cup, it
spreads the vibrations and amplifies them (makes them louder.) Pianos
and music boxes use wood to act as a sounding board to make the
instrument louder.
The project above is a DEMONSTRATION. To make it a true experiment,
you can try to answer these questions:
1. What types of string or yarn makes the loudest sound? Which ones make
the quietest?
2. Does the size of the cup affect the volume of the sound?
3. Try materials other than a paper towel to see if it affects the volume of
the sound.
* A few old (not shiny) pennies
* 1/4 cup white vinegar
* 1 teaspoon salt
* Non-metal bowl
* Paper towels
1. Pour the vinegar into the bowl and add the salt - stir it up.
2. Put about 5 pennies into the bowl and count to 10 slowly.
3. Take out the pennies and rinse them out in some water. Admire their
shininess!
There is some pretty fancy chemistry going on in that little bowl of yours. It
turns out that vinegar is an acid, and the acid in the vinegar reacts with the
salt to remove what chemists call copper oxide which was making your
pennies dull. You're not done yet, though, lets try another experiment:
Add more pennies to the bowl for 10 seconds, but this time , don't rinse them
off. Place them on a paper towel to dry off. In time the pennies will turn
greenish-blue as a chemical called malachite forms on your pennies. But
wait, you're still not done yet.
Place one or two nuts and bolts in the vinegar and watch - they may become
COPPER in color! The vinegar removed some of the copper from the pennies,
if there is enough copper in the vinegar, the copper will become attracted by
to the metal in the nuts and bolts and they will take on a new copper color -
cool.
The project above is a DEMONSTRATION. To make it a true experiment,
you can try to answer these questions:
1. Will other acids (like lemon juice or orange juice) work as well?
2. Does this cleaning chemistry work on other coins?
3. Do other amounts of salt make a difference in the chemistry of the
experiment?
One cup of milk
4 teaspoons of white vinegar
A bowl
A strainer
Adult help
1. Ask your friendly adult to heat up the milk until it is hot, but not boiling
2. Now ask the adult to carefully pour the milk into the bowl
3. Add the vinegar to the milk and stir it up with a spoon for about a minute
4. Now the fun part, pour the milk through the strainer into the sink - careful it may be hot!
5. Left behind in the strainer is a mass of lumpy blobs.
6. When it is cool enough, you can rinse the blobs off in water while you press them together .
7. Now just mold it into a shape and it will harden in a few days. - Cool!
Plastic? In milk? Well, sort of. You made a substance called CASEIN. It's from the latin word meaning
"cheese." CasEin occurs when the protien in the milk meets the acid in the vinegar. The casein in milk does
not mix with the acid and so it forms blobs. True plastics, called poymers, are a little different. If you want to
make a true plastic and learn more about polymers, try the Homemade Slime experiment. Have fun!
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these
questions:
1. Will more vinegar make more casein?
2. Will you get the same results with low-fat milk, soy milk?
3. Do all types of vinegar work?
4. Will other acids, such as lemon juice and orange juice work?
1 balloon (round ones will work, but the longer "airship" balloons work best) 1 long piece of kite string (about 10-15 feet long) 1 plastic straw tape
1. Tie one end of the string to a chair, door knob, or other support.2. Put the other end of the string through the straw.3. Pull the string tight and tie it to another support in the room.4. Blow up the balloon (but don't tie it.) Pinch the end of the balloon and tape the balloon to
the straw as shown above. You're ready for launch.5. Let go and watch the rocket fly!
So how does it work? It's all about the air...and thrust. As the air rushes out of the balloon, it creates a forward motion called THRUST. Thrust is a pushing force created by energy. In the balloon experiment, our thrust comes from the energy of the balloon forcing the air out. Different sizes and shapes of balloon will create more or less thrust. In a real rocket, thrust is created by the force of burning rocket fuel as it blasts from the rockets engine - as the engines blast down, the rocket goes up!
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these questions:
1. Does the shape of the balloon affect how far (or fast) the rocket travels?2. Does the length of the straw affect how far (or fast) the rocket travels?3. Does the type of string affect how far (or fast) the rocket travels? (try fishing line, nylon string, cotton string, etc.)4. Does the angle of the string affect how far (or fast) the rocket travels?
* A clear drinking glass
* 1/4 cup vegetable oil
* 1 teaspoon salt
* Water
* Food coloring (optional)
1. Fill the glass about 3/4 full of water .
2. Add about 5 drops of food coloring - I like red for the lava look.
3. Slowly pour the vegetable oil into the glass. See how the oil floats on top - cool huh? It gets better.
4. Now the fun part: Sprinkle the salt on top of the oil.
5. Watch blobs of lava move up and down in your glass!
6. If you liked that, add another teaspoon of salt to keep the effect going.
So what's going on? Of course, it's not real lava but it does look a bit like a lava lamp your parents may
have had. First of all, the oil floats on top of the water because it is lighter than the water. Since the salt is
heavier than oil, it sinks down into the water and takes some oil with it, but then the salt dissolves and back
up goes the oil! Pretty cool huh?
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these
questions:
1. How long will the effect go on if you keep adding salt?
2. Do different kinds of food oil give different effects?
3. Will other substances (sand, sugar. etc.) work the same as salt?
4. Does the height or shape of the glass affect the experiment?
A large iron nail (about 3 inches) About 3 feet of THIN COATED copper wire A fresh D size battery Some paper clips or other small magnetic objects
1. Leave about 8 inches of wire loose at one end and wrap most of the rest of the wire around the nail. Try not to overlap the wires.
2. Cut the wire (if needed) so that there is about another 8 inches loose at the other end too.
3. Now remove about an inch of the plastic coating from both ends of the wire and attach the onewire to one end of a battery and the other wire to the other end of the battery. See picture below. (It is best to tape the wires to the battery - be careful though, the wire could get very hot!)
4. Now you have an ELECTROMAGNET! Put the point of the nail near a few paper clips and it should pick them up!
NOTE: Making an electromagnet uses up the battery somewhat quickly which is why the battery may get warm, so disconnect the wires when you are done exploring.
Most magnets, like the ones on many refrigerators, cannot be turned off, they are called permanent magnets. Magnets like the one you made that can be turned on and off, are called ELECTROMAGNETS. They run on electricity and are only magnetic when the electricity is flowing. The electricity flowing through the wire arranges the molecules in the nail so that they are attracted to certain metals. NEVER get the wires of the electromagnet near at household outlet! Be safe - have fun!
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these questions:
1. Does the number of times you wrap the wire around the nail affect the strength of the nail?
2. Does the thickness or length of the nail affect the electromagnets strength?
3. Does the thickness of the wire affect the power of the electromagnet?
I know, it's not exactly an experiment, but illusions are still cool.
Illusions are images that use your EYES to confuse your BRAIN
Take a look at this grid:Did you notice the small grayish dots between the black boxes. They are not part of the drawing - they were put there by your brain! Scientists call this "visual vibration." Basically it means that when you see patterns of black and white, your eye sometimes confuses the two and blends them into patterns of gray that you see here. You are seeing something that is not really there!
This elephant is missing a leg...or is it? The artist confuses his
viewer by changing they way our brain is used to seeing things.
It seems the more you look at the elephant, the more confusing it gets.
Want to see the gears move?
Look at the dot and then move your head towards the screen and away from it.
This uses visual vibrations to create a cool effect. Try moving your head
close to, and then away from the screen. The fuzzy dots appear to move.
This simple line drawing is titled, "Mother, Father, and daughter" (Fisher, 1968)
because it contains the faces of all three people in the title.How many faces can you find?
Look at the dots in the center. Which one is bigger?
Like many similar illusions, the dots are the same size...really!
It can be hard to tell because your eye uses the other dots to make a comparison.
Check out the spiral...except it is not a spiral, just circles.
Don't believe me? Use your finger to follow the fake spiral.
The tilt of the boxes fools your brain into believing it is a spiral.
Hey, this is weird. It looks as though it's moving, but it's not. The shapes confuse the eye (really the brain) into believing that they are moving.
Click here to see another amazing moving illusion!
A packet of yeast (available in the grocery store)
A small, clean, clear, plastic soda bottle (16 oz. or smaller)
1 teaspoon of sugar
Some warm water
A small balloon
1. Fill the bottle up with about one inch of warm water.
( When yeast is cold or dry the micro organisms are resting.)
2. Add all of the yeast packet and gently swirl the bottle a few seconds.
(As the yeast dissolves, it becomes active - it comes to life! Don't bother looking for movement, yeast is a
microscopic fungus organism.)
3. Add the sugar and swirl it around some more.
Like people, yeast needs energy (food) to be active, so we will give it sugar. Now the yeast is "eating!"
4. Blow up the balloon a few times to stretch it out then place the neck of the balloon over the neck of the
bottle.
5. Let the bottle sit in a warm place for about 20 minutes
If all goes well the balloon will begin to inflate!
As the yeast eats the sugar, it releases a gas called carbon dioxide. The gas fills the bottle and then fills the
balloon as more gas is created. We all know that there are "holes" in bread, but how are they made? The answer
sounds a little like the plot of a horror movie. Most breads are made using YEAST. Believe it or not, yeast is
actually living microorganisms! When bread is made, the yeast becomes spread out in flour. Each bit of yeast
makes tiny gas bubbles and that puts millions of bubbles (holes) in our bread before it gets baked. Naturalist's
note - The yeast used in this experiment are the related species and strains of Saccharomyces cervisiae. (I'm sure
you were wondering about that.) Anyway, when the bread gets baked in the oven, the yeast dies and leaves all
those bubbles (holes) in the bread. Yum.
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these questions:
1. Does room temperature affect how much gas is created by the yeast?
2. Does the size of the container affect how much gas is created?
3. What water/room temperature helps the yeast create the most gas?
4. What "yeast food" helps the yeast create the most gas? (try sugar, syrup, honey, etc.)
clean dry paper clips
tissue paper
a bowl of water
pencil with eraser
1. Fill the bowl with water
2. Try to make the paper clip float...not much luck, huh?
3. Tear a piece of tissue paper about half the size of a dollar bill
4. GENTLY drop the tissue flat onto the surface of the water
5. GENTLY place a dry paper clip flat onto the tissue (try not to touch the water or the tissue)
6. Use the eraser end of the pencil to carefully poke the tissue (not the paper clip) until the tissue sinks.
With some luck, the tissue will sink and leave the paper clip floating!
How is this possible? With a little thing we scientists call SURFACE TENSION. Basically it means that there is
a sort of skin on the surface of water where the water molecules hold on tight together. If the conditions are
right, they can hold tight enough to support your paper clip. The paperclip is not truly floating, it is being
held up by the surface tension. Many insects, such as water striders, use this "skin" to walk across the
One plastic straw from your kitchen or local fast food restaurant Scissors Lungs (don't worry you already have them)
1. Use your fingers to press on one end of the straw to flatten it - the flatter the better.
2. Cut the flattened end of the straw into a point (see below).
3. Flatten it out again real good.
4. Now take a deep breath, put the pointed end of the straw in your mouth and blow hard into the straw. If all goes well you should hear a somewhat silly sound coming from the straw. The smaller you are, the harder it may be to get a good sound - sometimes adults can get more of a sound thanks to their bigger lungs. If you still have trouble, try flattening it out some more or cutting the straw in half.
5. Don't stop there - try cutting the straw different sizes to see how the sound changes, or make another identical straw and add the pointed end of the new straw to the uncut end of the first straw (to make the first straw longer) The sound will be very different, (more like a moose call!) and you will have to blow even harder, but give it a try.
This is science? It sure is. You see all sounds come from vibrations. That little triangle that you cut in thestraw forced the two pieces of the point to VIBRATE very fast against each other when you blew through the straw. Those vibrations from your breath going through the straw created
that strange duck-like sound that you heard. Now you will never be bored again when you go to a fast food restaurant! Have fun!
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these questions:
1. Which size straw call sound the most like a duck?
2. Which length of straw is the easiest to get a sound? Which is the hardest?
3. Does the diameter of the straw affect the sound it produces?
A jar large enough to fit a chicken bone
A chicken bone - a leg or "drumstick" bone works best
Vinegar
1. Have a nice chicken dinner and save a bone. Leg bones work best.
2. Rinse off the bone in running water to remove any meat from the bone.
3. Notice how hard the bone is - gently try bending it. Like our bones, chicken bones have
a mineralcalled calcium in them to make them hard.
4.Put the bone into the jar and cover the bone with vinegar. It might be a good idea to put the lid on
the jar or cover it - let it sit for 3 days
5. After 3 days remove the bone. It should feel different. Now can rinse it off and try bending it
again. Is it really a rubber bone?
So what happened? What is so special about vinegar that it can make a hard bone squishy? Vinegar is
considered a mild acid, but it is strong enough to dissolve away the calcium in the bone. Once the calcium
is dissolved, there is nothing to keep the bone hard - all that is left is the soft bone tissue. Now you know
why your mom is always trying to get you to drink milk - the calcium in milk goes to our bones to make our
bones stronger. With some effort and you can really get the bone to bend.
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these
questions:
1. Does the length of time the bone is in vinegar affect how much the bone bends?
2. Do smaller size bones become "bendy" sooner?
3. Do different types of vinegar affect how bendy bones become ?
A clear ONE liter plastic soda bottle and cap (not the big 2 liter bottle)
A ball point pen cap that does not have holes in it
Some modeling clay ("sculpey" works too)
1. Remove any labels from your bottle so that you can watch the action.
2. Fill the bottle to the very top with water.
3. Place a small pea-size piece of modeling clay at the end of the point on the pen cap. (see drawing)
4. Slowly place the pen cap into the bottle, modeling clay end first. (some water will spill out - that's okay) It
should just barely float. If it sinks take some clay away. If it floats too much add more clay.
5. Now screw on the bottle cap nice and tight.
6. Now for the fun part. You can make the pen cap rise and fall at your command. Squeeze the bottle hard -
the pen cap sinks...stop squeezing and the pen cap rises. With a little practice, you can even get it to stop
right in the middle.
Impressive, but how does it work? This eaxperiment is all about DENSITY. When you squeeze the bottle, the
air bubble in the pen cap compresses (gets smaller) and that makes it more dense than the water around it.
When this happens, the pen sinks. When you stop squeezing, the bubble gets bigger again, the water is
forced out of the cap, and the pen cap rises.
If it doesn't work: play around with the amount of clay and be sure the bottle is filled to the very top before
putting on the cap.
Soy Sauce Diver: That's right, next time you go to your local Chinese Foodrestaurant, ask for a packet of soy
sauce (the kind they use for take out orders) Don't open it - just put it in the bottle the same way instead of
the pen cap. When you squeeze the bottle the air bubble inside the packet compresses and become more
dense. The bubble in the packet makes it rise and fall just like the pen cap. This sometimes works with
ketchup and mustard packs too. Have fun!
The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these
questions:
1. Does the size of the bottle affect how hard you have to squeeze the make the diver sink?
2. Does it matter if the bottle is not filled all the way with water?
3. Does the temperature of the water affect the density of the the diver?