At Home with Hands On!

Build an Infinity Portal Mirror

MATERIALS:

  • Shadow box picture frame
  • Mirror, the same size as the shadowbox
  • 50% Reflective Window Film
  • Rubber gloves
  • Window cleaner
  • Microfiber Towel
  • Rubber Squeegee
  • Dawn Dish soap
  • Spray Bottle
  • LED light strand
  • Superglue (if the LED strand isn’t self-adhesive)
  • Scissors
  • Measuring tape
  • Electric Drill (or razor knife)

INSTRUCTIONS:

  1. Remove the cardboard or foam back panel of the shadow box. And carefully remove the clear glass panel from the front of the shadow box picture frame.  This might require a bit of disassembly, so go ahead and grab an adult assistant to give you a helping hand!
  2. Thoroughly clean both sides of the clear glass panel using window cleaner solution and a microfiber towel.
  3. Add 5-6 drops of dish soap to an empty spray bottle.  Fill the bottle with about 20 ounces of water. Gently shake or swirl the bottle to distribute the soap into the water. (Hint:  don’t shake the bottle too hard or the soap will foam up and make it extremely difficult to spray out later!)
  4. Cut a piece of reflective window film that is two inches wider and taller than your clear glass panel. The extra film makes it a lot easier to position the film onto the glass, while any over-hanging film can just be trimmed off later.
  5. Put on rubber gloves so you won’t leave fingerprints on the glass. In a clean room (away from any pets or dust sources) lay out the cleaned glass panel and spray the entire surface with your soapy solution.
  6. Remove the backing from the reflective film, being careful that it doesn’t stick to itself!! Spray the adhesive side of the film with your soapy solution.
  7. Gently remove any air and water bubbles or creases using a soft rubber squeegee (or you could use the edge of an old gift card). It is best to start in the center of the glass and work your way outward toward the edges.
  8. Allow the film to thoroughly dry and adhere to the glass for a few hours or even overnight.
  9. While the adhesive on the film is setting, you can measure and cut the LED string. With a measuring tape, measure the inside walls of the shadow box picture frame and cut the LED string to match.  LED strings typically have markings to show where it is okay to cut them, though this is usually wherever the copper dots are crossed by a single line.
  10. Ask your adult assistant to cut a hole in the corner of the shadow box picture frame where the LED light cord can be run out from the frame.  Connect the LED strand to its power cord, following any directions that came with the product.
  11. Feed the entire length of the LED cord through the drilled hole into the shadow box, starting at the cut end of the LED strip, and stopping just before the connection point to the power cord can enter the photo frame.
  12. Beginning at the end closest to the cord connection, remove the adhesive backing a few inches at a time and stick your LED strand into place.  (If your LED strand is not self-adhesive, you can use superglue to adhere it to the inside of the shadow box.)
  13. Using scissors or a razor knife, closely trim any extra reflective window film from the edges of your partial mirror.
  14. Carefully slide the partial mirror in the front-panel position of the shadow box, with the reflective film surface facing inward toward the LED strand.
  15. Instead of replacing the padded cardboard backing of the shadow box, place the real mirror in its place, with the reflective side facing inward toward the LED strand. Close or secure any backing clips to hold the mirror in place.
  16. Place the finished infinity mirror on a flat surface. Can you see your reflection in the mirror?
  17. Dim the lights in the room and plug in your infinity mirror. What do you see now? Why do the lights appear to tunnel infinitely through the solid table? Gently lift up the infinity mirror to make sure you haven’t actually created a portal through the table!!!

HOW DOES IT WORK:

Luckily, this project doesn’t actually create a portal through space and time, but it does use a simple trick of light. With two mirrors that reflect and transmit light differently, the infinity mirror creates a series of ever-weakening illusory reflections. The mirror in the back of the infinity mirror is a full mirror that reflects, or bounces back, almost 100% of the light that strikes it. The panel at the front of the infinity mirror (with the reflective window film attached to it) can only reflect about half of the light that strikes it. The other half of light that strikes this partial mirror is transmitted, or passes through it.

When the LED lights turn on in-between the two mirrors, some of the light escapes through the front partial mirror and into your eye. The rest is bounced back off of the rear mirror, only to be halved again when it hits the partial mirror at the front.  This cycle continues over and over again seemingly to infinity;  however, because a percentage of light escapes with each and every cycle, the reflected images of the LEDs look a bit dimmer and dimmer than the one before.  Eventually, there is too little light escaping the mirror for our eyes to detect it, and the rest of the ‘infinite’ images fade to darkness.

THE MORE YOU KNOW:

Partial mirrors or “one-way mirrors” are used by police investigators to monitor suspected criminals while they are being questioned.  This half-mirrored panel actually transmits and reflects light equally in both directions.  But the unique effect comes by having different light conditions in the two rooms on either side of the mirror; one room must be much brighter than the other for the illusion to work.

With lots of light filling the interrogation room, most of the light seen in the one-way mirror on this side is reflected back from within this room, and the very small amount of light transmitted through from the dark room is drowned out.  Anyone standing in the bright room will observe a mirrored reflection.

With very little light in the dark observation room, most of the light seen in the one-way mirror is transmitted through the glass from the other room, and the very small amount of light reflected from within this room is drowned out.  Anyone standing in the dark room observes a clear window into the other room.

GOING ONE STEP FURTHER:

  1. Infinity mirrors are extremely customizable and they can be as unique as the person who builds them! You could try drawing shapes or letters with your LED strand inside of the shadow box picture frame for a more interesting reflection pattern.
  2. You could also glue non-luminous objects like seashells or small toys against the back mirror. Even though these objects don’t give off light on their own, the light that strikes them WILL create a series of reflections in the infinity mirror.
  3. Try using a very narrow or much wider shadowbox to build your infinity mirror.  If there is a larger gap between the two mirrors, will the reflected images appear further apart or closer together? Why?
  4. Experiment with different sources of light inside of your infinity mirror. Cordless lights (like small flashlights or battery-powered tea lights) produce enough light to create a cool illusion, plus they don’t require a hole being drilled in the side of the shadow box frame, so they might be a better option for your mirror!

Make your own infinity portal mirror, and let your scientific brilliance shine on and on and on and on and on and on and on… !!!

Hands on Museum - Rocket taking off, because rockets are awesome

Launch a Liquid-Fueled “Bottle Rocket”

MATERIALS:

  • Empty 12oz water bottle
  • Strong tape
  • 3 Pencils (preferably unsharpened)
  • Plastic bottle stopper or cork (NOT a screw-on cap!)
  • Measuring cups and Measuring spoons
  • Paper towels
  • Distilled white vinegar
  • Baking soda
  • Funnel
  • Adult Assistant

INSTRUCTIONS:

  1. Unscrew and discard the cap of an empty 12oz water bottle.
  2. Create a launch stand for your rocket by securely taping 3 pencils onto the side of the water bottle, making sure that they are evenly spaced. The eraser ends should point upward and rise past the bottle opening by about an inch.
  3. Using a funnel, pour 6-8 ounces of distilled white vinegar into the bottle.
  4. Place 2 Tablespoons of Baking soda in the center of a dry paper towel. Wrap the paper towel around the baking soda and then fold it up to create a bundle that is thin enough to fit through the water bottle’s opening.
  5. Now be sure to grab your adult assistant, and take your rocket assembly outside to a wide open spot!
  6. Squeeze the baking soda bundle just inside of the bottle’s neck.
  7. Push a snug-fitting bottle stopper or cork into the bottle mouth.
  8. Give the rocket a quick shake.
  9. Quickly flip the bottle upside down so it is standing upright on the three pencil erasers.
  10. Back away fast, or prepare to get splashed!
  11. Once your rocket has returned to Earth, you can re-fuel and launch it again and again by repeating steps 3-10!

HOW DOES IT WORK:

Like every object around us, our bottle rocket follows three simple rules of physics. These rules were originally written down by a scientist named Isaac Newton over 300 years ago; and we call them Newton’s Laws of Motion because they describe how an object will move when a force (a push or a pull) acts upon it.

The First Law says that when an object has no forces acting upon it (like an empty water bottle sitting on a table) it will never move all on its own, but remain at rest (like when we pick up the bottle, or knock it over!). On the other hand, an object that is already moving will continue to move in a straight line until a force causes it to stop or change its direction (like how gravity, wind, or resistance from the air influences our bottle rocket’s flight).

The Second Law says that objects of higher mass (that is, heavier objects) require more force to get them to move than do smaller objects. In the case of our bottle rocket, the force that makes it blast off comes from a chemical reaction between the distilled vinegar and baking soda. This reaction is the same one that makes foamy lava in the well-known volcano experiment because it produces a lot of Carbon Dioxide gas bubbles. Since the Carbon Dioxide gas is contained within the bottle rocket, pressure will continue to build up until it is strong enough to actually push out the bottle stopper. But consider this: if we used a larger (heavier) bottle for our rocket experiment, but still had the same amount of pushing force from the Carbon Dioxide, would you expect the rocket to fly as high? Why not?

The Third Law says that for every force, there is another force of equal strength and in the opposite direction. In other words: For every action, there is an equal and opposite reaction. For our rocket’s flight, it is easy to see that there is a lot of action (force) pushing downward from the tail-end of our rocket. But it’s less easy to see that this same exhaust flow creates an upward push on the bottle itself, a reaction force that is called thrust. If we had not flipped the bottle upside-down before it blasted off, the exhaust would have escaped upward and our rocket would have actually flown down toward the ground!!!

THE MORE YOU KNOW:

Around the 4th of July, some people like to launch fireworks from their backyard. These commercial fireworks are actually low-grade explosives that would be very dangerous if they exploded at ground level. That’s why fireworks are equipped with a solid-fuel combustion rocket to launch them high above the spectators before safely setting off the gunpowder mortar.

GOING ONE STEP FURTHER:

  1. According to the imaginary laws of Chromodynamic Flight Theory, the more attractive that a rocket is, the higher it will fly…so thoroughly decorate the body of your rocket before launching!
  2. Add a nose cone to the tip of your rocket to make it more aerodynamic (able to move through the air). Try using different materials to create the cone: a paper cone, a cone made from play-dough, or an ice cream cone. Which cone works the best?
  3. Add stabilizing fins to your rocket’s body. Try using different materials to create the fins: cardboard, construction paper, or even paper streamers!
  4. Experiment using different amounts of baking soda and vinegar to achieve the highest possible launch. Or use a different bottle size for your rocket body.

3…2…1…blast off for rocket science!!!

Liquid Hourglass

MATERIALS:

  • Two empty plastic bottles, with bottle caps
  • Strong glue (Super Glue and hot melt glue work well)
  • Electric drill with a bit the same diameter as the drinking straw
  • Vegetable oil
  • Water
  • Food coloring
  • Glitter (optional)
  • Scissors
  • Drinking straw
  • Timer

INSTRUCTIONS:

  1. Clean and dry two plastic bottles, including the bottle caps.  The bottles should be the same size and shape for the best effect.
  2. Once thoroughly dry, glue together the tops of the two plastic bottle caps. Allow enough time for the glue to set completely.
  3. After the glue has set, drill two holes through the tops of the bottle caps.  The holes should be the same size as your drinking straws.
  4. Cut two segments of drinking straw that are about 2 inches long.
  5. Insert the two segments into the holes in your bottle caps.  Slide one straw piece so that it hangs out further on one side, and slide the other straw piece to hang out further on the opposite side.  It is recommended to glue shut any gaps between the straw pieces and the bottle cap, especially if the straw pieces slide around easily.
  6. Fill one bottle with vegetable oil.
  7. Fill the second bottle with water.  You can add a few drops of food coloring to make the water more visible.  You could also add a bit of glitter to add to the effect!
  8. Tightly screw the bottle cap apparatus onto the bottle filled with vegetable oil.
  9. Quickly invert the vegetable oil bottle onto the colored water bottle and screw it tightly shut.  Are the oil and water mixing together? Is this what you had expected would happen?  Why is the oil able to float on top of the water?
  10. Now try flipping the liquid hourglass so that the water bottle is above the oil bottle.  Are the oil and water mixing together now?  What causes the oil to bubble upward, as the water bubbles down?  Are the drops of vegetable oil larger than the drops of water, smaller, or are they the same size?
  11. As soon as you turn over your hourglass, press start on your handheld timer. Wait until the bubbles have nearly stopped flowing before stopping the timer.  Record the time, because this will give you the approximate duration of your liquid hourglass!

HOW DOES IT WORK:

Oil is a hydrophobic substance, which means that it does not mix with water.  Without the help of certain chemicals to bind them together, oil and water molecules repel each other.  Even if you vigorously stir them together, the oil and water will eventually separate back into distinct layers.

Vegetable oil will naturally float on top of the water because it is less dense than the water.  This is also why oil spilled in the ocean will float on the surface of the sea.  This also explains why it is a bad idea to spray water on a grease fire, because the water will sink under the oil and evaporate, launching steam-driven hot oil everywhere!  This also explains why you were probably more than a little bit disappointed when you initially placed the bottle filled with vegetable oil on top of the water bottle.  Nothing really happened because the oil was able to stably float above the water.  But when the water bottle is inverted over the vegetable oil, then small droplets of water begin to sink downward through the oil, displacing equal drops of vegetable oil that float upward!

THE MORE YOU KNOW:

Hourglasses are devices that can be used to measure the passage of time.  Typically, hourglasses are made of two glass bulbs that are joined together at a very narrow neck.  This construction allows grains of sand (or sometimes other types of materials) to trickle from one bulb to the other in a regulated flow. The rate at which the sand flows through an hourglass can be affected by a lot of factors, including: how much sand is in the hourglass, how wide the neck is, or even how large the grains of sand are!!! Hourglasses that are made by professionals are meticulously designed to last for a certain length of time.

Images of hourglasses have been spotted in art from ancient times. One of the earliest forms of an hourglass, called a clesydra or a water clock, was used in ancient Egypt during the 16th century BC!  Modern hourglasses can use very innovative materials to keep track of time, including magnetic granules that make interesting sculptural creations as they interact with a magnet inside of the base!

GOING ONE STEP FURTHER:

  1. Different types of oils can be used in place of vegetable oil.  Some usable oils that might already be available in your house include mineral oil, peanut oil, olive oil, avocado oil, or even safflower oil.  Why might different types of oil flow through the hourglass at different speeds? Can you find a type of oil that actually sinks to the bottom of the water?
  2. Try using thicker or thinner drinking straws.  How might the width of the straw affect the size or timing of the oil and water droplets?  You can also try using longer or shorter lengths of straws to get different flow rates.
  3. Experiment with the offset between the straws going through the bottle caps. Will the hourglass work as well if the straws are removed?  Why do you think it is important for the straws to stick out on opposite sides?
  4. Using a handheld timer and a permanent marker, mark the level of water left in the top bottle after one minute has passed, two minutes, three minutes, etc. Be sure to clearly label each of the minute marks! Invert the hourglass and repeat marking the top bottle after one minute, two minutes, three minutes, etc.  With the gauge markings, your liquid hourglass can be used like a real time piece!

Don’t wait another second, it’s time to make your own liquid hourglass!

Hands on Museum - experiment trying to unmix colored dyes in water

Un-mix the Colors:

MATERIALS:

  • White Corn Syrup
  • 2 Clear Containers (one slightly taller and thinner than the other)
  • 4 Medium-sized Binder Clips
  • Liquid Food Coloring
  • Several small mixing bowls or cups
  • Water
  • Pipettes (drinking straws can also be used instead)

INSTRUCTIONS:

  1. Fill the shorter, wide Clear Container 1/3 full with White Corn Syrup.
  2. Place the taller, thin container into the container filled with syrup.  Fill the inner container with water to anchor it down.
  3. Clip three medium-sized Binder clips around the rim of the outer container, leaving an open space to add the fourth clip later.
  4. Add a small amount of either corn syrup to each of your small mixing bowls.  Stir in different colors of Liquid Food Coloring to each small bowl.
  5. Using a clean pipette for each sample (or by sucking a small amount through a drinking straw), add a small amount of colored syrup directly into the gap between the containers.  Be careful to insert the colored drops a bit below the surface of the clear syrup.
  6. Add the fourth Binder Clip to the rim of the outer container.
  7. Slowly rotate the inner container in one direction, being careful to not jostle the container back and forth inside of the syrup.  What happens to the dots of colored syrup as the inner glass is spun?  Did you expect the colors to mix inside of the container?
  8. After several spins, rotate the inner container in the opposite direction until all of the colors have separated, and have returned to their original places.  Why do the colors “un-mix”?
Hands on Museum - experiment trying to unmix colored dyes in water

HOW DOES IT WORK:

The most commonly accepted explanation for this experiment is a phenomenon called laminar flow.  Laminar flow happens when a fluid moves in thin sheets or layers that glide alongside each other, but never actually mix together.  As the inner container is rotated, the sticky (or viscous) fluid will begin to twist after it, one layer at a time.  As the layers of dyed syrup remain separate within their original layers of syrup, the dots will appear to stretch and blend together; however, the layers of color are simply overlapping, giving the appearance of blending together!  From the side, the overlapping layers of colors give the appearance of mixing together.  But if you look downward into the gap between the two containers, you will actually see how the thin layers have rotated, but not actually mixed together!

When you rotate the inner glass in the other direction, the layers of fluid simply twist back until the layers of colored syrup all line up in their original formation.

Hands on Museum - diagram showing the difference between turbulent and laminar flow of water

THE MORE YOU KNOW:

When you turn on the kitchen faucet at home, you might notice a lot of ripples or bumps in the stream of water—maybe some water droplets even jump out of the stream!  This is because the water is very likely moving in a turbulent flow.  Turbulent flow is characterized by an uneven flow of liquid, causing small swirls and ripples within the stream.

There are special faucet attachments that can create a more stable Laminar Flow stream of water. These faucets produce very clear and glass-like water streams that are often used in decorative fountains and even in amusement park water displays!

GOING ONE STEP FURTHER:

  1. Repeat the experiment using a different viscous substance.  You could try using vegetable glycerin, coconut oil, or even a clear liquid hand soap.  Which substance creates the best “un-mixing” result?  Do the less-sticky substances work better, or the more-sticky substances?
  2. Repeat the experiment using MULTIPLE viscous substances.  For example: You might fill the outer container 1/3 full of vegetable glycerin, but insert drops of colored liquid hand soap!  If the dyed droplets have a different viscosity than the substance around them, will the colors ever fully “un-mix”?
  3. You can completely change the experiment to test a Turbulent Flow.  Instead of using an inner container to twist the fluid, simply mix the dots of dyed syrup with a kitchen spoon.  Once the colors are thoroughly mixed, can you “un-mix” them?  Why or why not?

Happy New Year, science friends! Just go with the (laminar) flow!

Hands on Museum - the Scribble Bot in action

Build a Scribble-Bot:

MATERIALS:

  • AA Battery
  • Double-ended Alligator Clip Leads
  • Wire cutter/stripper
  • Mini DC Hobby Motor (1.5 Volts)
  • Electrical Tape (insulating tape)
  • Duct Tape
  • Small container (such as a plastic cup, short Pringles tube, or even a tin can)
  • Hot Glue Gun
  • Glue Sticks
  • Washable Markers
  • White Paper
  • Craft supplies (especially Googly Eyes!!)
  • Adult Assistant
Hands on Museum - showing tools to create a scribble bot

INSTRUCTIONS:

  1. With help from your adult assistant, cut in half the wire of a double-ended Alligator Clip Lead. Strip away about ½ inch of the plastic coating from each of the cut ends.
  2. Using the electrical tape, attach the exposed copper wire directly to each of the Positive and Negative terminals of the AA battery. Use plenty of electrical tape here, because the tape will help to insulate the wires from possibly shocking anything, and it will keep the wires from getting shaken off from the battery.
  3. Using a hot glue gun, attach the AA battery to the top of your Scribble-Bot (which is actually the bottom of your recycled container). Allow the glue to thoroughly cool down before handling the Bot.
  4. Cut an unused glue stick in half. Attach a piece of the glue stick onto the metal arm of the DC Hobby Motor by pushing the metal directly into the un-melted glue stick. The motor should not be attached in the exact middle of the glue stick, but about ¼ of the way down.
  5. Carefully glue the DC motor onto the top of your Scribble-Bot (be careful to not cover any copper tabs that may be on your motor! We will need to attach wires to them later!). You could either place the motor upright on the top of the Bot OR you could glue the motor sideways, making sure the glue stick arm hangs far enough over the side of the top of the Bot to freely spin. Allow the glue to thoroughly cool down before handling the Bot.
  6. Using Duct tape, secure 3-4 Washable markers around the sides of your Scribble-Bot. The (capped) marker tips should face downward, and all makers should be evenly spaced and leveled.
  7. Now get creative! Decorate your Bot using Googly Eyes, paint, glitter, construction paper, or anything else to make your Scribble-Bot look awesome!
  8. Once your Bot is fully decorated, it’s time to test it out. Place a large sheet of white paper on a clear, flat surface. Remove the marker caps from the Bot’s legs and set them aside.
  9. Carefully attach one of the Alligator Clips to one of the tabs coming from the DC Hobby Motor. Do you notice any movement? Why or why not?
  10. Carefully attach the other Alligator Clip to the other motor tab. Why do both wires need to be attached before the Bot turns on?
  11. Set the Bot on the center of the white paper and watch as it creates a unique piece of Modern Art before your eyes! (You might need to guide the Bot back onto the paper from time to time, as the Bot will likely wander off…but that’s why it’s important to use WASHABLE markers!)
  12. When finished, unplug both Alligator clips from the motor and secure all marker caps. Wash up any stray markings made around your paper. Most importantly, be sure to hang your Scribble-Bot’s masterpiece in a prominent location!

HOW DOES IT WORK:

Electric Motors are used in many different electronics today. They can be found in electric cars, planes, trains, elevators, kitchen blenders, ceiling fans, computer disk drives, electric toothbrushes, vacuum cleaners, washing machines, electric toys, and even in your cell phone to make it vibrate when a friend calls! In each of these cases, the motors use electrical energy to create mechanical energy that can be used to rotate, vibrate, or drive an object. The arm of the motor (called the Drive Shaft) spins around when the motor is connected to the battery by a closed circuit of wires. A circuit is a closed conductive path that allows electricity to flow from a power source (like our AA battery) to run an electric appliance. If any one of the wires comes undone or is unplugged, the circuit can no longer allow electricity to flow and the motor will not run.

Because we attached an unbalanced weight to the Drive Shaft, the spinning weight will cause the Scribble Bot to continuously tilt from one side to another, causing the Bot to jitter around and seem to move on its own. This motion is especially visible when we attach markers to the Bot.

Hands on Museum - the Scribble Bot

THE MORE YOU KNOW:

Motors come in many shapes, types, and sizes. An especially large and powerful electric motor is now responsible for driving the largest truck in the world! The GVW BelAZ 75710 is a Russian mining truck that weighs a whopping 800 tons (1,600,000 pounds) when it is fully loaded. The truck is so massive that it requires four giant electric motors to get it running!

On the other hand, Engineers at the Cockrell School of Engineering at the University of Texas have recently designed and built a type of “nanomotor” that is 500 times smaller than a grain of salt. The microscopic drive shafts can spin 300 times every second, making them faster than a jet engine! Scientists hope that these nanomotors can help to deliver medicine to precisely targeted parts of the human body.

GOING ONE STEP FURTHER:

  1. Experiment using different coloring tools as feet for your Scribble-Bot (Markers, Chalk, Crayons, Pencils, etc). Which ones work the best? Which ones work the least? Can you explain why?
  2. Try out different types of weights for your motor arm (Glue Stick pieces of different lengths, a Clothespin, a rubber Cork, a blob of modeling Clay, etc).
  3. Or try re-placing the same glue stick arm so that it is now more centered on the Hobby Motor. Does the Scribble-Bot move around more or less when the glue stick is centered? Why or why not?

Build your custom Bot, and start Scribbling!

Hands on Museum - showing dry ice smoke
Hands on Museum - tools for handling/using dry ice

Caution: Dry Ice is an extremely cold substance which can cause harm if used improperly. You should always ask for adult assistance when using Dry Ice, and be sure to wear protective goggles and insulated gloves!!

Self Inflating Balloon:

MATERIALS:

  • Balloon
  • Sharpie (Optional)
  • **Dry Ice**
  • Leather Gloves (or other thermal-insulating gloves)
  • Eye Goggles
  • Hammer or Mallet
  • Funnel
  • Salad tongs
  • Adult Assistant
  • Friends to play “Cold Potato”
Hands on Museum - showing dry ice inflating a balloon

INSTRUCTIONS:

  1. (Optional) Inflate the balloon but do not tie it closed. While pinching the balloon shut, you can draw a design, a picture, or even a face (like a Jack-o-Lantern face!) on the inflated balloon using a permanent marker. Let the balloon deflate and allow the marker ink to dry for about 90 seconds.
  2. Insert the neck of a funnel into the opening of the balloon.
  3. Ask an adult assistant to break apart some dry ice into small, pea-sized pieces using a hammer or mallet (and remember to wear your protective goggles and gloves!).
  4. Using a pair of salad tongs or a spoon, place 10-15 small pieces of dry ice into the funnel, and push down the dry ice into the balloon.
  5. Tie off the balloon (without inflating it!).
  6. Hold and shake the balloon in your hands for a few seconds, then pass it to a friend to hold for a few seconds. You can play a very chilling game of “Cold Potato” as the Dry Ice inside of the balloon starts to warm up and seemingly disappear.
  7. Continue to shake and pass the balloon around until you cannot hear any pieces of dry ice moving inside of the balloon. What has happened to the Dry Ice inside the balloon? Have you observed any changes to the balloon itself? How might this change have happened to a sealed balloon?

HOW DOES IT WORK:

Dry Ice is the solid form of Carbon Dioxide (CO2), which we know as a gas at regular temperatures. Amazingly, Dry Ice can only remain solid in very cold temperatures (at least 109 degrees below zero!!!). At everyday room temperature, the Dry Ice does not melt into a liquid like water ice; instead, Dry Ice sublimates, which means that it turns directly from a solid into a gas!

The molecules that make up a solid material are much more densely (or tightly) packed together than the molecules of the same material in its gaseous form. When we place the solid carbon dioxide (the Dry Ice) into the deflated balloon, we are inserting a large amount of CO2 molecules that are very tightly packed together but don’t take up much room inside of the balloon. As the Dry Ice is warmed by the heat of your hands, the solid CO2 will sublimate into carbon dioxide gas. Although there is always the same number of molecules of carbon dioxide in the balloon, the gaseous CO2 takes up WAY more room (it has a greater volume). This causes the balloon to inflate from the inside!

Tank of Frightfully Fun Tricks (Three Tricks in One Treat!)

 MATERIALS:

  • Small Fish Tank
  • Water
  • **Dry Ice**
  • Bubble solution
  • Bubble wand
  • Large plastic mixing bowl
  • Shoelace or long strip of fabric
  • Beverage Pitcher or Measuring Cup with a spout
  • Candles and matches
  • Adult Assistant

INSTRUCTIONS:

  1. Fill a small fish tank to about 4 inches of room-temperature water.
  2. Ask an adult assistant to add 2-3 large pieces of Dry Ice to the tank of water (using insulated gloves and goggles!), and allow the Dry Ice to bubble for 10 minutes.
  3. Using the bubble wand, blow a number of bubbles into and around the Dry Ice tank. Do you notice a difference in how the bubbles act when they float into the tank? What might cause them to act this way?
Hands on Museum - showing experiments with dry ice and bubbles
Hands on Museum - showing dry ice and candles
  1. Light one or more candles and set them in a row on a clear, flat surface.
  2. Using the beverage pitcher or a measuring cup, scoop up some air from around the room. Reach up high and down low to fill the container with air! Slowly pour the air over the candles, watching for any change in the candles.
  3. Again using the beverage pitcher or measuring cup, scoop up some air from inside of the Dry Ice tank. Scoop air as far down as possible, without actually scooping any of the water at the bottom. Again, pour this air over the candles. Do you notice a change this time? Why might the air inside of the tank be different from the rest of the air in the room, and why might it affect the candle flames?
  1. Fill a large plastic bowl (or other wide-mouth container) ¾ full of warm water. Ask an adult assistant to add 1-2 large pieces of Dry Ice to the bowl (using insulated gloves and goggles!). Now wouldn’t THAT look awesome as a Halloween decoration?!?!
  2. Thoroughly soak a shoelace or a thin piece of fabric in a bowl full of bubble solution.
  3. Using your finger, coat the rim of the plastic bowl with a layer of bubble solution.
  4. Hold the bubble-soaked straight taught and run it across the surface of the bowl. Make sure the string touches both sides of the bowl as you drag the string from one end of the bowl to the other. You should see a bubble film forming on the bowl’s surface. Be patient if the bubble film doesn’t form on your first attempt! Keep trying until you get it just right!
  5. Once the bubble surface has formed, sit back and watch as a mega-bubble grows from the container! Be extra observant of the moment the bubble eventually pops! What happens to the cloudy air inside of the bubble? Does it rise upward or does it fall downward?
Hands of Museum - dry ice inflating a bubble

HOW DOES IT WORK?:

Why do the bubbles float inside the tank? The carbon dioxide (CO2) gas that is formed from the sublimation of the Dry Ice is actually heavier than your breath that is filling the bubbles. The lighter bubbles are buoyant (able to float) on the surface of the heavier CO2 gas layer—even though you cannot see the invisible carbon dioxide!

Why do the candles go out when you pour the tank-air over them? While the air inside of the tank will get a bit cooler due to the very cold Dry Ice, the temperature is actually not the reason why the candles are extinguished. Also, the air pouring from the container is definitely not moving fast enough to “blow out” the candles. Fire needs 3 things to burn: a source of heat for ignition, fuel to burn, and oxygen to feed the flame. When the dense carbon dioxide pours out of the pitcher, it acts much like an invisible liquid that pushes away the oxygen around the candle flames. Without its constant oxygen source, the fire quickly goes out.

Why does the mega-bubble grow without having to blow it up? Much like the Self-Inflating Balloon experiment, the sublimating Dry Ice becomes COgas. The gas is far less dense than the Dry Ice, and takes up a lot more space. The bubble solution film acts as a stretchy lid that will contain the sublimating CO2 gas inside the bowl, but is still able to grow quite large as the expansive gas is pushes outward from inside. When the bubble finally bursts, the misty air flows downward because it is cooler and more dense than the air around it…and so it sinks!

THE MORE YOU KNOW

Since its discovery in 1835 by the French Inventory Adrien-Jean-Pierre Thilorier, Dry Ice has been used as a packing and preserving coolant. Because Dry Ice does not leave behind pools of liquid after it warms, it is much preferred over “wet ice” (frozen water) for the purpose of refrigerated commercial shipping.

When Dry Ice is added directly to a food product (like when making ice cream with CO2, freezing fruit, or carbonating a soda product), the carbon dioxide will react with water molecules in the food to create carbonic acid. This chemical gives the food a sour, acidic flavor, but can also add a very distinct fizz!

***Remember to ask an adult for assistance with these chilling Dry Ice experiments.***

And please use your new Freezing powers for Treats, and not for Tricks this Halloween!!!