LET’S GET PHYSICALLET’S GET PHYSICALPRESENTED BY:NANCY GILESPEGGY PATE

DANETTE TAWBUSHDEBBIE GARRISON

Alabama Science in MotionAthens State University

Athens, AL

THE INCREDIBLE “EDIBLE” CANDLE

Procedure:Advanced preparationUse a cork borer to bore out several cylinders from an apple. Dip these inlemon juice to prevent browning. Trim several long thin slivers ofalmond to serve as wicks. Insert an almond wick into one end of eachapple cylinder.DemonstrationTell the students you want them to make and record as manyobservations as they can about a particular object. Inform them that they willbe limited to one minute. Bring out the candle and light it. After the studentshave been recording for 30-45 seconds, ask them to observe carefully. Quicklyinsert the burning “candle” into your mouth and eat it. Discuss the differencebetween true observations and inferences. Ask the students to identify the true observations in their lists and check off the inferences

Source: Blockbuster Science Activities by Phil Block, 1995

Fred the Friendly Helper

Materials:BalloonStringSharpieTapePiece of SilkProcedure:Inflate a balloon and tie. Using a Sharpie draw a face on 1 side of balloon. Tie a

piece of string several inches long to the balloon. Using the string, suspend the balloon from ceiling or door facing. Create a static charge by rubbing the side of the balloon with the face on it several times with the silk cloth. When you move near the charged side of the balloon it will be pulled toward you.

Explanation:Demonstrates the effects of static charges

BALLOON CAN RACER

Materials:BalloonPiece of silk or wool clothProcedure:Turn an empty soft drink can on its side. Rub the side of an inflated balloon briskly against your hair (you can use the silk or wool clothinstead of your hair if you choose). Hold the charged surface of the balloon near the can to make the can roll.

Explanation:Demonstrates the effects of static charges

Source: Invitations to Science Inquiry, Tik L. Liem

UNPEPPERING THE SALTMaterials:Mixture of salt and pepperInflated balloonProcedure:Sprinkle a small amount of salt and pepper on a plate or

tabletop. Rub an inflated balloon against your hair a couple of times

and hold it near the salt-pepper mixture. Observe what

happens.Explanation:Demonstrates the effects of static charges.

Source: Invitations to Science Inquiry, Tik L. Liem

Skewer Through the BalloonMaterials: 9 inch balloon SkewerVegetable oil SharpieProcedure:The “trick” is to determine the location where the latex molecules are under the least amount of stress or strain. Using a sharpie draw heavy dots (similar in size) randomly over the surface of the balloon. Inflate the balloon and observe the area where the dots are stretched the least. This is the location through which to insert the skewerSource: Steve Spangler

Balancing ActMaterials:1 Popsicle or craft stick1 12-inch of 20 or 22 gauge soft wire2 paper clipsProcedure:Bend the wire approximately in half. Wrap wire around the stick about 2 times at a

pencil mark, ending up with the 2 ends of the wire about the same length. Curve the wire ends down, away from the long end of the stick. Form small hooks at the end of the wires. Attach a paper clip to each hook and close each hook. Try balancing the stick on a fingertip. If it tips over and falls off, observe which way it tipped. Try bending one arm slightly in or out and observe how it balances now.

Explanation:Demonstrates center of gravity

Psychedelic Lava Light

Materials:Test tube with lid OilFood coloring Alka SeltzerWaterProcedure:Fill the test tube ½ to ¾ full of oil. Add a capful of water. Add one drop of food coloring. Add half an Alka Seltzer tablet, quickly replace the cap on the test tube, and observe what happens.

Explanation:The water is more dense than the oil so it sinks in the oil. The Alka Seltzer dissolves in the water forming gas bubbles that rise up through the oil. The food coloring makes the bubbles more easily seen.

Source: Steve Spangler

Dancing Raisins (Popcorn)

Materials:

Large wide mouth container

Raisins or popcorn

Sprite or Club Soda

Procedure:

Pour Sprite into container. Drop raisins or popcorn into liquid. Observe the rise and fall of the raisins(popcorn) as they dance before your eyes.

Explanation:

The raisins float to the top because gas bubbles stick to the sides of the raisins, making them more buoyant. Buoyant means that something floats more easily. The bubbles make the raisins float the way a life jacket makes a person float.

Bernoulli’s BallMaterials:Planter’s Cheez BallsFlex strawsScissorsProcedure:Bend the straw to form an elbow. Clip the short end of the

straw about four times to form a resting place for the cheese ball. Place

one cheese ball on the holder and blow through the other end of

the straw. The cheese ball is suspended over the holder.Explanation:Air is rushing around the cheese ball. As the air rushes there is a small area of air above and below the cheese ball that remains stationary or still. That stationary air “suspends” the cheese ball in the air.

Mini Marshmallow Masher*Materials:

SyringeMini marshmallowMarkerProcedure:Draw a face on the marshmallow with the marker. Remove the plunger from the syringe and place the marshmallow in the syringe. Replace the plunger and push it as far down as possible without mashing the marshmallow. Place one finger on the end of the syringe, pull the plunger out to the end of the syringe and observe the marshmallow. Push the plunger into the syringe and observe the marshmallow.

Explanation:Pulling the plunger decreases the air pressure inside the syringe. There is now more air pressure inside the marshmallow than outside, thus the marshmallow expands. Pushing the plunger into the syringe increase the pressure inside the syringe. Now there will be more pressure outside the marshmallow than inside, so the marshmallow compresses.

Cloud in the Bottle*Materials:Soda bottle Rubbing alcoholMatchesProcedure:Add 5-10 mL of rubbing alcohol to an empty soda bottle and tightly cap the bottle. Shake the bottle to saturate the air in the bottle with the liquid. Open

the bottle, light a match, and blow it out. Quickly drop the smoking match into the bottle,

and immediately cap the bottle. Squeeze and release the bottle several times to

form a cloud. Squeeze the bottle and the cloud disappears. Release the bottle and the

cloud reforms.

Explanation:The cloud is formed because the smoke particles act as nuclei for the condensation of the liquid. The cloud disappears because the temperature of the gas in the bottle increases when the bottle is squeezed, evaporating the liquid droplets. Likewise, the temperature of the gas decreases when the bottle is released causing the liquid to condense

Source: Flinn Scientific

Rainbow TubeMaterials: 5 colored salt-water solutionsProcedure:Obtain 5 colored salt-water solutions. Create a density column of the solutions in

yourstraw using the following guidelines.

1. Dip the straw into a solution to a depth of about 1 cm, putting your finger over the end of the straw, removing the straw from that solution, and lowering it into the next solution about 2 cm. Remove the finger from the top of the

straw to allow the next layer to move into the straw. Finally, put a finger over the straw and lift it out vertically

2. If the solutions have mixed, the more dense solution was on the top, and the procedure should be done in reverse order to get 2 distinct layers.

3. While doing this procedure it is important to keep the straw vertical at all times. If it is slanted, the solutions tend to mix.

Determine and record the density order of the solutions from more dense to least dense.

Teacher Notes:Coarse kosher salt works well to create a clear solution, and almost any varying

set of saltand water concentrations with food coloring work well.

The Great Pepper RaceMaterials:Pepper WaterToothpick Dishwashing liquidPetri dish

Procedure:Fill a Petri dish or other small container with water. Sprinkle pepper on

the surface of the water. Dip the end of a toothpick into the dishwashing liquid, and then insert this end into the center of the container of water and pepper. Observe what happens to the pepper.

Explanation:When soap is added to the water the surface tension of the water is

disrupted and the soap spreads over the surface. As it spreads it moves the pepper flakes along with it.

Bubble GeometryMaterials:Raisins ThreadToothpicks Bubble solutionSmall containerProcedure:Using the toothpicks and raisins, build geometric shapes such as

cubes, rectangles, tetrahedrons, or shapes of your own design. Tie a piece of

thread to your structure. Dip the structure into a small container of bubble

solution and slowly pull it out. Observe the action of the film.Explanation:As you lift the frame out of solution, the soap film flows into a state of minimum energy. The soap film is in a state of minimum energy when it is covering the least possible amount of surface area. The intricate shapes you see inside the frame represent the minimum area the soap film can cover.Bubble solution – Mix 1 cup of Dawn dishwashing detergent, 1 gallon water, and 50-60 drops of glycerin.

Cat’s Meow

Materials:Milk Petri DishFood coloring ToothpickDishwashing liquidProcedure:Fill the petri dish with milk. Place a drop of each of the 4 different food colors on the milk. Dip the toothpick into liquid dishwashing detergent, then dip this end of the tooth pick into the milk in the middle of the dish.

Observe what happens.Explanation:Adding the soap to the milk breaks up the fat globules in the milk and disrupts the surface tension of the water in the milk. This creates movement in the milk. The food coloring shows this movement

Liquid White LightMaterials:3 light sticks (red, green, blue)4 small plastic cupsWhite paper towels1 sharp knifeProcedure:Unwrap the light sticks. Activate each light by carefully bending it until the glass ampule inside breaks. Shake each light stick well. Shake all the

liquid and glass down to the bottom of one of the light sticks and CAREFULLY slice off the top of each tube. Decant each glowing liquid into a separate clean cup. Mix all 3 liquids into a fourth cup one at a time. Dip a white paper

towel into the liquid. Once wetted with the solution, remove the paper towel and observe the light being emitted – it is white.Source: Educational Innovations, Inc., Liquid Light Demo Kit, Item

#33-6

Chemical HandwarmersMaterials:25 g Iron powder 1 g sodium chloride 1 Tbs. small vermiculite (might try sand) plastic baggy Procedure:1. Mass 25 g of iron powder or very fine iron filings and 1 g of sodium chloride.

Place these in a small plastic bag. Shake the bag to mix. 2. Add about a tablespoon of vermiculite to the bag and shake well. 3. Add 5 ml of water and seal the bag. Shake it. The reaction will start after

about a minute. Explanation:Observe the heat energy that is given off during the oxidation of iron.

Demonstrates an exothermic reaction.

Card FlipMaterials:CoinIndex cardWide mouth containerProcedure:Place an index card on a top of the container. Place a coin in the center of the

index card. Flick edge of index card with enough force to cause the index card to move in a horizontal motion. The penny should fall into the container.

Explanation:Demonstration of Newton’s 1st Law of Motion (Law of Inertia).

Whirly-BirdMaterials:Wooden pencil with an eraser on one end Flexible soda strawSewing pin Plastic tapeRound party balloonProcedure:Slip the nozzle end of the balloon over the end of the balloon farthest from the

bend. Use a short piece of plastic tape to seal the balloon to the straw. Bend the opposite end of the straw at a right angle. Lay the straw and balloon on an outstretched finger so that it balances and mark the balance point. Push the pin through the straw at the balance point and then continue pushing the pin into the eraser of the pencil. Blow the straw to inflate the balloon and then let go of the straw.

Explanation: The balloon and straw spin because of the action-reaction principle described in

Newton’s Third Law of Motion. The balloon produces and action by squeezing on the air inside causing it to rush out the straw. The air, traveling around the bend in the straw, imparts a reaction force at a right angle to the straw. This result is that the balloon and straw spins around the pin.

Singing GlassMaterials: Glass or wine goblet, WaterProcedureWet your finger with water, and then move your finger around the edge

of the glass exerting light pressure until you get a sound. Pour a little water in the glass and notice the pitch change.

Explanation:When the finger is rubbed against the rim of the glass, it catches and

slides in very quick succession, causing the molecules of the glass to vibrate. As soon as the first few vibrations are produced, they make the glass resonate. By adding water to the glass, the vibrating mass increased and thus the pitch got lowered.

Source:Invitations to Science Inquiry, Tik L. Liem

Santa Cup Amplifier

Materials:Cup Toothpick String MarkerSponge Nail Felt GlueProcedure:Punch a hole in the bottom of a cup with a nail. Thread a piece of string about 60 cm long through the hole. Tie the toothpick to the string so that the toothpick is on the outside of the cup. Tie the opposite end of the string around a small piece of sponge. Cut a beak and comb from the felt and secure on the cup with glue. Dampen the sponge with water, wrap the sponge around the string and pull it down the length of the string away from the cup.

Explanation:Pulling the sponge down the string causes the string to vibrate which, in turn, causes the walls of the cup to vibrate. The sound waves produced inside the cup hit the walls, bounce back and reinforce each other causing the sound to be amplified.

The Disappearing BeakerMaterials:WessonTM oil (Regular, not lite)2 Pyrex beakers (one beaker must be small enough to fit into the other beaker)Procedure:Put the smaller beaker into the larger beaker. Fill the smaller beaker and the largerbeaker with WessonTM oil. Notice that the smaller beaker becomes difficult to see.

Explanation:When light passes from air into glass, it slows down. The change in speed causes the light to reflect and refract as it moves from one clear material (air) to another (glass). Every material has an index of refraction that is linked to the speed of light in that material. The higher a material’s index of refraction, the slower light travels through that medium. The smaller the difference in speed between the two clear materials, the less reflection will occur at the boundary, and the less refraction will occur for the transmitted light. If a transparent object is surrounded by another material that has the same index of refraction, then the speed of light will not change as it enters the object. No reflection and no refraction will take place, and the object will be invisible.WessonTM oil has nearly the same index of refraction as Pyrex glass.