Bill's Unofficial Cub Scout Roundtable
A compendium of Ideas For Cubmasters, Den Leaders and those who help them.
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Good Turn For America
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3 Magic Words
Everyone likes to experiment. The Scientist Activity
Badge will teach some of the basic laws of science and
how to prove them through experiment.
Last Update: 7/20/09
To acquaint Webelos with basic laws of physics. To give boys the opportunity to perform experiments. To introduce boys to atmospheric science. To teach boys a little about optics. To demonstrate a few "mysteries" of science
RELATED BOY SCOUT MERIT BADGES
Astronomy, Chemistry, Space Exploration,
Webelos Den Activities, pp. 72-77.
For best results, follow this procedure:
Two Rivers Council
Not all scientists are old men with beards.
Your Scouts may find particle physicist Dr. Brian Cox interesting. He is one of the leading scientists at CERN: the world's largest and most powerful particle accelerator. Cox's mission is to search for a hypothetcal atomic particle called the Higgs boson, that has never been seen or detetected before but may shed some light on what gravity is and where it comes from, if they can recreate one.
Dr. Brian Cox
It seems that not much has been learned about gravity since Newton
published his famous Universal Law of Gravitation in 1686. Newton knew that
gravity comes from mass but our best scientists haven't found where
mass comes from. None of the bits - like protons and electrons that
make up the atoms and molecules we are all familiar with - seem to have
any mass at all. Yet a big rock or a gold bar has lots of mass and, of course,
lots of gravity.
Even stanger still is that astronomers tell us that most of the gravity in the universe comes from places where there is little matter at all only the occasional hydrogen atom. They call this "dark matter" which probably translates to, "We have no idea what it is".
Interesting Side Note: Brian financed his education at Manchester University by playing keyboard in the rock band Dare. You can view clips of him on stage along with other Cox videos on youtube.
The Scientific Method describes the principles that guide scientific research and experimentation. The scientific method occupies itself with the "how of things" in a manner that faithfully follows a set of accepted rules and procedures.
The scientific method is what working scientists do to earn a living.
There are certain principles and processes of discovery and demonstration that are considered characteristic of, or necessary for, scientific investigation. These generally involve:
Scientists are engaged in one or more these activities.
Some scientist will work at all of them.
Hypothesis: A scientific hypothesis is an idea that has not been tested by the ability to predict future test results.
Example: In 1912, Alfred Wegener and Frank Taylor first proposed the hypothesis that 200 million years ago the Earth had only one giant continent, from which today's continents broke apart and drifted into their current locations. Wegener used the fit of the continents, the distribution of fossils, a similar sequence of rocks at numerous locations, ancient climates, and the apparent wandering of the Earth's polar regions to support his idea.
Most scientists at that time did not accept this hypothesis because they could not understand how continents could move through the hard rock of the ocean floor. Recent evidence from ocean floor exploration shows that the ocean floor itself moves and carries the continents along. This and other studies has rekindled interest in Wegener's hypothesis, and lead to the development of the theory of plate tectonics. Today, most scientists accept the theory of continetal drift. See USGS.
Theory: A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.
As Theories can become accepted if they are able to make correct predictions and avoid incorrect ones. Theories which are simpler, and more mathematically elegant, tend to be accepted over theories which are complex. Theories are more likely to be accepted if they connect a wide range of phenonomena. The process of accepting theories is part of the scientific method.
Circle Ten Council
Aren't they the same thing?
Not quite. Though they use many of the same ideas and methods, scientists and engineers are somewhat different.
What do scientists want?
Scientists want to know how the universe works. They may see it as an enormous jigsaw puzzle to solve for its own sake. Some things they find are useful right away, others not (though much of what scientists have found in the past has turned out to be useful in some way). Though they certainly want to help people, their major goal is understanding, not usefulness.
What about engineers?
Engineers try to use the facts of science and math to do things that are useful to people. Many engineers are designers -- designing the many products that we use in the world, from computers to cars to camera lenses.
What do they have in ../common?
Quite a few things, actually. Scientists and engineers both use the facts and methods of science, and both often use MATH and COMPUTERS in their work.
Contact a local high school's Physics Department Chairperson to see if anyone has some neat demonstrations they can do at the Pack Meeting. For example, you might find someone who does demonstrations with Van DeGraff Generators and Tesla Coils. These make super impressive exhibits that the boys and their families will talk about for years to come.
BB, York Adams Council
"The pressure of a liquid or a gas like air is the same in every direction if the liquid is in a closed container. If you put more pressure on the top of the liquid' or gas. the increased pressure will spread all over the container."
A good experiment to demonstrate air pressure is to take two plumber's force cups (plumber's friend) and force them firmly against each other so that some of the air is forced out from between them. Then have the boys try to pull them apart.
When you drink something with a straw, do you suck up the liquid? No! What happens is that the air pressure inside the straw is reduced, so that the air outside the straw forces the liquid up the straw.
To prove this fill a pop bottle with water, put a straw into the bottle, then seal the top of the bottle with clay, taking care that the straw is not bent or crimped. Then let one of the boys try to suck the water out of the bottle. They can't do it!
Remove the clay and have the boy put two straws into his mouth. Put one of the straws into the bottle of water and the other on the outside. Again he'll have no luck in sucking water out of the bottle. The second straw equalizes the air pressure inside your mouth.
Place about 1/4 cup baking soda in a coke bottle. Pour about 1/4 cup vinegar into a balloon. Fit the top of the balloon over the top of the bottle, and flip the balloon so that the vinegar goes into the bottle. The gas formed from the mixture will blow the balloon, up so that it will stand upright on the bottle and begin to expand. The baking soda and vinegar produce C02, which pushes equally in all directions.
The balloon which can expand in all directions with pressure, will do so as the gas is pressured into it.
For this next experiment you will need:
A medicine dropper,
a tall jar, well filled with water;
a sheet of rubber which can be cut from a balloon;
and a rubber band.
Dip the medicine dropper in the water and fill it partly. Test the dropper in the jar - if it starts to sink, squeeze out a few drops until it finally floats with the top of the bulb almost submerged. Now, cap the jar with the sheet of rubber and fix the rubber band around the edges until the jar is airtight. Push the rubber down with your finger and the upright dropper will sink. Now relax your finger and the dropper will rise. You have prepared a device known as a 'Cartesian Diver'. The downward pressure on the rubber forces the water up into the bottom of the diver, compressing the air above it, producing the effects of sinking, suspension and floating, according to the degree of pressure applied.
This is a fun demonstration of the effects of water pressure.
You will need a water-proof bag strong enough to stand the pressure. The Webelos den leader stands on the bag.
Clamp a plastic tube to the input of the bag and hold the free end of the bag higher than the head of leader.
A Webelos scout then pours water through a funnel into the tubing. As the bag fills and the level rises up through the tube, the pressure in the bag will lift the leader.
Another adult should make sure that the Webelos Scout pouring the water is safe when he climbs high enough to reach the top of the tube.
The clamp on the bag/tube must be strong and tight enough to take the pressure.
From Sean Ballard, WDL of Pack 122, Portland OR.
Fill a drinking glass to the very top with water. The water should spill over the top a bit.
Carefully lay the cardboard square to completely cover the top the glass. Holding the cardboard on top, turn the glass over until it is straight upside down. Stop holding the cardboard on. It will stay on by itself.
Fasten a white disc, 3/4-in diameter on a 3 foot piece of white thread. Have someone hold the thread so the disc can swing like a pendulum. Start the disc swinging in a perfectly straight line and view it from a distance of three feet against a plain wall. Notice how the disc swings in a line like a pendulum. Hold a sunglass lens over one eye. Observe the path of the swinging object again. The movement will no longer be in line but in a circle. If you switch the lens to the other eye, the movement will appear to be in the opposite direction.
Principle demonstrated: Shows how important it is for the eyes to receive similar images.
This measures the density of a liquid. An object can float in a liquid only if it is less dense than the liquid. Prove this by placing a fresh egg in a glass of water. The egg will sink. Then add 1 tablespoon of salt to the water and the egg will float. Try sticking a thumbtack into a pencil eraser and place the pencil in water, point up. Mark the waterline on the pencil. Add salt to the water. The pencil will ride higher in the water.
WHY? BECAUSE SALT WATER IS MORE DENSE!
BB Viking Council
The salt water of the seas is much denser than the fresh water of rivers and lakes, and therefore it is easier to float in the ocean. Show this by filling two glasses half full of water. In one of them, mix in about 10 heaping teaspoons of salt.
Try floating an egg in each glass. In which glass does the egg float?
Now take the eggs out of both glasses. Carefully and slowly, pour the fresh water into the salt water glass. Gently lower an egg into the water. It should float (remain suspended) at the salt water level.
Fill a 12 ounce glass three fourths full of water. Add a tablespoon of baking soda and stir until clear. Drop raisins into the glass. Pour vinegar into the glass. Use as much vinegar as it takes to make the raisins come to the top of the water. Bubbles will appear, and the raisins will "dance."
Mixing vinegar and baking soda together forms a gas called carbon dioxide. Bubbles of carbon dioxide stick to the sides of the raisins, act like air bags, and float the heavy raisins to the surface. At the surface the bubbles break, the raisins sink again, and the process starts all over.
Crystals are not alive, but they can grow. Growing crystals requires a little time and patience. If you have both (plus a few other ingredients), you can grow your own crystal gardens.
You can also use pieces of sponge, coal, or crumbled cork to grow the crystals on. Crystals are formed because the porous materials they grow on draw up the solution by capillary action. As the water evaporates on the surface, deposits of solids are left behind, forming the crystals. As more solution is drawn up, it passes through the crystals that have already formed, depositing more solids on their surfaces, causing the crystals to grow.
I did find bluing at an Albertson's. Many stores no longer carry it.
a clean glass,
1/4 cup of water,
a teaspoon of salt,
red and green liquid food coloring,
a strip of paper towel about one inch wide,
Instructions: Mix together a few drops of the red and green food coloring. Make a spot on the paper towel with this mixture about one inch from the bottom. Let dry.
Pour the water into the glass and stir in the salt. Place the pencil across the top of the glass. Hang the paper strip over the pencil so that the end of the paper with the spot just dips into the water.
Wait a few minutes, and the water will slowly climb up the paper. The spot will separate into patches of red, yellow, light green and blue.
Why? The food coloring is a mixture of different colored chemicals. As the salt water climbs up the paper it dissolves the chemicals. Some chemicals rise higher than others.
Separating chemicals this way is called Chromatography. When the chemicals are separated they can be identified more easily.
BB Viking Council
two Ping-Pong balls,
two feet of thread,
some mending tape and
a drinking straw.
PROCEDURE: Tape each ball to an end of the thread. Hold the center of the thread so that the balls dangle about one foot below your fingers and about one or two inches apart. Have the boys blow through a straw exactly between the balls, front a distance of a few inches. Instead of being repelled, the balls will be attracted to each other.
EXPLANATION: The air current directed between the Ping-Pong balls reduces the intervening air pressure. Stronger pressure from the far sides pushes the balls together. The strength of the air front the straw will determine how close the balls will come.
If you pull gently on the string, the truck will move at least until the block falls oft the "wheels." But if you give a hard jerk the string will break.
Why? Because the inertia of the bricks is too much for the string. (See the Webelos Scout Book, Scientist section, for an explanation of inertia.)
A Webelos Scientist demonstration of the Law of Archimedes. The boat floats easily but the bail sinks. Why? Because the boat displaces much more water than the ball.
Half fill the bottle with vinegar. Wrap a small quantity of bicarbonate of soda In facial tissue and put it In the bottle.
Immediately put the cork in. Lay the bottle on two parallel pencils as shown. When the vinegar and bicarbonate of soda react, they form carbon dioxide. When the gas builds up, the cork wilt pop and the reaction will thrust the bottle forward on its rollers
Alessandro Volta, an Italian physicist, produced electricity by chemical reaction in 1800. He did this with a device that became known as a voltaic cell. It was the first wet cell battery. Volta's battery was made with pairs of zinc and silver pieces. The electric current ran from the zinc to the silver through pieces of board soaked in salt water. You can make your own simple voltaic cell.
piece of copper wire
Straighten out the paper clip and copper wire. They should be
about the same length.
Thrust both wires deep into the lemon. They should be side by side, but not touching.
Put the free ends of the wires to your tongue. The slight tingle and metallic taste you feel is due to the passage of electrons through the saliva on your tongue. The acid in the lemon acted as an electrolyte. An electrolyte is a substance that is not metal that carries electricity. The chemical reaction caused electrons to build up on one of the wires and decrease on the other wire.
CONCLUSION: When you put the free ends of the wires to your tongue, you closed the circuit between the two wires. Electrons flowed from the wire with more electrons, through your saliva that acted as a conductor, to the wire with fewer electrons. The entire system of lemon, wires, and saliva is a simple battery. It is similar to the first battery made by Alessandro Volta.
Place two teaspoonfuls of baking soda in the bottom of a quart glass bottle. Drop a burning match into the bottle. It will continue to burn. Next pour four teaspoonfuls of vinegar on top of i the baking soda, being careful not to pour directly onto the match. i Watch what happens. The seething, foaming mass is carbon dioxide, i released from the soda by the vinegar.
What happens now to a lighted match? Why? Is carbon dioxide gas heavier than air? Than oxygen? Tip bottle slowly over it lighted candle. What happens? The heavy gas can even be poured so the flame flutters and may go out. This is the principle behind some fire extinguishers.
Two Rivers Council
The Beaufort Wind Scale was originally devised by Sir Francis Beaufort to describe wind speed in chart form. By watching the effect of wind on objects in the neighborhood, it is possible to estimate its speed.
Copy the scale on a large sheet of cardboard and hang it in your den meeting place.
Effect of Wind
Sam Houston Area Council