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Everyone likes to experiment. The Scientist Activity Badge will teach some of the basic laws of science and how to prove them through experiment.


 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


Astronomy, Chemistry, Space Exploration, Weather, Aviation, General Science.



  • Webelos Den Activities, pp. 72-77.
  • Boys' Life.
  • Science Digest magazine.
  • United States Weather Bureau.
  • Local optometrists/ophthalmologists.
  • Jr. high and senior high science teachers.


  • exhibits.
  • Visit an optometrist's or ophthalmologist’s office and ask him/her to explain the tools of the
  • trade.
  • Arrange to have the boys visit a school science lab to see those tools.
  • Grow crystals or a coal garden.


Remember the Scientist Activity Badge is it "doing" badge, not a "watching" badge.
For best results, follow this procedure:

1. Demonstrate the experiment.
2. Explain the experiment.
3. Ask questions to test understanding.
4. Allow Webelos to do tile experiment.
5. Have each boy log the experiment.
6. Have each boy explain tile experiment.
7. Ask again for questions

What does a scientist do?

    • A scientist studies things to learn how they behave and why.
    • Scientists try to find out the laws of nature about the things they study.
    • People can use these rules or laws in making things.
    • While working on this activity badge, you will learn a few of the main ideas in physics.
    • Physics is a science with several branches.
    • One of these branches will be weather.
    • You can learn a little about weather in these activity badge requirements.
    • Another branch of physics is called optics. You will have a chance to learn something about sight and find out how your eyes work.
    • Scientists learn a lot by experimenting or trying things out.
    • Try things for yourself.
    • Scientists take nothing for granted.
    • They may be sure an idea is true, but they always test it, if possible, to make certain they are right.


  • Visit an industrial lab

  • Visit a planetarium

  • Visit a TV news weather station

  • Visit a high school or college science lab

  • Go to a community science fair

  • Have a magic show with each boy doing an optical illusion

  • Talk about the various branches of science and how they differ.

  • Do the atmospheric pressure tests or balance tests in the Webelos book.

  • Make fog

  • Grow a crystal garden.

  • Do the inertia experiments in the Webelos book.


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.


  • Lab technician

  • Nurse

  • Zoologist

  • Nuclear physicist

  • Weather forecaster

  • X-ray technician

  • Science teacher

  • Researcher


Visit an eye specialist and learn how the eyes work.
Visit the control tower of the Metropolitan Airport or visit a Municipal Airport.  Learn about the principles of fight.
Tour an airplane and look at all the control dials.


        Materials needed:
             1 gallon clear glass or plastic jar with a wide mouth
              rubber glove (Playtex brand works well)
              tap water

        ADULT HELP
        Barely cover the bottom of the jar with water. Hang the glove inside the jar with the fingers pointing down and stretch the glove's open end over the mouth of the jar to seal it .  Insert your hand into the glove and pull it quickly outward without disturbing the jar's seal.
        Nothing will happen.  Now remove the glove, drop a lit match into the jar, and replace the glove.  Pull outward on the glove once more. Fog forms inside the jar when you pull the glove outward and disappears when the glove snaps back.  The fog will form for 5 to 10 minutes before the smoke particles settle and will have to be replenished.

        Why?  Water molecules are present in the air inside the jar but they are in the form of invisible gas molecules, or vapor, flying around individually and not sticking to one another.  When you pull the glove outward, you allow the air in the jar to expand.  In expanding, the air must do work, which means that it loses some of its thermal energy, which in turn means that its molecules (including those of the water vapor) slow down slightly.  This is a roundabout way of saying that the air becomes cooler! When the water molecules slow down, they can stick to each other more easily so they begin to bunch up in tiny droplets.  The particles of smoke in the jar help this process along.
        The water molecules bunch together more easily when there is a solid particle to act as a nucleus. When you push the glove back in, you warm the air in the jar slightly, which causes the tiny droplets to evaporate and again become invisible.

        An Added Treat
        Shine a slide projector through the cloud you make in the jar.  When the smoke is fresh, the droplets will be large compared to all wavelengths of visible light and the light they scatter will be white.  As the smoke dissipates, the water drops will become smaller and the light scattered will created beautiful pastel colors at some viewing angles


 "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.


 The Upside-Down Glass That Won't Spill

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.




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.



crystal garden


Colorful, small, delicate crystals grow on a charcoal or brick surface. 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.


Materials needed: 

  • 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

  • a pencil


  • 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.

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.


two Ping-Pong balls,
two feet of thread,
some mending tape and
a drinking straw.


  • 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.

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.) inertia cart

displacement experiment jet powered bottle
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
fresh lemon
paper clip. 


  • 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. 

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 the baking soda, being careful not to pour directly onto the match. Watch what happens. 

  • The seething, foaming mass is carbon dioxide, 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.


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.

Title           Effect of Wind
Calm   Smoke rises vertically
Light   Air Smoke drifts 
Light   Breeze Leaves rustle
Gentle  Breeze Flags fly
Moderate Breeze Dust, loose paper raised 
Fresh Breeze   Small trees sway
Strong Breeze  Difficult to use umbrellas
Moderate Gale   Difficult to walk 
Fresh Gale   Twigs break off trees
Strong Gale   Slight damage to roofs
Whole Gale   Trees uprooted
Storm    Widespread damage
Hurricane   Devastation 
Less than 1
1 - 3
4 - 7
8 - 12
13 - 18
19 - 24
25 - 31
32 - 38
39 - 46
47 - 54
55 - 63
64 - 75
Above 75



We live under a blanket of air called the earth's atmosphere.  The air in the atmosphere exerts pressure of almost fifteen pounds per inch on every surface of earth.


Fill a glass to overflowing and lay a piece of cardboard atop it.  Support the card with one hand, turn the glass upside down, and remove your hand from the card.  The card does not fall.  It remains on the glass and allows no water to escape.  Why?  The air pressure from below the cardboard is greater than the pressure of the water above and presses the card tightly against the glass.


If we compress air (put more air into the same space), we will increase its pressure and can use it in machines.  Your bike tires use compressed air to give you a smooth ride.


Webelos Scientist Activity Badge

The Lab, Australian Broadcasting Corporation

Bubble-ology and Bernoulli

On-Line Science Experiments

Science Links K-12

An online periodic elements table