Girl Scout Scientific Achievement Badge
Answers & Explanations Packet
Our advice to troop leaders and supervisors:
Inspire curiosity, confidence and enthusiasm in your
Girl Scouts! Be confident even if you do not feel
comfortable with your answers/explanations because
the process of learning matters as much as the
answer itself. Please feel free to ask us questions!
The Daisy, Brownie, Junior, and Cadette requirements
have the same foundations but each packet is a little different. The packets for the older scouts require more indepth investigations. The answers and hints in this adult/
leader guide are full and lengthy explanations, which can
be used in their entirety for the older scouts or reduced for
the younger scouts in whatever way you feel is appropriate
for your group. Please see the scout’s version of the
packet to adjust your explanations accordingly. Thank you
and please tell us what you think about the program when
you have finished with your group!
Answers/Explanations for Required Experiments
1. ROLLER COASTER EXHIBIT
Generally, the scout is required to:
Build a roller coaster consisting of at least six pieces of track. Be sure that the ball reaches the end!
Q: Explain the transfer of energy as the ball moves? Why can’t it move too fast/slow?
How you can help her get to the ‘answer’ (hints or questions to ask):
1. When you ride a roller coaster or see one, what comes first? Then what usually comes next?
Answer: 1st– huge hill, 2nd– flat track, 3rd– loop
2. Which should go last, big loops or small loops?
Answer: Small loops
3. Should the ball always go very fast?
Answer: No! It might fly off the track!
Vocab and concepts to explain and understand!
Potential Energy—energy that is based on position since it is ‘not doing anything’ or ’moving’ but
has ’potential’ because it can be used. This is very important when it
comes to gravity! A ball that is higher up (like the top of the highest
slope) has more potential energy than a ball that is on the ground.
Kinetic Energy—energy based on motion (the opposite of potential energy). Anything that moves
has kinetic energy. The more or the faster something moves, the more
kinetic energy it has.
Transfer of Energy—anything that has energy can change what type of energy it has. For instance, an object resting on top of a hill has potential energy, which
transforms into kinetic energy when it rolls down the hill.
Velocity—a fancy word for speed plus direction (for example: a car is going 60 mph but is it headed
north, south, east, or west?). The velocity of the ball on the track
changes depending on its transfer between potential and kinetic energy.
So, what’s the ‘answer’?
The roller coaster should start with a relatively high slope followed by shorter tracks/hills/loops, then higher
hills/loops/tracks, then finally shorter tracks/hills/loops. The higher pieces give the ball potential energy that
can be converted into kinetic energy (shown by the velocity of the ball). This is a lot of trial and error because
if you have too many short pieces at the beginning the ball will not have enough (kinetic) energy to get to the
end. But on the other hand, if you put too many high pieces at the beginning then the ball has too much kinetic energy and the ball flies off the track! So you need to ‘mediate’ this by building in shorter heights
throughout to give the ball more control (in other words, a chance to use up the kinetic energy). As the ball
flies down the hill, for one moment the potential and kinetic energy are equal to each other.
Answers/Explanations for Required Experiments
2. DAM THE CREEK EXHIBIT
Generally, the scout is required to:
Build a dam that keeps back almost all of the water using as few bricks as possible. Q: What is the
purpose of the drainage channels? Why can’t we hold all the water? How many structure combinations can you come up with?
How you can help her get to the ‘answer’ (hints or questions to ask):
1. Think of a real dam. Is it thicker at the bottom or at the top?
Answer: The bottom
2. Does the dam work better when the bricks are lined up evenly or when they are staggered?
Answer: Staggered
3. Is it possible to hold back all of the water (without breakage)?
Answer: No! See below...
Vocab and concepts to explain and understand!
Staggered Structure—the pieces (or blocks/bricks) do not line up perfectly in rows and columns.
The blocks interlock for increased overall strength.
Drainage Channels—small, narrow openings in the dam that allow water to escape a little bit at a
time.
So, what’s the ‘answer’?
There are many many combinations of bricks but you will find that if you line them up perfectly, the
bricks slip out a little bit anyway and do not stay in their original formation. That is because this
strategy does not evenly distribute the amount of pressure being forced upon the wall by the water.
It is better to stagger the bricks so that the force is better distributed within the thickness of the wall.
(For instance, think of a regular brick wall. Are the bricks lined up perfectly? No, they are designed
to interlock so they don’t fall over as easily!) In addition, you will find that you must allow some of
the water to escape the blockade. If you try to hold it all back, the wall will be destroyed by too much
water pressure. But with the channels or openings you create, you can at least control how much
gets out. By easing the pressure, the dam is more likely to be successful in the long run.
Answers/Explanations for Required Experiments
3. ELECTRICAL CIRCUITS EXHIBIT
Generally, the scout is required to:
Wire a circuit (or ‘plug in wires’) that makes at least two lights shine brightly. Q: What is
necessary to have a complete circuit? What is a circuit? What’s it’s shape? What is the difference
between a series and a parallel circuit?
How you can help her get to the ‘answer’ (hints or questions to ask):
1. What is a circuit?
Answer: A pathway in/on which electricity can travel. It is best to think of it as one big circle.
2. What happens if there is a gap in the circuit?
Answer: The electricity can not flow through it (thus the lights do not come on).
3. Look at the pictures that show the difference between series and parallel circuits. Which is easier
to make because it has less ‘paths’?
Answer: Series.
4. Make each type of circuit according to the pictures. For each circuit, include one bulb and then re
-do it with two bulbs. In which circuit are the bulbs brighter?
Answer: Add more bulbs to the series and they get dimmer. In the parallel circuit, the bulbs remain
just as bright!
Vocab and concepts to explain and understand!
Electricity—it takes the form of energy (which flows outside of the electrical wire) but it can also
mean a charge (which flows inside the wire). When you get down to it, electricity is simply a positive or negative charge that is attracted to the opposite charge
(positive seeks negative and vice versa). Static electricity in the form of lightning is essentially the same as the electricity that we use in our computers and
other such devices.
Electrical Circuit—this is simply the pathway that electricity takes as it travels. In order for electricity to flow through a circuit it must be closed. This means there are no gaps in
the circuit. If the circuit is open then electricity will not go through it. You need a
conductor such as metal (often in the form of copper wiring) in order to make a
circuit. All of the metal in a circuit must be touching each other for it to be
closed. There are several key parts to a circuit: power supply (battery), switch
(like a light switch in your home), load(s) (in this case, light bulbs), and wiring to
connect everything.
Is this circuit open or closed?
It is open! So electricity cannot
flow through it!
Answers/Explanations for Required Experiments
...CONTINUED 3. ELECTRICAL CIRCUITS EXHIBIT
Vocab and concepts to explain and understand!
Series Circuit—
in this type of circuit everything is connected in one big circle.
There is only one path for the electricity to share with all the
parts.
Parallel Circuit—
a more convenient yet more complicated type of circuit than the
series. Instead of one large path/circle, there are multiple
paths. Each bulb should have its own set of wiring.
Amps— measure the rate of the electrical current flowing through a circuit
Volts—measure the push of electrical current flowing through a circuit
So, what’s the ‘answer’?
The parallel circuit should clearly shine brighter than the series circuit. When you add the bulbs to
the series circuit, they are sharing electricity with each other (the same electrical charge has to push
through everything). Thus the bulbs visibly get dimmer. But in the parallel circuit, since each bulb
has its own pathway to the power supply, the bulbs keep their brightness (each gets its own electrical push charging through it). In fact, imagine disconnecting one of the bulbs. The other bulb stays
lit (unlike the series, where any gap at all stops all electricity)!
To have a complete circuit means to have a closed circuit where all the metal parts are connected to
each other and there must be a power supply. However, the power supply must be connected in a
special way! One end must be connected to the positive side (often called a terminal) while the
other end must be connected to the negative side.
Answers/Explanations for Required Experiments
4. PUZZLES & BRAIN TEASERS (3 TABLES OF 4)
Generally, the scout is required to:
Complete at least 4 puzzles. Q: Could you solve each puzzle on your first attempt or did you need to
try different methods? As you solve puzzles, can you find any patterns (write an example)?
How you can help her get to the ‘answer’ (hints or questions to ask):
Since we have 3 tables of puzzles, you/she might have trouble picking out which ones to do! We suggest completing puzzles of different types. You can do this according to perceived level of difficulty
(easy, medium, hard) or problem-solving or math skill.
Below we have listed our puzzles/teasers according to the type of skill that is required along with helpful hints/clues/give-aways in case your scout is having trouble:
Mathematical Operations

Magic Square– the even numbers go in the corners...
Optical Illusions
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Horse & Cowboy—keep turning the cowboys, even if it seemingly makes no sense
If you like these then check out the Hyperbolic Slot Exhibit or the illusions on our walls
(opposite the bathrooms or on the gray wall on the other side of the electrical exhibits)
Assembling Geometric Shapes




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Pyramid Puzzler—the same sides of each piece touch each other (rectangles)
Trapezoids 2 Triangle—each trapezoid is tilted differently...
Tangram—you’re on your own for this one! It takes time to get to know how the shapes
form bigger shapes
Square Deal—in the corners: little square, a triangle, and ‘roof’ of the ‘house’
You can try repeating these activities at the Geometric Shapes Exhibit (table on the carpet
that features various magnetic geometric shapes). Especially Trapezoids 2 Triangle. You
can also challenge them to create a 3-D triangular-base pyramid without looking at the instructions!
Sequential pattern (repeated designs/events) and Algorithms (step by step calculations)


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Tower of Hanoi—move the top disc to its own peg and then the next smallest to its own
peg. Put the smaller on the one you just moved. Now move the third disc onto its own peg.
What now? Move the smallest disc back on the original stack of discs… (algorithm)
Crossing the River— the children are the key: there must always be one on each side– so
if there isn’t? Correct it by taking the other child to the other side...
Army Ants—Move the first ant into the small space then move all 5 remaining ants away
from the side you want to move to...
Spatial Reasoning


Circle Packing—the big red circles are as far away from each other as they can get and
the blue ones are in the center...
Box of Many Holes—start: longest pegs and work your way down to smaller ones...
Matching

Color Match—the very center is made up of 4 yellow dots...
So, what’s the ‘answer’?
The answers/clues can be found above or at the exhibit but as we said before, what matters is the
process and not necessarily the end result. Mathematical exercises are great because people tend to
develop their own strategies for problem-solving. As the girls work, you should encourage them to
come up with their own ‘plans of attack’. We suggest that they write the names of the puzzles that
they plan to solve in their packets and then draw a tick mark next to it for each attempt.
Answers/Explanations for Required Experiments
5. MINIRACERS EXHIBIT (not part of the Daisy program)
Generally, the scout is required to:
Build a K’NEX dragster that races to the finish line. Q: What propels the car forward when you set it
on the track? Identify the forces of the movement. Come up with a design improvement.
How you can help her get to the ‘answer’ (hints or questions to ask):
1. Do you want to make the Sprint Racer or the Gear Head Racer?
Answer: For a simpler design go with Sprint Racer. But the Gear Head makes further use of mechanical advantage with the added gears. Hopefully in your team, you will get the chance to race
the two designs side by side to compare their performances!
2. What is the rubber band for?
Answer: It creates elastic force (see below) that will propel the car forward (as a result of winding it
around the back axle to give it potential energy).
3. Is there anything that can be done to improve the given design?
Answer: Yes! Our car design is prone to breakage (as well as the rubber band itself) due to the excessive force of the rubber band so making the car stronger with more reinforcements or making it
longer helps to relieve the stress. You can also tie the rubber band (a simple loop and pull-through)
so that it doesn’t get in the way of the car when it comes undone. You can do this to the end that’s
at the front of the car and/or on the purple tab on the back axle. Another idea is to use two rubber
bands, either together or each coming from a separate axle outside and away from the wheel.
Super smart vocab and concepts to explain and understand!
Elasticity and Elastic Force— no matter how slight, all substances stretch or compress when a
strong enough force is applied. When a substance can return to
its original form (when force is removed), it’s considered elastic.
This applies to all substances up to a certain ‘elastic limit’. Elastic
force manifests when a relatively elastic substance is trying to return its springiness to its natural state.
Gears—otherwise known as cog wheels, these toothed wheels
are used in machines to transmit motion from one moving part to
another. Friction is reduced by the teeth, which interlock for a
smoother transition and also reduce shifting of parts. While not
typically given official status, gears can be thought of as honorary
members of the simple machines group (they are simply a special
form of the standard wheel & axle). They can help to change the
direction and amount of an applied force, especially if a smaller
gear is connected to a larger gear. The larger wheel requires
more distance for turning but less force.
So, what’s the ‘answer’?
The elastic force and potential energy of the rubber band, created as you
wind it around the back axle of the car, propels the car. It is interesting to
compare the two types of car designs (and even more interesting if your
girl(s) come up with her/their own twists!). Which performs better? On
one hand, the Sprint Racer is simpler with less opportunities for things to go wrong plus it makes it
lighter. On the other hand, the Gear Head might have less work to do depending on the placement
of the gears, thus making use of mechanical advantage. When our staff tries this out, it seems that
one car starts out strong but then the other catches up, making the race just about even!
Answers/Explanations for Elective Experiments
1. CRANK POWER EXHIBIT (not part of the Daisy program)
Generally, the scout is required to:
Work as a team to light up the headlights, make the radio play music, and spin the fans and mixer all at
once. Q: What do generators do? Identify what types of energy are being used and how they transform.
How you can help her get to the ‘answer’ (hints or questions to ask):
1. What’s the first thing that we should do?
Answer: Use the wires (and extra wires) to connect the cranks to the appliances (it’s like completing a
circuit– as mentioned in number 3). The cranks are color-coded to help you understand what is being
connected to what.
2. How can we be sure that everyone is working together and using the cranks properly?
Answer: Everyone must turn the cranks in the same direction.
3. How is this possible?
Answer: There is something called a generator inside the exhibit. When you give it mechanical energy,
it turns that into electrical energy. See vocab and explanations below...
Vocab and concepts to explain and understand!
Crank— a device where an arm or connecting rod is attached to something that rotates (usually at a 90
degree or right angle). This makes it easier to rotate the device.
Mechanical Energy—in a mechanical system, this is the sum of potential and kinetic energy. So for
instance, think of a simple machine like an inclined plane. There is an application of kinetic energy as someone in a wheelchair uses it as a ramp, but the position it provides (lower to higher
height) based on its design also gives us potential energy. So we have an energy based on the
movement itself (kinetic) plus the advantage of using a machine (potential energy).
Electromagnet—just like it sounds, you can use magnetism to produce electricity or the other way
around! Just about every single piece of modern technology relies on electromagnets.
Generator— basically it turns mechanical energy into electrical energy (the opposite of a motor). This
is accomplished with an electromagnet. First, you rotate a coil of wire through a magnetic field.
This creates a voltage (the push of an electric charge) in the wire. Then this voltage/electrical
charge is passed on to be used somewhere else as the wires brush against a couple of rings
(you cannot connect other wires to the rotating wire, that’s why you need the rings). Ta-da! We
have created electricity that can be used to power an electrical device. By the way, as the wires
rotate, the voltage constantly fluctuates. Not every generator works this way exactly, but this is
the basic form.
SEE IMAGES ON THE NEXT PAGE
So, what’s the ‘answer’?
If further or simpler explanation is needed, check out the diagrams and explain to the girls that what you
are using is called a generator because you’re generating electricity from movement. When you turn
the crank you are actually turning electrical wires inside a magnet, which creates electricity inside the
wires! Then the wires brush against rings that pass the electricity to other things that need it to work.
So, from movement, we get electricity!
Answers/Explanations for Elective Experiments
...CONTINUED 1. CRANK POWER EXHIBIT
Electromagnets (these are easy to make at home!)
Generator (very basic design)
Answers/Explanations for Elective Experiments
2. EARTHQUAKE EXHIBIT
Generally, the scout is required to:
Build the biggest building possible that can withstand a very shaky earthquake. Q: What is the key to
building a strong structure? How many levels of blocks can you stack on top of each other (in a 4-wall
structure) without it falling down?
How you can help her get to the ‘answer’ (hints or questions):
1. How can extra support be given to the blocks?
Answer: Insert the dowel rods into the block’s holes to hold them together.
2. is it better to use the rods horizontally or vertically?
Answer: Both!
So, what’s the ‘answer’?
The results depend on what the girls make. But the key is the use of the reinforcing
rods, which provide stability and keep blocks from collapsing. Mention that this concept is used when construction workers are putting together concrete blocks.
3. MAGNETIC SCULPTURE
Generally, the scout is required to:
See how many nuts you can get to stick together. The hex nuts are not originally magnetized. Q:
How can such long chains of nuts be created (what’s the longest one you can make)? Is magnetism
an energy or a force?
How you can help her get to the ‘answer’ (hints or questions to ask):
1. Do the nuts only stick to the horns?
Answer: No! You can build outward farther and farther away and attach the nuts to each other!
2. What is the longest chain of nuts that you can create (with only a few nuts originally attached)?
Answer: A simple chain (built upward or out) is unstable and eventually gravity wins out and the chain
collapses. Our staff can usually only get to 15-17 nuts.
3. What is a force?
Answer: a push or a pull. Whereas energy is the ability to do work.
Super smart vocab and concepts to explain and understand!
Temporary magnet—something that can only take on magnetic properties when it is in the
presence of a magnetic field. It really depends on what you’re using but the best materials for this are magnesium, molybdenum, lithium, tantalum (paramagnetic materials
such as the hex nuts). Once the magnetic field is taken away, the material is no longer
magnetic. Theoretically, the material is magnetized because the atoms inside it line up
like a bunch of mini-magnets with their ends going in the same direction. These groups
of atoms form domains.
Permanent magnet— a magnet that holds its magnetic properties for a very long time. The materials that can
become permanent magnets are called ferromagnetic and are usually combined together in alloys
(mixtures): iron, cobalt, nickel, and sometimes steel.
So, what’s the ‘answer’?
Each horn is the pole or ‘end’ of a very strong magnet. Since the nuts are paramagnetic, they have the ability
to become temporary magnets. But once they are pulled too far away from the magnetic field of the poles, they
no longer have that property. *Magnetism is a force. Interested in magnetic fields? Check out our magnet exhibits right next to you! Notice that the nuts stick together if they are close to the horns– responding to the magnetic field.
Answers/Explanations for Elective Experiments
4. FLIGHT DECK (not part of the Daisy program)
Generally, the scout is required to:
Make a paper airplane that flies through at least one hoop. Q: What are the four forces that must be
considered to make something fly? Are these forces balanced while the plane is flying? Find the
‘center’ of the plane in terms of the force that is trying to pull it down.
How you can help her get to the ‘answer’ (hints or questions to ask):
1. What force gets the plane started?
Answer: You! Well, thrust: you ‘thrust’ the plane forward. This is force number one.
2. What force tries to bring the plane down (and all things on earth)?
Answer: Gravity! Force number two! Actually the term is ‘weight,’ because that is the effect of gravity
that we experience. You can find the center of gravity by finding its balancing point (see last section).
3. If gravity is constantly trying to pull the plane down, what could possibly be keeping it up in the air?
Answer: Lift (see below)! Another way to answer is by saying, the design of the plane (see next…)
4. Why is your plane narrow in the front and so wide in the back?
Answer: Like a boat pushing through water or a knife slicing through butter, your plane needs to push
through air as it moves. So the front shape helps it move faster and more easily. But why isn’t it like
that all the way through (like a spear)? To create lift, we need to create a difference between the air
above and the air below the plane…(see below)…, which is why the back must be wider.
The four forces
Super smart vocab and concepts to explain and understand!
Thrust— the force that pushes a plane forward. For a paper airplane, this is your arm. For a real airplane this is the propulsion resulting from the burning of the fuel that pushes out the back.
Drag— the force that pushes the plane backwards (opposite of thrust). The air that the plane is pushing into, pushes back—’air resistance’. This is why we want our planes to have some weigh
to them.
Weight— the force of gravity that pushes the plane down. So, this might lead us to make the plane
as light as possible, right? Not necessarily...if it’s too light, it won’t be able to counteract
drag. All planes have a ‘center of gravity,’ which surprisingly is not exactly in the center– it’s
mostly centered but more towards the front of the plane. This helps guide the plane through
wind. The same is true for homemade model/paper/bottle rockets as well.
Answers/Explanations for Elective Experiments
… CONTINUED
4. FLIGHT DECK
Lift— the force that counteracts weight and pushes the plane upwards– all because of the movement
of air. If you look at a wing of a plane from the side as it moves, there is air flowing above it
and below it. Because of the curve of the wing, the above air has more distance to cover to
get to the back than the below air. Since both get to the back at the same time, the air
above must move faster. Fast-moving air has less pressure. So, the greater pressure below the wings ‘pushes’ or ‘holds up’ the plane! There is a ‘center of lift’ in the plane, which
is actually behind the center of gravity.
In this diagram, we are looking at the wing
of the plane from the side. Remember, the
air above and the air below are getting to
the back at the same time.
In this diagram of a stable and leveled
flight, CG stands for ‘center of gravity’ and
CL stands for ‘center of lift’. By the way, T
stands for ‘tail load,’ which is a horizontal
stabilizer.
So, what’s the ‘answer’?
The four forces are listed above: thrust, drag, weight, and lift. So a proper design accounts for forces
pushing/pulling at the plane from all sides! But this exhibit is about execution as much as it is about
design. When you fly the plane, you can’t push too hard or the thrust will overcome the drag and the
plane will not fly the way you predict it (so you won’t be able to get it through the loop). The four
forces can’t be too unbalanced, but you still need the thrust to slightly overcome the drag and the lift to
slightly overcome the weight. An interesting way to test your center of gravity is to try to balance the
plane on your finger. The center should be slightly towards the front of the plane. So, when it flies,
the plane should point downwards somewhat. The extra folds in the front should help in this matter.
Also, as shown in the diagram, whatever plane is created, the wings should be flat at the bottom (as
seen from the side) but provide a curvature or some kind of extra distance on top (to create the different air pressures above and below the plane).
Answers/Explanations for Elective Experiments
5. LIGHT & VISION ROOM
Generally, the scout is required to:
Find out what a red image looks like under blue light. Create a purple shadow. Bend some light. Q:
What are the primary colors of light? How is a lens different from a mirror? How is a convex shape
different from a concave shape (you may draw)?
How you can help her get to the ‘answer’ (hints or questions to ask):
1. Where can we find blue light and a red image? How can we make it easier to tell what color the
red has changed into under the blue light?
Answer: Go to the exhibit in the Light Room called Color Change-Up. You can create blue light by
playing with the dials and turning up the blue and turning down the other two light colors. There are
fruit-shaped color foam pieces that can be held under the blue light. Focus on the red apple but notice
that without other ‘colors’ around, it is hard to tell what it has ‘turned into’. We suggest holding up all
of the foam pieces together to get a better understanding of how the blue light has altered the color.
2. When you stand at the exhibit called Colored Shadows, how do you cause the different colors to
appear?
Answer: Your body is splitting up the different colored lights. Simply look behind you: this is accomplished because the bulbs are located at different spots, so that when you stand straight in front of
them, you happen to block some in certain spots. Notice the “purple shadow”…?
3. At the Lenses, Mirrors and Filters table, how are prisms, mirrors, and filters different? In other
words, how do they interact with light?
Answer: Prisms bend and split up light. Some prisms split up light very well into its different parts
(meaning colors), which you can sometimes see as the light shines through the prism and onto the
white wall in the room. Mirrors reflect light, which means they change the direction of light rays (it’s
fun to play with the curved mirrors and look at the reflections on the table!). The filters simply change
the color of light (filtering out the now non-visible parts of light).
Super smart vocab and concepts to explain and understand!
Refraction— this is what lenses and prisms do to light because they sort of let light shine through but
then bend it. All objects that let light shine through them do this to a certain extent (try
the classic experiment: a straw in a glass of water– from the side, the straw appears to
‘bend’ below the surface). Lenses and prisms tend to do this to an extreme. Prisms
bend light so much that the white beam is ‘broken’ into its colorful parts and thus we
see rainbows. The curves of concave and convex lenses do this a little more subtly,
which is helpful in making things look bigger or smaller.
Left: prism breaking up white
light into a rainbow.
Right: a pencil in water is ‘bent’.
Light is angled differently in a
different material: air vs. glass
vs. water.
Answers/Explanations for Elective Experiments
...CONTINUED
5. LIGHT & VISION ROOM
Left: convex lens
Right: concave lens
Reflection— mirrors change the direction of light rays. In a straight mirror, images are exact copies,
except backwards. But like lenses, you have concave and convex mirrors, which can
make things seem bigger or smaller depending on how the curves direct the rays.
Left: convex mirror
Right: concave mirror
So, what’s the ‘answer’?
Under blue light (at the Color Change-Up exhibit), the red apple should appear to be a dark purple.
When you’re at the Colored Shadows exhibit, you create a ‘purple (or magenta) shadow’ as your body
blocks off the green light in certain spots– thus allowing the red and blue to mix and make purple. So
as you stand staring at the wall, the magenta shadow should be in the middle, the cyan on your left
and the yellow on your right. This makes sense because the red is on the right, the green in the middle and the blue on the left.
You might think that mirrors bend light. But they actually cause light to change direction. So, the
bending is done by lenses and prisms.
Finally, if you were to ask the girls, what are the primary colors of light, the might answer with the wellknown primary colors of paint (red, blue, yellow– or as described more accurately below, magenta,
yellow and cyan). Many a time spent painting things in elementary school teaches us that mixing up
all the colors gives us black and having no color means white. The trick is that light is the opposite:
white means all the lights are mixed together (as demonstrated by the shadows wall, the color mixing
with the dials and the prism at the table) and black is a complete lack of light. As can be observed by
playing with Color Change-Up and Colored Shadows (just look at the 3 bulbs), the primary colors of
light are red, blue and GREEN (not yellow).
The Einstein Illusion is based on your assumption (and your subconscious learning) that all human
faces are convex (since in real life they are).
The Infinity Mirror has only two mirrors with one real one in the back but a special mirror in the front
that is half-reflective and actually lets some light pass through (like the colored lights in between the
two mirrors). Since a little bit of light is released each time a reflection goes from one mirror to the
next, it repeats in an infinite-looking cycle.
Left: primary colors of
light
Right: primary colors
of paint
Answers/Explanations for Elective Experiments
6. MECHANICAL ADVANTAGE EXHIBIT
Generally, the scout is required to:
Try to lift each 100 pound stack of weights.* Q: Which system of pulleys makes it easiest to lift
100 pounds? With which is it hardest? Which ones require you to pull the most rope? Which
requires the least amount of rope? How much force (in pounds) is needed to lift each rope?
What is the trade-off that happens when we make work easier by using a simple machine?
*Adult cooperation required for heaviest pulleys (the two on the right, with the least wheels).
How you can help her get to the ‘answer’ (hints or questions to ask):
1. What do you notice about the pulley that has the most wheels?
Answer: It is the easiest!
2. What do you notice about the pulley where you pull the most rope?
Answer: It is the easiest and has the most wheels!
3. Look at the pulley system with two wheels. What is the difference between the wheels when
the weight is lifted (by an adult)?
Answer: The bottom wheel moves along with the weight while the top wheel remains still. Also,
notice that both wheels are not ‘in place’ until you pull on the rope and then they are jolted upright.
4. If the pulley with one wheel requires 100 pounds of force when you pull on it, how many
pounds of force are required for the pulley with two wheels?
Answer: 50! Because there are twice as many wheels, now you only need half as much force
(the force is distributed evenly between the wheels). The same division concept applies to the
others…
5. Why is there a wheel? Why not just pull rope from a rod or piece of wood?
Answer: Wheels reduce friction, making the pulling easier. Without them, we would be continuously rubbing the rope against a rough surface, which would cause it to rip and tear in the end.
Super smart vocab and concepts to explain and understand!
Mechanical Advantage—simple machines like pulleys provide mechanical advantage because
they make work easier through simple trade-offs. For instance, in exchange for using less
force to move something, we add distance or we can change the direction of the applied
force. For instance, note that as we pull down on the rope of the pulley, the wheel pulls the
weight up.
Simple Machine—a machine with one or two parts that makes work easier. A pulley is just one
example, the others are: levers, inclined planes, wheel and axle, screw, and wedge
(sometimes gears are included). Inclined planes are similar to pulleys in that it is easy to
see that by adding more distance (a longer ramp or more rope to pull), we need to use less
force to accomplish work.
Work—the result of unbalanced force moving an object (measure in terms of distance).
Power—the amount of time taken to do work (so greater power, means the work was done in a
shorter time period).
Answers/Explanations for Elective Experiments
...CONTINUED
6. MECHANICAL ADVANTAGE EXHIBIT
So, what’s the ‘answer’?
The pulley system with 6 ‘wheels’ is clearly the winner, requiring only 16.6 pounds of force! The pulley with 4 wheels is next, requiring 25 pounds for force. Next is the pulley with 2 wheels which requires 50 pounds of force. Finally the single-wheeled pulley requires all 100 pounds of force. Technically the single-wheel is still a simple machine, so you would think that it would provide more mechanical advantage. Well, it’s definitely easier than just trying to grab the weights with your hands
and the wheel does reduce the friction of the lifting. Notice the trade-off: the easiest pulleys to lift
also require more rope to pull. So in exchange for using less force, we added distance.
Here’s an interesting thought/question to share: what if the single pulley were upside down? See
the pictures below. The answer is surprising! The amount of force needed is cut in half! Why? Because the other end of the rope needs to be attached to the ceiling (or something similar), you actually have two upward pulling forces (you share your upward pulling force with the ceiling)! We can
actually take this further by doing the same thing with pulleys that have more wheels.
Fixed pulley
Movable pulley
Combined pulley
7. PARACHUTE LAUNCH EXHIBIT
Generally, the scout is required to:
Propel a paratrooper up to the ceiling. Q:How do parachutes slow the descent of a person or object?
How you can help her get to the ‘answer’ (hints or questions to ask):
1. What if we used pillows instead of a parachute?
Answer: It wouldn’t work! Even though a pillow is light, it does not have the correct shape.
2. What if we used a long, wide and thin piece of hard plastic instead of a parachute?
Answer: It wouldn’t work as well as a parachute. Now, you’ve got the shape and concept but the
piece of plastic would not capture as much air and it would not be very controllable. It would slow
you down a little bit but you might spin around and fly about out of control.
3. What is more important about the parachute: the material or the shape?
Answer: If you had to pick one, you might go with shape. But if you were up really high you would
need special material that does not tear and can be controlled and deploys properly.
Super smart vocab and concepts to explain and understand!
Friction—a force that tends to stop or resist motion. This happens when solid surfaces rub against
each other but also relates to air friction/resistance of objects that fly or fall through the air.
So, what’s the ‘answer’?
When the parachute opens, it catches air. This air resistance acts against the force of gravity to decrease the speed of the fall. A parachute needs a large surface area since larger objects resist
changes in motion more than smaller objects. The larger the object, the more air resistance. Some
parachutes have holes deliberately added to relieve pressure, prevent tearing and help steering!