COOL SCIENCE
www.coolscience.org
CARDBOARD
BOAT
RACE!
Objective:
To build a boat out of ONLY cardboard and packing tape that is capable of holding two people, and
can be launched and paddled across a pool.
Details on the event:
WHO can participate?
Anybody! The age categories are as follows:
PRIZES!
In each age category:
‰ First Place – Two Capsela Power Start 175
‰ Second Place – Two $5 gift certificates to
Josh and John’s Ice Cream
‰ All Who Enter – Cool Science Neon
colored Pencil! (WOW!)
First Mate: Ages 7 to 9
Skipper: Ages 10-12
Admiral: Ages 13 to 103
WHEN will the race be held?
Thursday, May 26th, 6pm to 8pm
WHERE will the race be held?
Southeast YMCA
2190 Jetwing Dr, Colorado Springs, CO
80916, 719-622-9622
http://southeast.ppymca.org/
Judging Parameters:
Design and Construction (15 points possible)
Boat Design
Aesthetic Design
Quality of Construction
Flotation and Steering (50 points possible)
Boat Floats when put in water
Boat Floats with one member of team
Boat Floats with two members of team
Boat successfully negotiates pool’s length
(¼= 10 pts, ½ = 20 pts, ¾= 35 pts, all the way = 45 pts)
Speed (35 points possible)
Your time(s)
X 35
Fastest time(s)
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Points
5
5
5
1
2
2
45
35
Design Parameters:
Boats will be subject to a technical inspection the day of the race and must follow these guidelines.
Any boat or team not following these guidelines will be disqualified.
1. All occupants of a boat must wear life vests, and must wear them properly – a team with an
individual not wearing a life vest properly will be disqualified. Life vests will be provided by the
Southeast YMCA, unless you would like to bring your own.
2. The boat will consist of only cardboard and packing tape (Clear plastic tape). Any other
materials are not allowed.
3. Rafts are not allowed! (Swimming on a cardboard surfboard is not allowed.)
4. Boats can be propelled by oars (oars will be provided).
5. The maximum length of your boat is 7 feet. The maximum height of your boat is 3 feet.
6. NO appendages are allowed in the water. No arms or legs may be in the water to assist with
stability or propulsion.
7. The passengers of your boat may not be enclosed above the shoulders of the occupants.
Both people must be visible while the boat is in the water.
8. To qualify as a finisher, both teammates must be in the boat at the end of the race. Time is
called when the boat finishes the race by touching the side of the pool.
9. Racers must be sitting or kneeling. Lying on your back or stomach is not allowed.
10. Each team must remove their entire boat and boat remains from the water after you are
finished and dispose of the boat as requested by race officials.
Suggestions for how to proceed:
Step One: L earn about water displacement and flotation – try the following three activities:
Activity # 1: Water Displacement
Materials needed:
‰ 1 clear plastic disposable cup
‰ 1 empty film canister
‰ 14 pennies
Procedure:
1. Fill a disposable clear plastic cup about half-full with water. Mark the level on the outside of the
cup with either a permanent marker or a piece of tape.
2. Put an empty film canister with the lid on into the beaker of water without splashing the water.
What happens to the film canister? What happens to the water?
3. Remove the canister and add 2 pennies. Then close the lid and observe carefully as you place it
into the water. Mark the new level of the water in the cup. Observe where the level of the water is
on the film canister.
4. Keep repeating step 3, adding 2 more pennies each time until your “boat” sinks. What are your
observations? What happens to a liquid when things float?
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Activity #2 Does it Float?
Materials Needed:
‰ Sink filled with water, or a bucket of water
‰ Submergible (ask a parent) objects from around the house (for example, a wooden pencil, a
cork, a penny, bar of soap, metal spoon, plastic spoon, plastic bowl, toothbrush, etc….)
Procedure:
1. One at a time, place the objects you have gathered into the water. Do they sink or float?
Does anything surprise you?
2. Can you make something heavy, like a ceramic bowl float? (Be sure to have a parent help
you with this.) Why do you think it does or does not float?
Activity # 3 Build a Boat
Materials needed:
‰ Sink filled with water or a bucket of water
‰ Aluminum Foil
‰ Lots of pennies
Procedure:
1. Place a square of aluminum foil onto the water – what happens?
2. Take a small piece of aluminum foil and crush it into the TINIEST ball you can make and place it
onto the water – what happens?
3. Form a small box with the aluminum foil – again, place it onto the water. What happens?
4. Add one or two pennies as passengers to your boat. Does it still float? How many pennies will it
hold? What happens to the foil as you add more pennies – make careful observations! What
happens to the water line on the outside of the boat as pennies are added? Is it even all the way
around? What “fails” first?
5. Redesign your boat to prevent the failure that sunk your boat the first time. How many Penny
passengers can it hold now? Did your boat support more weight?
6. If you doubled the size of your boat, do you think it would hold more weight?
7. Why do you think your boat floats?
8. Imagine yourself as a passenger on this boat. Do you think it would be easy to steer? Try to
redesign your boat so that it will be easy to steer. How many pennies can it hold now?
Step Two: Research! Read the paragraph below to start to understand more about buoyancy and
flotation. Then… do some research on the internet to find out more! Here are a couple of internet
sites to try:
http://www.pbs.org/wgbh/nova/lasalle/buoybasics.html
http://hyperphysics.phy-astr.gsu.edu/hbase/pbuoy.html
The Archimedes Principle: Archimedes is credited with discovering that the buoyant force on an
object is equal to the weight of the displaced fluid. Sound complicated? It’s not as bad as you think!
Archimedes is said to have discovered this principle in his bath while trying to think of a way to
determine whether the king's new crown was gold or a fake. He noticed that as he got into the bath,
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the water level rose, and as he got out, the water level fell. Legend has it he was so excited about his
discovery that he ran naked through the streets shouting, "Eureka!”
Probably everyone has experienced the Archimedes principle – for example, it is much easier to lift
someone if you are both standing in a swimming pool than if you were to lift that same person while
you are both standing on land. Water provides partial support for any object placed in it; this is
buoyancy.
Buoyancy is different for every liquid. For example, the same object, a hard boiled egg, will sink in
fresh water, but float in salt water! Think something very heavy couldn’t float? A steel ball will float in
a pool of mercury! Mercury has much more buoyant force than water does.
Stated another way, an object floats on a fluid if its density (mass per unit volume) is less than that of
the fluid. For example, an unopened can of Diet Soda will float on water, because its density is slightly
less than water. However, an unopened can of Regular Soda will sink in water because its density is
slightly higher than water (due to the sugar!). Another example is that of a fish - under normal
conditions, the average density of a fish is slightly higher than the density of the water he is swimming
in. This being the case, the fish should sink to the bottom. However, fish have an internal way of
adjusting their own density – an internal air bag. If a fish wishes to move higher in the water, it allows its
air bag to expand, if it wishes to go lower, it contracts the bag. An enormous steel supertanker loaded
with cargo (think HEAVY) floats in water – how does it do that?
Step Three: Make a design for your cardboard boat. Draw your design on paper, or talk about it with
your partner. As you design your boat, think about the following: how will you make sure that your
boat can support the weight that it will hold, how you will steer the boat, will you be able to transport
the boat to the pool on race day? How can you make it faster; what causes drag in the water?
Finally, make sure you follow the design parameters on page 2!
Extra Cool! Calculate whether your boat will float! To do this you need to calculate the weight
of the volume of water your boat will displace.
1. First, you need to calculate the volume of your boat. This may sound hard, but if you
can think about your boat as several geometric shapes put together, such as a cube
plus a wedge, it will be easy! You may need an adult’s help with this one.
2. Next, you need to multiply the volume of your boat by the weight of water. Water
weighs 62 pounds per cubic foot, or 0.0359 pounds per cubic inch, or 8.34 pounds per
gallon. Make sure that you multiply the volume of your boat by the correct units! If you
calculated the volume of your boat in cubic inches, make sure to use the cubic inch
weight of water. This website may come in handy: www.onlineconversion.com
3. Now you have a number of pounds of water that your boat will displace. However! If
you put this many pounds in your boat, the water line will be at the top of your boat,
and you had better hope for no waves. So, now use an engineering factor (or “fudge
factor”) to make sure that your boat will float! Divide the number of pounds by 2!
Step Four: Build your boat. Some things that may come in handy for building your boat:
‰ Remember that you can use only packing tape and cardboard!
‰ You may want to have an adult help you use a box cutter to cut the cardboard.
SEE YOU ON RACE DAY!
HAPPY ENGINEERING, AND GOOD LUCK!
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