Scratch Robots
Catapult
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Catapult – Step 1
Parts:
- 8.5” x 11” cardboard
- 4”x6” Foamie
- 1 Starbucks straw
- 4 Starbucks coffee
stirrer sticks
- Paper clip
- 8” string
Tools:
-
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Scissors
Ruler
Tape
Hot Glue Gun
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Catapult – Step 2
Base:
Cut the cardboard
base and strengthen
it by hot gluing
coffee stirrer sticks.
Each line on the green
mat is 1” square.
Therefore the base is
3” x 5”.
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Catapult – Step 3
Arm parts and rubber
band stops.
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Catapult – Step 4
Base rubber band
stops:
Hot glue foam strips
on the middle coffee
stirrer stick on the
base.
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Catapult – Step 5
Arm-1:
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1.
Cut the rubber
band strips and
hinge parts.
2.
Hot glue half of
hinge on arm stick.
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Catapult – Step 6
Arm-2:
Hot glue the 2nd half of
the hinge on the arm.
Measure and mark the
middle of the base.
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Catapult – Step 7
Arm-3:
Hot glue arm hinges on
the base.
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Catapult – Step 8
Arm-4:
Hot glue the rubber
band strip on the arm.
It should be positioned
so it aligns with the
rubber band strip on
the base coffee stirrer
stick
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Catapult – Step 9
Rubber bands.
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1.
One rubber band
will act as the arm
spring.
2.
The other rubber
band will act as the
arm stop to control
the throwing
trajectory.
3.
You can twist the
rubber bands to
control the spring
strength and arm
stop position.
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Catapult – Step 10
Hand-1:
Collect these parts to
start the catapult hand
(or bucket).
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Catapult – Step 11
1)
2)
3)
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Hand-2:
1.
Cut a slit in the top
of the hand
2.
Overlap the slit
sides to make a
pocket. Hot glue.
3.
Hot glue the foam
piece so it wraps
around the straw.
4.
Slip the straw hand
over the coffee
stirrer stick arm.
Tape it to the arm.
5.
Experiment with
arm/hand length.
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Catapult – Finished!!!!!!
Catapult Trigger
1. Attach a string to
pull the paper clip
and release the
catapult arm.
2. Hold the catapult
arm down to the
middle coffee
stirrer stick with
paper clip that has
been opened.
3. Tape the base
coffee stirrer sticks
to a platform. This
will keep the
catapult stable.
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