Here are some ideas to modify the rotocopter design to make it fall more slowly: - Increase the surface area of the blades to create more drag from the air as it falls. Wider or longer blades would work. - Add more blades (4 or 6 instead of 2) to create more drag from more surfaces catching the air. - Make the blades curved or cupped rather than flat to better catch and redirect more air as it falls. - Increase the weight at the center (add a paperclip or washer) to counteract lift from the blades and reduce falling speed. - Change the material of the blades to something less rigid that may flutter more in the air like tissue paper or

3. Place marble inside
Diagram 3
Diagram 2
What You Need:
Scissors
Template
Sticky tape
Marble
Ramp
Diagram 1
What You Do:
Cut out the template
Fold up the template as shown in diagram 1
Use a loop of sticky tape to secure the bottom long flap in place
Place a marble or two into the container you have made – see diagram 2
Fold down the upper long flap and secure in place with another loop of sticky tape – see diagram 3
Construct a ramp by tilting a table or use books and a long piece of thick card
Place the magic bean at the top of the slope in an upright position and let go
Things you could change:
Size of container Things you could observe or measure:
Number of marbles Speed of roll
Mass of marbles Does the bean work or not?
Shape of mass
Material the container is made of
Direction of flips
Ratio of mass to size Number of flips
Colour of bean Sound effect
Gradient of slope
Surface of slope
Length of slope

4. What You Need: What You Do:
1. Using the pencil and ruler, draw 5 squares
• Several different
types of paper arranged in a cross, so that they look like a +
• Scissors sign (make each square about 2.5cm along
• Pencil each side)
• Ruler 2. Cut the cross out
• Bowl of water 3. Fold in the four arms of the cross, so they are
folded on top of the middle square
4. Predict what you think will happen when the
folded cross is placed on the surface of the
water, with the middle square on the bottom
5. Observe the paper closely
Your Task: 6. Explain what you think is happening
List at least 3 7. Repeat with different types of paper
observations 8. Compare what happens
that you noticed 9. Explain why
from the time
that you placed
the paper in the
water
The Science Ideas: What’s Going On Here?
When using photocopy paper the cross will unfold slowly, one square at a time. There are two processes
happening here. The first is capillary action. Paper is made up of tiny fibres of wood, which have small
gaps between them. the surface tension of the water pulls the water into these gaps, so it is absorbed into
the paper. This capillary action leads to the second process. When the paper is folded, some of the gaps
were squashed. As the water filled the gaps, the pressure of the water pushed the gaps back into their
original shape, so the paper straightened out again. When the pressure of a fluid inside an object pushes it
into a certain shape, it is called turgor pressure.
There are many objects whose shape is caused by the pressure of a fluid inside it. A balloon is a simple
example, but many plants are also held up by turgor pressure. The cells of the plants contain water that
pushes out on the walls of the cells. The pressure of the water inside the cells keeps the cells rigid. If a
plant starts to dry out, the pressure inside the cells is reduced, so the cells become less rigid and the plant
starts to droop. This is why many plants go limp if they lack water.

5. Place 12 drops of
water here, repeat
after one minute
Draw a line at the
bottom of all the
points with a
coloured felt pen

6. What You Need: What You Do:
• Jubes or another type
of jelly lolly Using only toothpicks and lollies make a self-supporting
• Toothpicks structure.
Guidelines for building the structure
 This activity can either be done in groups or individually
 Each group should receive a set amount of toothpicks
and lollies
 To finish or win the challenge each group should either
build the tallest structure possible, the structure that can
bear the most weight, a simple structure like a house or
bridge or the structure that most resembles a famous
building, for example the Eiffel Tower.
 A time limit is optional.
The Science Ideas: What’s Going On Here?
What shapes are the strongest?
Square and triangles are very strong shapes. If you use both triangles
and squares in a structure the tower will be more rigid.
Even though the structure appears still, the parts are always pulling
and pushing on each other. Structures remain standing because some
parts are being pulled or stretched and other parts are being pushed or
Applications
The triangle is the strongest shape.
squashed. The parts that are being pulled are in tension. The parts that
Triangles are used to make a very strong are being squashed are in compression.
form called a truss. A truss is a type of Strong structures such as towers, bridges and beams have to be able
frame which is designed to be stiff. to cope with pushing (compressive) and pulling (tensile) forces. For
Before steel, trusses were made of wood example, two bricks side by side can withstand pushing forces, but
or iron. Now they are almost always
made of steel, though some concrete
not pulling forces. A rope can withstand pulling forces but not
trusses exist, and some smaller pushing forces. What shapes can you think of that are strong when
examples use timber. Circles are also you push or pull them?
among the strongest shapes in nature.
External and internal stress distributes Bridges are great example of structures that use simple shapes for
itself evenly throughout a circular
structure. Plant stems and tree trunks are
strength. Triangles form the strongest structure because all three sides
examples of the strength of the circular bear the load. Compression pushes down equally on two sides of the
shape. A bicycle is also an example of a triangle, causing the base to be pulled equally in two directions,
structure that uses simple shapes for which creates tension. In a square, two sides of the structure bear the
strength. The frame of a bicycle is made load.
up of triangles, the frame is tube shaped
and the wheels are circles reinforced Adapted from:
with triangles. This makes the bicycle a http://www.csiro.au/helix/sciencemail
very strong machine.

7. What You Need:
• Small flat white
container
• Water What You Do:
• Blu Tack 1. Place four pieces of Blu Tack evenly
around the edge of the container
• 4 Gobstoppers (4
2. Press a different coloured gobstopper
different colours)
firmly onto each of the pieces of Blu Tack
Gobstoppers
3. Carefully pour water into the container
until the gobstoppers are covered
4. OBSERVE carefully what happens
5. What questions do you have about this
activity?
6. If we changed the …. Would the ….?
7. Could we try….?
8. How could you answer your questions?
9. Think about visiting a library, searching
the internet, or asking an expert
The Science Ideas: What’s Going On Here?
This activity only works with sweets where the colour is embedded in a sugar
coating, because it is the sugar that creates the effect, not the colour. Gravity is the
driving force that spreads the colour. As the sugar (and colour) dissolve, a dense
solution is formed that sinks to the bottom where it is pushed outward by the
solution still falling from above.
When the two colours meet the concentrations are the same, so they stop. After a
much longer period, if you look closely, diffusion will start to cause spreading.
colour

8. What You Need:
• Copy of the Roto-copter
template
• Scissors
• Paper Clips
What You Do:
• Hold the Rot-copter by the
paper clip
• Throw it like a baseball, as
high and far as you can
• You can also stand on a
chair and drop it
Why does the rot-copter spin?
When the roto-copter falls, air pushes
up against the blades, bending them
just a little. When air pushes upwards
on the slanted blade, some of that
thrust becomes a sideways, or
horizontal, push. Why doesn’t the rot-
copter simply move sideways through
the air? That’s because there are two
blades, each getting the same push, but
in opposite directions. The two
opposing thrusts work together to
cause to spin.
Does it fall clockwise or counter
clockwise? Bend the blades in
opposite directions. Now which way
does it spin?
Challenge:
How can you modify the design to make it fall slowly?