Spiny Leaf Insects
Materials: Spiny Leaf Insects
Digital Microscopes
Method: Very carefully let the spiny leaf
insect crawl up your hand and arm.
Be very careful of their claws that
will cling. Don’t pull the insect off you or you will damage its claws.
Have a close up look through the
microscope.
Purpose: To learn about the needs of animals.
To become familiar with the
technology of the digital microscopes.
Science knowledge: Read the sheet on display about
phasmids. They are fascinating creatures.
Bubble Snake
Maker.
Materials: Bottles with the end removed.
A piece of towel.
A rubber band.
Dishwashing liquid slightly diluted.
Food colouring
Method: Place the piece of towel over the
open end of the bottle.
Secure with a rubber band.
Drip some food colouring on the end
of the towel.
Dip in the dishwashing liquid.
Blow!!!
Science knowledge:
Bubbles form because of the surface
tension of water. Hydrogen atoms in one water molecule are attracted to oxygen
atoms in other water molecules. They like each other so much, they cling
together. So why are bubbles round? The physicists will tell you that bubbles
enclose the maximum volume of air in the minimum amount of bubble solution, so
that's why they are always round.
When you blow air through your Bubble
Snake maker, you are creating hundreds of tiny bubbles. As the air wiggles
through the fabric, bubbles are continuously being made. The bubbles attach to
each other when they come out of the fabric. It's all thanks to the same
hydrogen bonds that make bubbles.
Tin Foil Boats
Materials:
Tin foil
Some metal washers.
Method: 1.Cut a piece of tin foil. 15
x 15 cm
2. Fold up the sides of the boat
so it will not sink and hold a cargo of
washers.
3. Place the boat in the tub of
water. Begin adding washers for the boat's cargo.
4. See how many washers your boat can
carry before it sinks.
5. Be sure to dry the washers before
you begin adding them as cargo because remember water has weight!
6. Try different ways to distribute
the weight of the washers on your boat so you can carry the maximum number.
Scientific knowledge:
There are two primary forces acting
on this science experiment. The first force is gravity. Gravity is trying to
pull the tin foil and washers downward. The force of buoyancy is pushing the
boat toward the surface.
The gravitational force is determined
by the weight of the alfoil and the weight of the washers in the boat. The
force of buoyancy is the weight of the water displaced by the boat.
Your boat will continue to float as
long as the force of buoyancy is greater than the force of gravity and you do
not overload the boat so it will tip over or leak
Make a Planet
Materials: One ball of ice. (made previously
with a balloon.)
Salt
Food colouring.
Method: Cover the surface of the ice ball
with salt.
Watch the ice melt around the salt.
Drip some food colouring on to it.
Scientific knowledge:
Salt lowers the freezing/melting
point of water.
Ice forms when the temperature of
water reaches 0 degrees Celsius.
When you add salt, that temperature
drops: A 10-percent salt solution freezes at -6 C, and a 20-percent solution
freezes at -16 C.
In very cold countries, salt is used
on roadways to melt the ice. The salt dissolves into the liquid water in the
ice and lowers its freezing point.
Air Pressure
Materials: One glass
One piece of cardboard.
Method: Fill the glass with water.
Place a piece of cardboard over the
top of the glass.
Hold the cardboard in place with your
hand.
Hold the glass over the tub and
carefully turn it over.
Does the cardboard fall off?
Scientific knowledge:
The water inside the cup is lighter
than the air outside, the card is held in place by the air pushing up, while
the force of the water pushing down is less than the air pressure.
Drops on a Coin
Materials: One 5 cent coin.
A cup of water.
A dropper.
Method: Wash and rinse the coin in tap water.
Dry it completely with a paper towel.
Place the coin on a flat surface. The flatter the surface is, the better this
experiment is going to go.
Use an eyedropper to draw water and,
carefully, drop individual drops of water onto the flat surface of the coin.
Keep track of the water drops as you
add them, one at a time, until water runs over the edge of the coin. You’ll
probably be surprised by the number of drops you get on there.
Scientific Knowledge:
There are two properties at work in
this experiment: cohesion and surface tension. Cohesion is the attraction of
like molecules to one another. In this case, the like molecules are the H20
molecules in the water drops. Surface tension is a special term we use to
describe the cohesion between water molecules.
The cohesion and surface tension of
water becomes apparent when the drops of water you add to the coin reach the coin’s
edge. Once the water has reached the edge, you begin to see a bubble or dome of
water forming on top of the coin. The bubble shape is a result of the water
molecules clinging to one another in an optimal shape (just like the bonds on
the surface of a blown bubble).
Dancing Grapes
Materials: A glass and some water
Bi carb soda
Vinegar
Some grapes and sultanas
Method: Fill your glass with water to
between 1/2 to 2/3 full.
Tip in about two teaspoons of baking powder
and stir it thoroughly to dissolve it.
Now slowly pour in about 1/3 of a cup
of vinegar. The mixture will start to fizz and if it looks like overflowing,
stop pouring until it settles down again. Now drop in 3 grapes and 3 sultanas.
The grapes should start to dance
straight away. The sultanas may take a bit longer.
Scientific knowledge:
First, the bubbles are being made by
a chemical reaction between acetic acid in the vinegar and the baking soda.
This produces carbon dioxide gas.
Secondly, there are the bouncing
grapes and sultanas.
When you first put the sultanas into
the baking soda and water, they sink because they are heavier than the water
around them. When you add vinegar, the chemical reaction produces lots of
bubbles of carbon dioxide gas, and some of these bubbles stick to the outside
of the sultanas. Because gas is much lighter than water, these bubbles of
carbon dioxide gas lift the sultanas up to the surface of the water. But when
the sultanas get to the surface, the bubbles of gas burst, so the sultanas
become heavy again and sink.
Materials: Plastic cup
Water (any temperature)
Shaving cream
Cup of water
Dropper
Food colouring
Method: Fill jar about 3/4 full with water
Spray
shaving cream to cover top of water completely.
Drip water on top of the shaving
cream using dropper until it starts to drip through.
Drip food
colouring on top of the shaving cream.
Scientific Knowledge:
When a rain cloud gets so full of
water or mass, the water has to go somewhere and will break through the cloud
and start to fall to the ground. As you pour or drip the water over the shaving
cream cloud, the water will start to break through just a little bit. Observe
your cloud as it gains mass and changes in composition. As the water breaks
through, drip food colouring on top of the cloud.
References
