Experiment
Experiment
1: Light travels in straight lines
When you turn on a torch, it produces a ray
of light which travels in a straight line. In this experiment study how
light travels only in straight lines.
Materials:
·
Work Surface
·
Thin A4 Card (Any Colour)
·
Scissors
·
Modeling Clay or Sticky Tack
·
Torch
·
Small Mirror
Methods:
1.
Carefully cut a piece of A4 card in half
2.
Hold the pieces together and cut a slot 5cm
deep in one of the long edges
3.
Stand one of the pieces of card on its
slotted edge.
4.
Support it with four pieces of sticky tack or
modeling clay near the corners.
5.
Stand the other piece of card on its slotted
edge parallel to the first piece and about 15 cm away from it.
6.
Support it with four pieces of modeling clay.
7.
The slots in the cards should be roughly
opposite each other.
8.
Switch off the lights or close the curtains
to make the room dark.
9.
Shine a torch through one of the slots from
about 10cm away.
10. Move the torch from side
to side to make the ray pass through both slots.
11. Replace one piece of card
with a mirror, with its reflecting side facing the remaining card.
12. Shine the torch through
the slot towards the mirror.
General Safety Tip
Be careful when handling sharp objects such
as scissors. Make sure the sharp objects ‘point-away’ from your body. Have an
adult nearby when you do this experiment.
Mirrors can have sharp edges, especially when
broken. Be careful when using them.
Useful
Links
http://www.youtube.com/watch?v=WrQsq8s8XzU
Objective:
We are going to find out which type
of sponge holds the most water.
Research
Questions:
Materials:
Experimental
Procedure
Experiment 2: Sunlight
Plants
need food and water or they will wilt and die. Because plants cannot move
around, they need to grow in a place where they can get sunlight, water and
air. If a plant is growing in a dark, shady place, it will work very hard to
grow towards the Sun because without sunlight, a plant cannot make food. Study
the growth of plants towards sunlight by using another plant without sunlight
as a control.
Materials:
·
A shoe box with lid
·
Some card
·
Sticky Tape
·
Scissors
·
A potato that has ‘eyes’ or buds, from which
a shoot will grow.
Methods:
1.
Make a small hole in one end of the shoe box,
just big enough to let in a little light. Cut three strips of card a bit
shorter than the width of the box.
2.
Turn back one end of each strip to make a
flap. Tape the flaps to the sides of the box.
3.
Put the potato at the other end of the box
from the hole you have cut, and put on the lid. Place the box in a well-lit,
airy position.
4.
The potato is full of stored food, so the new
plant doesn’t need soil or water to start growing. After a few days, the potato
will start to grow a shoot. The shoot will bend its way through the maze
towards the light.
What’s happening?
As
shown in this experiment, if you plant a bean upside down in soil, the shoots will always find
their way towards the light, even if it means they have to wind their way
around other things. Sunlight is essential for a plant’s survival. This is
because plants use sunlight to make food in a process called photosynthesis.
Green leaves use energy from the Sun to make food from water and from a gas in
the air called carbon dioxide. The food, called glucose, is carried through
tubes to the rest of the plant. In the final stage of photosynthesis, oxygen is
released into the air.
General Safety Tip
Be careful when handling sharp objects such
as scissors. Make sure the sharp objects ‘point-away’ from your body. Have an
adult nearby when you do this experiment.
Useful Links
Experiment 3 :Which
Type of Sponge Holds the Most Water?
Objective:
We are going to find out which type
of sponge holds the most water.
Research
Questions:
What factors determine how much water a sponge will hold?
Sponges are useful for cleaning as it holds moisture. They are porous,
which means they have tiny holes in them that allow cleaning fluid or water to
be held. This does the cleaning job much more quickly than you bare hands or
even a wash cloth.
Materials:
Choose sponges of relatively the same size
Natural Sponges
·
Cellulose
·
Sea
Sponge
Artificial Sponges
·
Polyurethane
·
Polyether
(those rainbow packs)
·
Polyester
Water
Large Bowl(s)
Measuring Beaker
Experimental
Procedure
1.
Take
one sponge and press it inside a bowl full of water. Let it drain a little.
2.
Squeeze
the sponge until all of the water comes out in a measuring beaker. Record this
measurement.
3.
Do
the same for all the other sponges.
4.
Evaluate
which one held the most water.
5.
Examine
and compare the sponges and try to understand what properties might help one
hold more water than another.
*Note: You may want to repeat this experiment for a few trials to be
accurate.*
Suggested Chart
Amount of Water Held
MATERIAL
|
Trial #1
|
Trial
#2
|
Trial
#3
|
|
NATURAL SPONGES
|
Cellulose
|
|||
Sea Sponge
|
||||
ARTIFICIAL SPONGES
|
Polyurethane
|
|||
Polyether
|
||||
Polyester
|
Terms/Concepts: Sponge;
Porosity; Absorbency
References:
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