SCIENCE DEMONSTRATIONS
(PERFORMED IN COLLEGE)
PHYSICS
WACKY WHISTLE
AIM- To make a water whistle
REQIREMENTS: Beaker, Water, Straw,
Scissors.
PROCEDURE:
1.
Using scissors, about 1/3 of the way down the straw, partially
cut through the straw. The cut should be almost all the way through the straw
but leave a small piece uncut to keep the two straw sections attached.
2.
Bend the straw into a right angle at the cut, but be
care full not to break the straw segments apart.
3.
Fill a cup or glass ¾ full with water.
4.
Slide the longer section of straw into the water
5.
Keep the straw at a 90⁰ angle. Place your lips on a shorter end of the
straw and blow with a light, constant breath.
6.
Try to raise and lower the straw in the water. Check
the pitch of water whistle.
OBSERVATION: Whistling sound is produced
inside water and the pitch is high. And when it is removed out the pitch is
very low.
EXPLANATION: Waterwhistle works through
vibration of air itself and, more specifically, the column of air inside the
straw. The longer segment of straw that is partially submerged in water is full
of air and water. When you blow the air across the top of the longer straw
segment, you are causing the column of air to vibrate.
The vibrating
column of air creates the whistling sound which you hear. The pitch of the
whistling is dependent on how much air you allowed to be inside the straw. The
more air that is inside the straw, the lower the pitch of the whistle less air
is going to create a higher pitch.
CHEMISTRY
CLOUD IN A BEAKER
AIM: To study formation of
clouds
REQUIREMENTS: Beaker, Ice Bag, Hot Water, Matches.
PROCEDURE:1. Fill one third of the
beaker with hot water.
2.
Light the match and hold it over the jar opening.
3. After a few seconds, drop
the match into the jar and cover the top of the jar with the bag of ice.
OBSERVATION: Little cloud form inside the beaker.
EXPLANATION:The warm water heats the layer of air that it touches. Some
of the water evaporates into the air forming water vapor. The warm air
containing water vapor rises, and then cools, as it comes in contact with the
air cooled by the ice. When the water molecules cool, they slow down and stick
together more readily. The particles of smoke act as nuclei for the bunches of
water molecules to collect on. This process is called condensation.
BIOLOGY
MODIFICATION OF LEAVES
AIM: TO STUDY
MODIFICATION OF LEAVES
REQIREMENTS: Cactus,
Water Hyacinth, Onion, Aloe, Bougainvillea, Pineapple Leaves, Bryophyllum Leaf.
EXPLANATION: Leaves are
often modified to perform functions other than photosynthesis. They perform
various functions like Protection, Buoyancy, Storage, Attraction Reproduction,
Absorption.
CACTUS- cacti have lost true leaves, retaining only spines which are
highly modified leaves. Spines help prevent water loss by reducing air flow
close to the cactus. It helps in defending against herbivores. In absence of
leaves, enlarged stems carry out photosynthesis.
WATER HYCINTH- the leaves are 10- 20 cm across on a stem which is
floating by means of a buoyant bulk like nodules at its base above the water
surface. They have long spongy and bulbous stalks.
ONION- Onion has fleshy modified scales envelop a central bud at the tip
of the stem. They belong to xerophytic habitat. They have water storage tissue.
These helps plants to conserve very limited supply of water and resist
desiccation (drying up).
ALOEVERA AND PINEAPPLE: Spines develop on the margin as at the apex.
BOUGANVILLEA: The actual flower is very small and generally white but
each cluster of three flowers is surrounded by three or six bracts with bright
colors associated with the plant, including pink, magenta, purple, red, orange,
white or yellow.
BRYOPHYLLUM - Plantlets or buds grow along the notches, bases, apices
and tips of blades and petioles.
(PERFORMED IN SCHOOL)
SCIENCE DEMONSTRATIONS
School : Saraswat
Vidyalaya Mapusa Goa
Physics
Wacky whitsle, atmospheric pressure in a bottle
Chemistry
Lava lamp, Thirsty candle, Snow in a bottle
Biology
Modification of leaves, Types of leaf apex
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