Thrust :

                  All aero planes with engines and all rockets depend on thrust. Thrust makes them move forward. They push large amount of air or other gases in one direction. This makes the aircraft fly in the other direction. Now you can see how thrust work in these experiments with balloons.

Things need :

o   Long balloon

o   Heavy paper

o   Tape

o   Felt-tipped pens

Uncontrolled flight :

   v  Use felt-tipped pen to decorate the balloon as an aero plane if you like. It is easier to draw on the   balloon if you blow it up first. Do not tie it shut. Tie it round a matchstick or a pencil.

   v  Cut wings from the heavy paper. Tape them to the Centre top of the plane.

   v  Remove the matchstick or pencil. Blow the balloon up as full as you can. Let it go. Thrust will make it fly around the room in a series of loops and turns until it runs out of air. 

Make the lemon peel dive :

Things need :

    §  Piece of balloon

    §  Lemon peel

    §  Broad mouthed bottle or rubber band

    §  Water

Instruction :

v  Fill the bottle with water till the brim.

v  Put a peel or lemon in the shape of a boat in water.

v  Stretch the piece of balloon on the mouth of the bottle and with the rubber band seal it in place on the mouth of the jar. The balloon should be slightly stretched. It should not sag.

v  Using you finger gently press down on the lid (balloon cover ) and the lemon peel will dive to the bottom of the jar.

v  Release you finger the lemon peel will return to the top of the jar.

Why ?

              The pressure exerted by hand squashes air bubbles in the lemon peel allowing the water. This makes the lemon peel heavy and sink. When the finger is released the air in the lemon peel expands and returns to the top.

Bring the balls together :

Things need :

   §  Ping pong balls

   §  Table

   §  Straw

Instruction :

            ·         Place the ping pong balls a short distance a part on a table.

            ·         Use the straw to blow air between them. The ball move towards each other.

Why ?

                   Air presses on all things. This is called air pressure. When you blow between the ping pong balls, you blow away the air that is between them. This means that air is no longer presses against one side of each ball. But air still presses against the other sides of the balls, and that air pressure pushes the ball together.

Make the paper rise :

Things need :

v  A piece of paper

Instruction :

•    Hold a piece of paper by the corners of edge.
•    Bring it up to your mouth. The paper will droop towards the floor.
•    Blow gently across the top surface of the paper. Does the paper still droop.
•    Take a deep breath and blow harder.
•    The paper rise. Before you blow, the air on both the sides of the paper is still.

§                                                    The pressure is same on both the sides. When you blow over the upper surface, the pressure on the side is reduced. But the pressure underneath is the same as before. The higher pressure underneath forces the paper up. Blowing harder reduces the pressure on the upper surface even more.  This makes the paper rise even higher.

Why water won’t run through the bottle ?

Things need :

            ·         Glass jar with narrow neck

            ·         Funnel

            ·          plasticine

            ·         Screwer

            ·         Water

Instruction :

                 Position a funnel in the neck of the jar.

                 Seal it tightly with plasticine.

                 Fill the funnel with water.

The water cannot flow into the jar. Now  make a hole in the plasticine , the water flow into the jar because the pressure is same inside and outside of the jar.

( i.e ) why you need to make a holes before you can pour liquid from a tin.

Make your own fossil :

Things needed :

             ·         Plasticine

             ·         2 paper cups

             ·         Plaster of paris

             ·         Water

             ·         An object that you would like to use as the fossilized impression

Instructions :

   v  Flatten a ball of plasticine until it is about 2 cm thick while making sure the top is smooth.

   v  Put the plasticine inside the paper cup with the smooth side facing up. Carefully press the object you want to fossilize into the plasticine until it is partially buried.

   v  Carefully remove the object from the plasticine. An impression of the object should be left behind.

   v  Pour half cup of plaster of paris and stir until the mixture is smooth.

   v  Leave it for around 2 minutes.

   v  When the mixture has thickened, pour it on top of the plasticine in the other cup. Leave the mixture until    the plaster has dried.

   v  When the plaster has fully dried, tear away the sides of the paper cup and take out the plasticine and plaster. Keep it in a warm dry place .

Effect of acid rain on rocks :

Things required :

•   Plastic cup
•  Vinegar
•   Water
•  Small piece of lime stone

How it’s react ?

 o   Take a plastic cup. Take half cup of vinegar. ( vinegar is an acid )

 o   Place a small piece of lime stone in the cup of vinegar.

 o   Allow it to soak for several days.

 o   Remove the lime stone and observe carefully.

Why ?

                 In nature when rain water combines with carbon dioxide in air or with carbon dioxide from decaying organic matter , carbonic acid is produced. When the acid flows through cracks in limestone, it chemically reacts with the rock forming dissolved calcium, which is carried away in water.

              

             

Effect of frost in rocks :

Things needed :

                 Two paper cups

                 Freezer

                 Plaster of paris

                 Water

                 Scissors

                 Butter knife

Ø  Take a cup of about 3 inches height.

Ø  Prepare plaster of paris in the cup.

Ø  Use the butter knife to cut a narrow one inch deep groove into the plaster of paris before it dries.

Ø  The grooves should not touch the edges of the container.

Ø  Allow it to dry completely.

Ø  Carefully tear the container away to reveal your block. Measure the size of the groove. Fill the groove with water and place the block in the freezer.

Ø  After the water has frozen, remove the block and record your observation. Allow the ice to melt and place it in the freezer again. Repeat this till the block brakes.

Make a sand stone :

Things needed :

v  Fine sand

v  Two paper cups

v  Water

v  Epsom salt

How to make ?

   v  Take a paper cup. Drop 1 inch of fine salt into it.

   v  Fill another cup with water  about 1 inch high.

   v  Add Epsom salt slowly with stirring still no more salt dissolves.

   v  Pour the Epsom salt solution over the sand in the cup. Stir well.

   v  Place the mixture in a place where it will dry.

   v  It will take few days to dry.

   v  When it is completely dry, take the paper cup away from the sand.

Sun loving algae

You will need :

A jar with a lid and some pond water, aluminum foil.

• ·         Fill the jar with the pond water , and cover it with a lid.
• ·          Wrap the jar up completely with aluminum foil. Make sure that there are no uncovered places.
• ·         Now cut a small hole, about 1 centimeter wide, in the foil.
• ·         Place the jar on a window sill. Turn the hole towards the light. Leave it there for few hours.
• ·         Carefully remove the foil without disturbing the water.
• ·         You will find that the algae has clustered around the spot where the light entered through the hole.

HEARTBEAT

PURPOSE : To observe the vibration of a match due to the pulsation of blood in the wrist.

MATERIALS : Modeling clay
                            Paper match

PROCEDURE :

• Insert the match onto a very small piece of clay ( the smaller the better )
• Flatten the bottom of the clay.
• Place your wrist, palm side up, on the table.
• Place the clay on your wrist, and move the clay around on the thumb side of the wrist until the match starts to slowly vibrate back and forth.
• Count the number of vibration that the match makes in one minute.

RESULTS :  The match vibrates back and forth with a regular beat. For adult it will vibrate 60 to 80 times in one minute. The vibration for childern is from 80 to 140 beats per minute.

WHY ? As the heart contracts, blood is forced through the blood vessels. The blood moves at a rhythmic rate causing the blood vessels in the wrist to pulsate. All blood vessels have this throbbing motion, but the vessels in the wrist are close to the surface of the skin and can be felt more easily. The movement of the blood under the clay causes it and the match to vibrate.

LUNG CAPACITY

PURPOSE : To measure the amount of air that can be forced out of the lungs.

MATERIALS : Plastic dishpan
                           2 feet ( 61 cm ) of aquarium tubing
                           1 gallon ( 4 liters ) plastic milk jug with cap
                           Masking tape
                           Pen

PROCEDURE :

• Place the strip of masking tape down the side of the milk jug from top to bottom.
• Fill the jug with water, and screw on the cap.
• Fill the dishpan about 1/2 full with water.
• Place the jug upside down in the water, and remove the cap.
• Have a helper hold the jug. Do not allow air bubbles to enter the milk jug.
• Place one end of the aquarium tubing inside the mouth of the jug.
• Take a normal breath and exhale through the tubing. Mark the water level on the tape.
• Refill the jug with water and return it to the dishpan.
• Breath in deeply and make an effort to exhale all of the air out of your lungs through the tubing. Mark the water level on the tape.

RESULTS : The water level drops as exhaled air enters the jug. Normal breathing does not push out as much water as does deep breathing.

WHY ?When the air enters the jug it pushes the water out the opening. In normal breathing, only about one eighth of lungs' capacity is used. During exercise, more air is taken in and exhaled, thus there is a amount of air exhaled during deep breathing.

FUZZ BALLS

PURPOSE : To determine the best way to grow penicillin.

MATERIALS : Cotton balls
                           2 oranges
                           2 lemons
                           2 bread sacks
                           Bowl

PROCEDURE :

• Rub the fruit on the floor.
• Place the fruit in a bowl exposed to the air for one day.
• Place in each bread sack an orange, a lemon, and a cotton ball wet with water.
• Secure the ends of the sacks.
• Place one sack in the refrigerator and the other in a warm dark place.
• Leave the sacks closed for two weeks.
• Observe the fruit through the sacks daily.

RESULTS : The fruit in the refrigerator looks the same or possibly a bit dryer, but the other fruit has turned into blue green fuzzy balls.

WHY ? The green powder growth on the outside of the fruit is penicillius. Under a microscope this mold looks like a small brush thus it was named from the latin word penicillus meaning a paint brush. Because brushes were used to write with at one time, our modern writing tool, the pencil, is named after the latin word for paintbrush. Molds can grow in hot places, but they grow faster and in more abundance in moist warm places. This is why foods become more moidy in the summertime. Placing bread in a bread box or on top of a refrigerator causes them to mold more quickly. Cooling foods slows down the growth of mold and freezing keeps foods fresh for much longer periods of time. 

WATER DROP LENS

PURPOSE : A water drop is used to simulate an eye lens.

MATERIALS : One 6 inch (15 cm) piece of 20 gauge wire
                           Pencil
                           Bowl
                           Newspaper

PROCEDURE :

• Twist one end of the wire around the pencil to make a round loop.
• Fill the bowl with water.
• Dip the wire into the water with the open loop pointing up.
• Lift the loop carefully out of the water and hold it over the newspaper. You want a large rounded drop of water to stay in the hole of the wire loop.
• Look through the water drop at the letters on the page. You may have to move the loop up and down to find a position that makes the letter clear.

RESULTS : The letters are enlarger. If the letters look smaller dip the loop into the water again.

WHY ? The water drop is curved outward and acts like a convex lens. This type of lens is used as a magnifying lens and is the type of lens is eyes. Sometimes the water drop stretches so tightly between the wire that it curves downward forming a concave lens. This type of lens causes the letters to look small. 

HAVE AN ONION

PURPOSE : To determine your sensitivity to taste.

MATERIALS : Toothpicks
                            Blindfold
                            Spring type clothespin
                            Apple
                            Onion

MATERIALS :

• Cut the apple and onion into small bite size pieces of equal size.
• Ask a helper to assist you with the experiment. Without seeing or smelling, the person will decide on the identity of the food by taste only.
• Blindfold the helper and place the clothespin on his or her nose. An old clothespin with a weak spring is best so that it will not pinch too tightly.
• Use a toothpick to place a piece of apple in the helper's mouth and give instruction to chew it and identify what the food is. It is important that the helper has not seen the food samples before the experiment starts.
• After making an identification, have your helper remove the nose clip and compare the taste when odor is included.
• Replace the clip and blindfold then use a toothpick to place the onion poece in your helper's mouth.
• Ask for an identification.
• Remove the clip and again ask for an identification.

RESULTS : Without smelling the apple and onion have a similar taste. The texture of the food will give clues, but the taste is the same.

WHY? The tongue has nerve ending that allow one to taste things that are sweet, sour, salty, or bitter. Most of the taste sensations experienced are due to smell. Make a note of how tasteless food seems the next time you have a cold and cannot breath properly.

NAKED EGG

PURPOSE : To demonstrate the semi-permeability of a cell membrane.

MATERIALS : 1 raw egg in its shell
                           1 Jar with a lid ( the egg must fit inside the jar )
                           Clear vinegar
                           Flexible measuring tape

PROCEDURE :

• Measure and record the circumference around the center of the egg.
• Record the apperance of the egg.
• Place the egg inside the jar. Do not crack the shell.
• Cover the egg with vinegar.
• Close the lid.
• Observe immediately and then periodically for the next 72 hours.
• Remove the egg after 72 hours and measure its circumference.
• Compare the appearence of the egg before and after being in the vinegar.
• How has the egg changed in appearence and size?

RESULTS : The egg has a hard shell on the outside and the circumference will vary. Bubbles start forming on the surface of the egg's shell immediately and increase in number with time. After 72 hours the shell will be gone and portions of it may be seen floating on the surface of the vinegar. The egg remains intact because of the thin see-through membrane. The size of the egg has increased.

WHY ? The shell of the egg is made of calcium carbonate, commonly called limestone. When vinegar reacts with the limestone, one of the products is carbon dioxide gsa, those bubbles seen on the egg.The membrane around the egg does not dissolve in vinegar, but becomes more rubbery. The increased size is due to osmosis, the movement of water through a cell membrane. The water in the vinegar moves through the thin membrane onto the egg because the water inside the egg has more materials dissolved in it than does the vinegar. Water will always move through a membrane in the direction where there are more dissolved materials. The contents of the egg stayed inside the membrane because these molecules were too large to pass through the tiny holes. This selectiveness of materials moving through the membrane is called semi-permeability.  

BACTERIAL GROWTH

PURPOSE : To demonstrate the effect that temperature has on the growth of bacteria.

MATERIALS : Milk

                        Measuring cup (250ml)

                        2 (500 ml) jars

                        Refrigerator

PROCEDURE : 

• Put a cup of milk in each jar
• Close each jar.
• Place one jar in the refrigerator.
• Place the second jar in a warm place.
• Examine the milk in each jar once for 7 days.

RESULTS : The warm milk has thick, white lumps in it and smell sour. The cold milk looks and smells like drinkable milk.

WHY ? Warm temperature promote the growth of bacteria that can cause food to spoil. Cooler temperature slow down the bacteria growth, but milk will eventually spoil if left in the refrigerator long enough. The bacteria are present and grow very slowly when cold, but they do grow.

LIGHTS OUT

PURPOSE : To determine the effect of sunlight on plant survival.

MATERIALS : House plant 

                          Black construction paper

                          Scissors

                          Tape (cellophane)

 PROCEDURE :

• Cut two piece of black construction paper large enough to civer one leaf on the plant.
• Sandwich the leaf between the two paper pieces.
• Tape the paper together. It is important that the leaf not receive any sunlight.
• Wait 7 days.
• Uncover the leaf and observe its color.

RESULTS : The leaf is much paler than the other leaves on the plant.

WHY ? A green chemical called chlorophyll gives leaves their green color. In the absence of sunlight the green pigment is used up and not replenished in the leaf resulting in a light colored leaf. Since chlorophyll is necessary for plant survival the leaf will die without sunlight.

WHAT'S STOMATA?

PURPOSE : To determine which side of the plant leaf takes in gases.

MATERIALS : Potted plant

                          Vaseline

PROCEDURE :

• Coat the top of four leaves with a heavy layer of vaseline.
• Coat the under side of four leaves with a heavy layer of vaseline.
• Observe the leaves daily for one week.
• Is there any difference in the two sets of leaves ?

RESULTS : The leaves that had vaseline coated on the underside died. The other leaves remained unchanged.

WHY ? Openings on the under side of the plant leaves called stomata allow gases to move into and out of the leaves. The vaseline plugged the openings and the leaf was not able to receive necessary carbon dioxide gas or eliminate excess oxygen gas. 

FOOD PRODUCERS

PURPOSE : To demonstrate that starch, a food substance, is produced in leaves.

MATERIALS : Paper towels

                          Tincture of iodine

                          Leaf ( pale green )

                          Rubbing alcohol

                          Shallow dish

                          ( 500 ml ) jar with lid

                           Measuring cup ( 250 ml )

PROCEDURE : 

• Place the pale green leaf in the jar. The paler the leaf , the easier it will be to extract the green pigment, chlorophyll.
• Pour one cup of alcohol into the jar. Put the lid on the jar.
• Allow the jar to stand for one day.
• Remove the leaf and dry it by blotting with a paper towel.
• Lay the leaf in the shallow dish.
• Add enough iodine to cover the leaf.

RESULTS : Dark areas appear on the leaf.

WHY ? Photosynthesis is an energy producing reaction that occurs in the leaves of plants. Starch, a food substance is one of the product of this reaction. Soaking the leaf in alcohol removes the wax coating on the leaf plus it partially removes the green pigment chlorophyll. It is easier to see the result of the starch test without the presence of the green chlorophyll. Iodine combines with starch particles to form a dark purple to black color.