# Balloon Controlled Roller Experiment

### Aim:

To make a roller rotate with the help of a balloon.

### Materials Required:

1.      An empty cylindrical soda can.

2.      An inflated balloon.

### Procedure:

1.      Place the can on a smooth horizontal table or floor and hold the can such that the can stays still.

2.      Rub the balloon on your hair or take any woolen cloth and rub the balloon on it vigorously.

3.      Next take the balloon and hold it about an inch away from the can. We will see the can will slowly start to roll.

4.      Then make the balloon move by maintaining the distance and we will see that the can also starts to move along with the balloon.

5.      If we bring the can to the other side we will see that the can will follow the balloon.

### Scientific Explanation:

This is possible because of static charge. When we rub the balloon on our head the balloon gets charged with static electricity and polarizes opposite charge on the can. This develops a force of attraction as opposite charges attract and the can begins to follow the balloon as we move the balloon. We should try the same experiment to see if the can rolls uphill or not. We should also check how far the can rolls.

Principle of Xerox Machine: Even Xerox machine uses static electricity to make copies. In a Xerox machine there is a drum made of plastic. When we put a piece of paper that needs to be Xeroxed, a copy goes to the drum. There drum has static charge. This attracts the powdered black plastic powdered toner according to the dark areas of the paper. The toner melts and makes black letters on this new piece of paper. This is just like electrons (negatively charged) attract protons (positively charged).

# Egg in a Bottle Science Fair Project

### Aim:

The aim of this science project is to insert an egg into a glass bottle whose neck diameter is smaller than the egg, and thereby learn the effect of atmospheric pressure.

### Materials Required:

1. Hard boiled egg
2. Matchsticks
3. Long narrow necked bottle

### Procedure:

1. Select a bottle with a narrow and long neck and set it on a level surface. Select a bottle such that it’s opening is just enough to prevent the egg from falling inside.
2. Light three matches and put them into the bottle
3. Swiftly put the egg on the mouth of the bottle.

### How does this happen?

As the matches reach the inside of the bottle, the air inside the bottle heats up. As air get heated up it expands. As the volume of air increases it escapes through the mouth of the bottle. As the matches go out the air inside the bottle cools and takes up lesser volume (contracts) thus an area of low pressure is created compared to the outside pressure. The higher pressure outside the bottle forces the egg into the bottle.

How do you get the egg outside the bottle?

Blow air inside the bottle and turn the bottle upside down. The increased pressure in the bottle will force the egg out of the bottle.

# Glue Stick Sun Set Demonstration

The blue sky and the red sunsets are due to the scattering of light by the atmosphere. This can be modelled when light from a flashlight shines through clear glue sticks.

### Aim:

The aim of this science fair project is to model the blue sky and red sunset using simple materials.

### Materials Required for the Project:

1.      A pencil torch

2.      4 to 6 glue sticks (must be the clear ones used in glue guns)

3.      White background (paper, wall or cloth)

4.      Clear packaging tape

5.      Two polarizing filters

### Procedure:

1.      Switch on the pencil torch and shine it into one end of a glue stick. Hold the other end of the glue stick approximately 1cm from the white background. There will difference in colour between the end of the glue stick which is closer to the pencil torch and the end of the glue stick which is nearer to the white back ground. The colour of the circle on the white background should be noticed.

2.      Place two glue sticks end to end and attach them together with the clear tape.

3.      Repeat the experiment with the pencil torch and notice any difference in the colours along with the glue sticks and in the coloured circle on the white background.

4.      Notice the changes in colour and intensity along the glue sticks and in the coloured circle by attaching more glue sticks with the clear tapes.

### How does this happen?

The white light will be emitted from the pencil torch. Out of the pencil torch beam, the blue light will be scattered by the glue stick more than that of the yellow and red light. The end of the glue stick which is nearer to the pencil torch appears blue since the first colour to be scattered is blue. The other end is yellow to yellow-orange. When the glue sticks are joined the length will increase and more yellow light will be scattered. Then the coloured circles changes to an orange colour.

I think this experiment, glue stick scattering model provides you a demonstration of why the sky is blue and sun sets are red. Since the blue light is most readily scattered from sunlight in atmosphere, the sky looks blue. This is just as same as the blue light was most readily scattered from white light in the glue sticks. If blue light was not scattered in the atmosphere, the sun would look a little less yellow and a little more whiter and the rest of the sky would be black.

# Simple Electric Motor – A Science Fair Experiment

### Aim:

To make a simple electric motor to amaze your friends.

### Materials Required:

1. A copper wire
2. An AA battery
3. Small magnetic discs

### Procedure:

1. Remove the insulations of the copper wire
2. Shape the copper wire as shown as in the video
3. Make the magnetic discs into a cylinder and stand the battery on them so that the negative pole touches the magnets.
4. Place the copper wire as shown in the video.

# Simple Science Project to Demonstrate the Effect of Inertia

What is inertia? According to Newton’s second law of motion inertia is the ability of a body to maintain its state of rest or of uniform motion without the application of an external force.

The following physics project is a simple experiment to demonstrate inertia.

Aim:

To demonstrate inertia.

Materials Required:
1. Index card
2. nickel
3. drinking glass
Procedure:
1. Lay down the index card so as to cover the mouth of the glass.
2. Place the coin on top of the card such that its position is to be centered over the mouth of the glass.
3. Now snap the card with your finger.

Result:

When you snap the card it quickly moves forward making the coin to drop into the glass.
The explanation behind this is that because of Gravity the coin falls into the glass. Both the card and the coin are stationary and are said to be at rest. They remain inert because of their inertia. So when you snap the card, it slips under the stationary coin as the coin tends to maintain its state of rest ie, inertia.

# Fireproof Balloons Experiment

Fire proof Balloons

To raise the temperature of iron is easier than to raise the temperature of water! It takes just 1/10th time to raise the temperature of 1 gram of iron than it does to raise the temperature of 1 gram of water. Water has a unique property of being able to absorb a lot of heat compared to other materials. Water cools quickly too. This is the reason why places near to water bodies have a temperature that is neither too cold nor too hot.

To realize the heat absorbing potential of water we shall do an experiment.

Materials required:

2. Small funnel
3. Water
4. Matchsticks
5. Two big balloons

### Procedure:

1. Fill air into the first balloon and tie a knot at its end with the thread. Light the matchstick and bring it closer to the balloon. As the matchstick is brought closer to the balloon the balloon begins to melt and burst.
2. Take the second balloon and insert the funnel into its mouth fill about 70 ml of water. Blow air into the balloon and tie the end with the thread.
3. Light the matchstick and place it below the balloon just like what we did with the first balloon.

### Result:

The second balloon does not burst as easily as the first one because the heat provided by the match stick was absorbed by water. As the water starts absorbing more heat it reaches a point where it can no longer absorb heat. At that point the balloon bursts.

# Create ‘After Images’ Experiment

This Science Fair Project is about ‘after images and how they are produced. When you look at the sun in noon for few seconds and after that if you look into the surroundings, you can see dark images in front of your eyes which are called ‘after images’.

Materials Required for the project:

1. A sheet of White paper
2. A flashlight
3. An Opaque tape

Procedure of the Project:

1. The white paper we have is taped over the lens of the flashlight and most of this paper is covered with strips of the opaque black tape. In order to shine the light through the paper, leave an area uncovered, which can be of any shape but should be at the centre of the lens.

2. Switch on the flash light in a dark room, hold it at arm’s length and shine it into your eyes.

3. Focus at any particular point of brightly lit shape for about 30 seconds.

4. Focus at a blank white wall and blink your eyes for few times. You can see an image which is called ‘after image’.

5. The shape and colour of the image seen on the wall should be noted.

6. Now close your left eye and focus to the bright image with the other eye for few seconds. Then close your right eye and look at the white wall with your left eye. Now you will not see an ‘after image’.

Scientific Explanation of the effect:

We see with the help of Retina which is the light sensitive lining at the back of our eye. A part of the retina is de-sensitized through prolonged stimulation by a bright image. Here it is the light source. The light reflecting from the wall shines when we look into the white wall. The part of the retina desensitized by the bright image will not respond to the new light input as its other sensitive parts do. This desensitized area appears as a negative ‘‘after image’ ’, a dark area that matches the original shape. The ‘after image’ may last for 30 seconds or longer.

The apparent size of the ‘after image’ depends on size of the image on your retina as well as on how far you perceive the image to be. If you use your hand instead of the white wall, you see your negative ‘after image’ on your hand. This is because, your hand is closer to you and so you see the image as relatively small, not larger than your hand. When you look at the distant wall instead of hand, you can see the negative ‘after image’ on it but the size is different from that of the hand. The size is bigger and the negative ‘after images’ covers a reasonable part of the white wall. This means that the negative ‘after image’ is not actually on either surface, it is on the retina. So the actual size of the ‘after image’ does not change but your interpretation of its size changes.

# Homemade Gyroscope Experiment with Bicycle Wheel

### Aim:

To demonstrate the principle of conservation of angular momentum using a homemade gyroscope mechanism.

### Materials required:

1. A rotating chair or stool.
2. A bicycle wheel.
3. Two handles which can be attached using a bolt to the axle of the wheel.

### Procedure:

1. Screw the handles to the centre of the bicycle wheel on both sides.
2. Sit on the rotating chair or stool with your feet off the ground and hold the wheel by its handles with a tilt in one direction.
3. Ask someone to rotate the wheel you are holding. You will see that your chair will spin in one direction.
4. Now tilt the wheel in the opposite direction and ask your friend to rotate it again. You will see that the chair spins in the opposite direction now.

### Scientific explanation:

This phenomenon occurs due to angular momentum. Any rotating body has angular momentum. Hence the bicycle wheel has angular momentum when it is set to spin. The wheel and the chair together make a system. This system obeys the principle of conservation of angular momentum. Hence when the wheel spins in one direction at one orientation, the wheel will exert an equal and opposite force on you and the chair, thereby rotating it in the opposite direction.

# Magnetic Shielding Experiment

### Aim:

To show that magnetic materials are permeable while others are non-permeable.

### Materials Required:

1.      A magnetic rectangular bar.

2.      Two cardboard (5cms*7cms).

3.      Two pencils

4.      Five or six clips.

5.      Straw or ice cream stick or any nonmagnetic material.

6.      Any strip of metal (or even a metallic knife).

7.      Glue or duct tape.

### Procedure:

1.      Paste the pencils to both the cardboards. Place the pencils on the edges as it gives us more room for the experiment.

2.      Take the second piece of the cardboard such that it forms a cardboard-pencil- cardboard sandwich.

3.      Now paste the magnet on top of the cardboard pencil sandwich. Place it on the centre of the edge of the cardboard.

4.      The clips are raised up to the bottom of the shielding sandwich one at a time. Notice what happens.

5.      The clips are attracted to the magnet and hangs at the bottom of the cardboard sandwich. If it does not happen then either the cardboard taken is too thick or the magnet is too weak to attract. In either case we can solve this problem by adding another magnet to the first.

6.      Now we take the Popsicle stick or the straw and insert it between the two cardboards. We notice that the clips made of iron are still attached to the bottom of the sandwich. They are unaffected.

7.      We now take the metallic knife (preferably made of iron) and insert it in the sandwich. We notice that the clips fall off.

8.      Now take other materials like coins and insert it in the sandwich and note whatever happens to the clips.

### Scientific Explanation:

It is because different materials show different level of permeability to the magnetic lines of forces. Materials like Popsicle stick or straw or even wood which cannot be magnetized are known as non-permeable. The magnetic lines of forces pass through such materials. Other materials which are generally metals are known as permeable. They actually gather the lines of forces and do not let the lines pass completely through it.

# Crazy pendulum Experiment

### Aim:

To understand the chaotic motion of a pendulum under the influence of magnetism.

### Materials required:

1. 7 ring magnets.
2. A ring stand.
3. Some chalk.
4. String.

### Procedure:

1. Arrange the magnets in pairs so that they stick together magnetically.
2. Arrange these pairs at the corners of an equilateral triangle on the base of the ring stand.
3. Hang a magnet from the ring stand so that it is free to swing as a pendulum. Make the string just long enough so that the magnet will swing close to the magnets kept on the base but won’t touch them.
4. Give the hanging magnet a slight push to set it in motion. Watch the strange and unpredictable patterns of movement.

### Scientific explanation:

Although a simple pendulum’s motion is easy to predict, when you add magnets the forces of magnetism and gravity act on the swinging pendulum in very complicated ways which results in chaotic motion. The motion of the pendulum seems completely unpredictable but there is a complex pattern to it which can only be found over a long period of time. Physicists use models called strange attractors to describe this motion.