What happens when you burn a candle at both ends?

What happens when you burn a candle at both ends?

Materials needed

• Candle
• Match
• Toothpicks
• Water glasses

Procedure

1. Prepare a candle so the wick may be lighted at both ends.

2. Insert round toothpicks into the candle and balance it on the water glasses as shown in the illustration. It doesn't have to balance perfectly.

3. Predict what will happen if you light body ends of the candle.

4. Light both ends of the candle. Observe for several minutes. What happened?

5. Think about it. And explain what happened the best you can. Share your ideas with others in your group.

Teacher information

Caution: activities with fire or heat should be done only under close adult supervision or as a teacher demonstration.

                When the candle is lighted at both ends, the end tilting downward will burn wax away more rapidly and become lighter. When it tilts up, the other end will be down, and it will burn wax away more rapidly. As this process continues to reserve, the candle will rock back and forth, often quite vigorously.

How does gravity affect heavy and light objects?

How does gravity affect heavy and light objects?

Materials needed

• Large book
• Small book
• Wadded paper
• Pencil
• Eraser
• Paper clip
• Paper

Procedure

1. Take the large book in one hand and the small boo in other. Hold the two books at exactly the same height.
2. Drop both books at the same time, but before you drop them, predict which one will fall faster. Have someone watch to see which book hits the floor first.
3. Repeat the book drop three times to be sure of your results.
4. Which book falls faster, the large one or the small one?
5. Compare the pencil and the paper in the same way. First predict which you think will fall faster.
6. Compare the various objects, two at a time. In each case predict which will fall faster, and then drop them together three times to test your prediction.
8. Explain how the force of gravity compares with objects that are large, small, heavy, and light, according to your findinding, how do the falling speeds compare?
9. Compare the falling speed of the wadded paper with that of a flat sheet of paper dropped horizontally.
10. Compare the falling speeds of two flat sheets of paper, one dropped vertically and the other horizantly.
11. Compare the falling speed of the wad of paper with that of a flat sheet of paper dropped vertically.
12. Discuss your observations with your group.

For problem solvers: 

go to encyclopedias and other resources and do some research about gravity, can you find out what really causes gravity? How large does an object have to be in order for it to have a gravitational attraction for other things? How much do scientists know about gravity?

Teacher Information

The force of gravity pulls all objects to the earth at the same rate, regardless of the size or weight of the object. Air resistance can slow the rate of fall, so the flute paper held in horizontal position will fall more slowly. Except for the factor of air resistance, however, the rate of fall is equal. A rock and a feather will fall at the same speed if placed in a vacuumed chamber.
Scientists are still trying to figure out exactly what gravity is. They have learned a great though the force is too weak to really notice unless the objects are huge, as with planets and stars.

How can the energy of sound cause something to move?

How can the energy of sound cause something to move?

Materials needed

• · Two guitars

Procedure

1. Be sure the two guitars are tuned alike.
2. Stand the two guitars face to face, about 5-10 cm (2-4 in.) part.
3. Strum the strings of one guitar. After two or three seconds, silence the strings of the guitar you strummed by putting your hand on them.
4. Listen carefully to the other guitar.
5. What do you hear? How did it happen?

Teacher information

This activity shows that sound can actually do work. It can make something move. Energy is transferred from one guitar to other by sound waves. And the strings of the second guitar vibrate. The two guitars should be tuned alike so the vibrating frequency is the same for the two sets of strings.

How to make Cotton candy

Concept 
When sugar is heated, it becomes a liquid caramel. If you continue to heat, the sugar burns out. When caramel is pushed out from tiny holes to the outside by using the centrifugal force, the cotton candy
can be made.   The cotton candy making machine can be made with easy available materials.

Materials 
tea strainer of metal, motor, wire, spirit lamp, pin, adhesive tape, rubber t ube, aluminum plate, dry battery, conducting wire, cardboard box, and crystallized sugar

Fabrication 

1. Cut the aluminum plate as like the gear wheel for the tea strainer lid, and the hole for putting sugar is made, too.
2. Bend two places on the tea strainer grip.
3. The pin and the rubber tube are pu t up to the axis of the motor. 
4. The connection of the motor and the tea strainer is made from the wire.
5. The spirit lamp is put in the cardboard box and ignited.
6. The crystallized sugar is  put in the tea strainer. 
7.  The motor is connected to the dry battery after heating s ugar with the spirit lamp for a while. 

Cotton candy making

part of rotor

the joint of motor

Cotton candy making diagram

good Cotton candy making