Alpha science classroom： A Candle Seesaw Balancing Act

Kids love seesaws in the park, why do you sit on the beam and the weight on the other side makes you either fly into the air or fall to the ground? The answer to all of this lies in the A Candle Seesaw Balancing Act prepared in the Alpha Science classroom. This physical science experiments activity for children explains the mystery of balance force through simple physical phenomena. Let children learn knowledge and enjoy the magic of science in the process of kid's science experiments.

Alpha Science Classroom： A Candle Seesaw Balancing Act, materials

• Two identical birthday candles

• Strong adhesive tape

• Needle longer than the diameter of the candle

• Aluminum foil

• Knife

• Two cups of the same height

• Lighter or matches

• Adult helper

Alpha Science Classroom： A Candle Seesaw Balancing Act, experimental steps

Step 1:The children glued the ends of the birthday candles together so that the two wicks were facing in opposite directions. Then place a large piece of aluminum foil in your work area to protect it from any wax spills.

Step 2: Children place two glasses right next to each other in the middle of the foil. The gap between the glasses should be small enough to get the needle through them.

Step 3: Children carefully take the needle and push it all the way to the side of the candle where the ends of the two candles meet exactly. This should be right in the middle between the two wicks. If it is too difficult to push the needle through the candle, try heating the needle in the flame and then pushing it through the wax.

Step 4: The children place the candles in the gaps between the glasses so that the needle sticking out on either side of the candle rests against the edge of each glass. Make sure your surface is covered with aluminum foil along the entire length of the candle.

Step 5: Children should remember to ask their adult helper to carefully light both candles once the candles are balanced and neither side has fallen out. Do not light both candles at the same time, wait a few seconds and then light the second one.

Step 6: The children observe the two candles burning and observe the movement of the candle seesaw.

Place the candles between the glasses again so that the pinheads sticking out on either side of the candle are partially against the edge of each glass.

Step 7: Once again, children, ask your adult helper to light the two candles in the same manner as before. Watch the candles burn and observe what happens.

Alpha Science Classroom: A Candle Seesaw Balancing Act, Scientific Principles

Have kids ever noticed that what you are building looks like a seesaw? Two candles are taped together to form a long beam that is attached to a pin that acts as a pivot (or fulcrum). The candles are free to rotate from one side to the other like a real seesaw. Since you are not putting any additional weight on the candle beam as you would on a playground seesaw, the only force pulling down on the beam is the weight of the candle itself. In order to balance the seesaw, it is important that the two forces pulling down on each side of the beam are exactly the same. This is only true if the needle is exactly in the middle of the candle. If one side is slightly longer, this will also make it heavier and will fall as you observed. However, if the needle is placed in the middle

This will change once you light the candle. When the candle burns, a chemical reaction occurs that converts the candle wax into a gas. You may also notice that the solid wax turns into a liquid and drips onto the aluminum foil. The wax lost through combustion and dripping makes the candle shorter and therefore lighter. As this side of the candle gets lighter, it moves up and the heavier side of the other side drops down. Once the other candle loses wax and becomes lighter again, the rotation reverses. The key to this seesaw motion is that both candles do not lose the same amount of wax at the same time. This is why you have to light them one after the other. If both candles start burning at the same time and lose the same amount of wax at the same time, then the candle seesaw will remain balanced.

If you cut a part of the candle on one side, the longer, now heavier side of the beam will fall. When you light the candle, you may notice that the candle seesaw does not move at all, because when both candles are burning, the longer side is always heavier. However, if you light only the heavier side of the candle, you will notice that once the candle burns enough to make it shorter and lighter, the seesaw will fall off the other side.

A machine like a seesaw is designed to lift objects that are much heavier than you can lift on your own. A seesaw is a special type of lever that consists of a long beam that is attached to a pivot point called a fulcrum. Once you sit on the side of the beam to place your weight on one end, it falls to the ground. This is because gravity acts on the mass of your body, pulling the beam down. The weight that pulls down the beam depends on your weight. The heavier you are, the greater the gravitational force. To balance the beam again, you need to apply a reaction force on the other side. One possibility is to place another person of the same weight on the other side of the beam.

However, you probably know from experience that it is not only the weight that matters but also the position of people sitting on the beam. Two people of the same weight sitting on either side of the beam can still change their balance and make the seesaw rotate by moving away from or closer to the center of the beam. The rotation of the beam is caused by the rotational force, also called torque, which takes into account the force pulled on the beam and the position of the applied force.

Once the rotational forces on both sides are equal and cancel each other out, the seesaw stops rotating, as stated by the law of leverage. This law also explains why you can use a lever to lift very heavy objects. When the object on one side is too heavy for you to lift, you simply move away from the center of the beam until your rotational force is greater than the rotational force on the other side.

The mystery of the seesaw was answered in this children's physical science experiments, and I believe that the children have mastered the mystery, which is what alpha science classroom wants most, to open the door of exploring science for children with various amazing scientific phenomena, and to help children learn through interesting kid's science experiments activities, which is the greatest charm of science experiment. We hope that children will learn and grow happily through such activities and become the greatest scientists. alpha science toys for children designed the same interesting children's physical science experiment kits, a variety of magical force movement principles, magical visual, for children to open the door to explore the physical science, to help children learn, become the happiest science wizard.