How to Make a Candle Seesaw

The seesaw candle is a simple and easy science experiment for kids at school or at home. That teaches how Newton's Third Law of Motion works. The candle acts like a seesaw. It is super fun.

Age: 5+         Time: <20min

 Safety 

1. Be careful with the fire. Make sure there is no flammable around.

2. Be careful with the knife and a paper clip.

3. Adult supervision.

 Materials List 

• Candle
• Lighter
• Paper clip or needle
• Beakers or cups
• Pliers
• Knife

 Instruction

Step 1/6 –Sharpen the bottom of the candle to expose its wick.

Step 2/6 – Find a balance point and make a mark. It is usually at the center.

Step 3/6 – Straighten the paper clip. If you have the needle, you do not have to this step.

Step 4/6 – Heat the straightened paper clip and force it through the balance point.

Step 5/6 – Balance the candle between two beakers. It is okay if one end of the candle is heavier than the other.

Step 6/6 – Light low end of the candle and then the up end, and see what happens.

 Troubleshooting 

Why my seesaw swing slightly?

— make sure the candle is not too short and there is not too much friction prevent it swing. You also can give the seesaw help by making it swing. Once it begins to swing, it will keep swinging.

 Question to Ask 

1. Can candle be replaced by other stuff, like a wooden stick?

 Scientific Description 

The candle moves in response to the weight of both ends of the candle. The low end of the candle is heavier than the up end of the candle. When one end of the candle goes down, it is angled such that the flame melts the wax, causing it to drip down. With the dripping of the wax, the low end of the candle is getting lighter, and eventually, the low end is lighter than the up end of the candle so it goes up. And, the up end of the candle goes down. Aside from the lessen mass, the dripping wax actually pushes the end of the candle up, according to Newton's Third Law of Motion. The whole process of up and down reverses. 

 Extensions 

Can you make the candle to rotate a whole around?