experiments on air volume and temperature
When a gas such as air is compressed, its temperature rises, and when it expands, its temperature drops. This is an experiment using this property.
Experiment 1: Let's ignite with a compression igniter
you need : Compression ignition device, thin paper
Prepare the ignition device. Place a small amount of paper on the ignition table. Raise the compression rod and push it. Ignite.
Easily calculate the temperature change at this time. Assuming the volume is compressed to 1/10 , the temperature is 27 ° C ( 300 K).
There is a relationship of T1 = T0 (V0 / V1) ^ 0.4, and if you put a numerical value in this,
T1 = 300 (1 / ( 1/10 )) ^ 0.4 = 300 * 10 ^ 0.4 = 300 * 2.51 = 753K = 753-273 = 480 ℃
The ignition temperature of paper is about 450 ℃, so it burns. It was used as a portable igniter in Southeast Asia. Did you know that the diesel engine was developed based on this compression igniter? Details can be found at the Kansai University Museum. Please follow the link below
Experiment 2: Let's make clouds with PET bottles
you need : PET bottles, incense sticks, lukewarm water
Prepare a plastic bottle. Add lukewarm water and fill with steam. Add incense smoke to make it easier for water vapor to condense. Cover and compress by hand. When you release your hand, it expands and the temperature drops, and the water vapor turns into water and becomes a cloud.
Experiment 3: Let's make a PET bottle thermometer
you need : PET bottles (carbonated drinks), two straws tightly connected, food coloring, adhesive, awl
Make sure your PET bottles are solid for sodas. Connect two straws and pass them through the lid. Dye with food coloring to make the liquid easier to see. Add about 100 ml of air and close the lid tightly. When the temperature changes by 1 ° C, the volume changes by 1/273. With a straw with a diameter of 5 mm, the water level changes by 0.37 cm, so the water level changes by about 0.46 cm. Make sure that air and liquid do not leak.