When the plunger of the syringe was pulled out the pressure decreases so th volume increases, this can be related to the appearance of the marshmallow wherein it gets smaller when plunger was pushed in that increases the pressure and its becomes big in the absence of pressure or when the plunger was pulled out Bring Science Home A pressure-filled science project from Science Buddies
Key Concepts Physics Gas Pressure Volume Boyle's Law Introduction Background You can observe a real-life application of Boyle's Law when you fill your bike tires with air. When you pump air into a tire, the gas molecules inside the tire get compressed and packed closer together. This increases the pressure of the gas, and it starts to push against the walls of the tire. You can feel how the tire becomes pressurized and tighter. Another example is a soda bottle. To get carbon dioxide gas into the liquid, the whole bottle is usually pressurized with gas. As long as the bottle is closed, it is very hard to squeeze, as the gas is confined to a small space and pushes against the bottle's walls. When you remove the cap, however, the available volume increases and some of the gas escapes. At the same time its pressure decreases. One important demonstration of Boyle's law is our own breathing. Inhaling and exhaling basically means increasing and decreasing the volume of our chest cavity. This creates low pressure and high pressure in our lungs, resulting in air getting sucked into our lungs and leaving our lungs. In this activity you will create your own demonstration of Boyle's law. Materials
Observations and Results The results look different with the water-filled balloon. Although you are compressing the air inside the syringe when pressing on the plunger, the water inside the balloon does not get compressed. The balloon stays the same size. The water balloon also keeps its shape when pulling out the plunger while closing the tip of the syringe. In contrast to gases, liquids are not compressible as their particles are already very close together. Boyle's law only applies to gases. If you filled the syringe with water as well, you should still have seen the air-filled balloon shrinking while pushing the plunger into the syringe. The air-filled balloon also should have expanded when pulling the plunger out while the tip of the syringe was closed. You might have noticed, though, that you were not able to push and pull the plunger in and out as far as you could with the air-filled syringe. This is again because of the fact that liquids cannot be compressed like gases. You should have observed that also when trying to push the plunger in or pull it back in the water-filled syringe with the water-filled balloon. It was probably impossible to move the plunger in and out! More to Explore This activity brought to you in partnership with Science Buddies Discover world-changing science. Explore our digital archive back to 1845, including articles by more than 150 Nobel Prize winners. Subscribe Now! |