Hello everyone, welcome back to my blog. Today in science, we did a contraction experiment.
In this experiment, we set up our Bunsen burner with the following equipment: a heatproof mat, a Bunsen burner, a tripod, a gauze mat, tongs, a soda can filled with 100 mL of water, and an ice cream tub filled with cold water.
In this blog, I will give a method, show a video of what happened, explain what happened to the can, and describe why this happened.
Method –
- We got a soda can and filled it up with 100mL of water.
- Get an ice cream bucket and fill it with cold water (add ice if you want it to be colder).
- We set up the Bunsen burner, with a heat-proof mat underneath the tripod and a gauze mat as well.
- We placed the can on top of the Bunsen burner, which is on the blue flame.
- As it started to boil and we could see steam, we grabbed some tongs and firmly gripped the soda can.
- After gripping the can, making sure it won’t fall, quickly flip the can into the cold water.
- Once the cold and hot water collide, the can will shrink because there is more air pressure outside pressing the can inwards.
Video –
What happened to the can?
When we heated the can on the Bunsen burner, the water inside the can started to boil, and we could see the steam coming out from the top. After the water boiled for a while, we used tongs to quickly turn the can upside down and place it into the tub of cold water.
As soon as the hot can touched the cold water, the can suddenly crushed and crumpled inwards. It looked like the can was being squashed without anyone touching it. The sides were pushed in, and the can became dented and smaller than before.
Why did this happen to the can?
This happened to the can because when we heated it, the water inside gained heat energy and its particles moved faster, turning into water vapour that pushed most of the air particles out of the can; then, when the hot can was suddenly placed in the cold water, the water inside quickly lost heat and its particles slowed down and condensed back into liquid, which took up much less space, so there were far fewer gas particles inside the can, creating a much lower pressure than the air pressure outside, and because the outside air particles were now pushing harder on the can than the inside particles, the can was crushed inwards by the air pressure.