According to Reeko's Mad Scientist Lab, a simple project using a peeled boiled egg, a plastic bottle with a long narrow neck just small enough to keep an egg out and matches can demonstrate expansion. First, gently attempt to put the egg through the mouth of the bottle. After observing that it won't quite fit, pull back the egg and place three lit matches inside the bottle. Quickly place the egg into the mouth of the bottle and observe the egg being "sucked" inside the bottle.
The lit matches heat the air inside the bottle; the hot air is forced up and out through the mouth. This process initially creates an increase in pressure inside the bottle. Once the matches are out, however, the air inside the bottle immediately cools, creating a difference between the pressure inside the bottle and the pressure outside of the bottle. Because of the lower pressure inside the bottle, the egg will be sucked inside.
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WIth 9 ounces of water, a pan, a candle that will stand upright, and a glass vase, you can see the effects of expansion and contraction, according to Steve Spangler Science. Pour the water into the pan. Then place the candle in the middle of the pan and light it. Cover the still-burning candle with the vase.
The air inside the vase heats up, expands and escapes, making the water bubble. When the candle flame goes out, the air inside the vase immediately cools and contracts, creating a vacuum and that pulls some of the water molecules into the vase. The contracted gas inside the vase has a low pressure, compared to the gases outside of the vase. This pressure differential creates the vacuum effect.
Wood is created from a tree, which is an organism composed mainly of water. Wood contracts and expands based on thermal and humidity differences in the air around it, according to All Science Fare Projects. Higher humidity in the air around wood creates expansion of the wood, while lower humidity creates contraction, or shrinking.
A science project using different types of wood like redwood, oak and maple will demonstrate expansion and contraction. When the wood is placed into an oven on low heat, the pieces of wood contract in varying degrees, depending on their water content. The pieces of wood become smaller because the water inside the wood is converted into a gas called vapor. The vapor is created by the expansion of water molecules that results from an increase in heat.
A bowl, a bottle and a balloon filled alternately with hot and cold water can be used to demonstrate expansion and contraction. Fill the bottle with hot water and the bowl with cold water. Let both sit for 1 minute and then empty the bottle. Stretch the opening of the balloon to cover the mouth of the bottle. Then set the bottle in the cold water.
The results of the experiment are as follows. The hot water heats the bottle. When the water is poured out, the hot bottle heats the air that flows inside. Placing the bottle in the cold water then cools the air, so it contracts. The balloon is pulled and then inflated inside the bottle.