Over the last couple weeks, we’ve done a bunch of water experiments. We filled a jar to the brim with water and then put it in a pot with a couple inches of water and boiled it. The water overflowed from the jar because hot water expands.
We put ice in a cup of water. The ice floated because ice is less dense than liquid water.
We put a cup filled to the brim with water in the refrigerator. As it cooled, the water level went down because cold water contracts. We put another cup filled to the brim with water and capped with a piece of cardboard in the freezer. The cardboard cap was pushed up and formed stalactites as the water froze because water expands when it freezes.
We made a water cycle. We put a small mixing bowl weighted down with a rock in the middle of a larger mixing bowl. In the bottom of the large mixing bowl we added a couple inches of water. We covered the large bowl with plastic wrap and weighted it down with a rock so the lowest part of the plastic wrap was directly over the small bowl. We then placed it in the sun. Before long we could see the water had evaporated and then condensed on the plastic wrap. Within a couple days quite a bit of condensed water had “rained” into the small bowl.
We crushed a piece of chalk and added it to water. We filtered the solids out of the chalk water by running it through a handkerchief. This made very hard water. We put some water in each of two baby food jars and added washing soda to one of them to soften that water (the washing soda also made the water heat up). We added a tablespoon of soap powder to each of the jars of water and shook them up. The soft water produced more bubbles and the bubbles lasted longer than the hard water.
We filled a can with ice water. We added food coloring to the water. After a couple minutes, water droplets appeared on the outside of the can. These droplets were clear so they did not come from the water inside of the can. This is because the droplets came out of the water in the air.
We put an egg in a glass of water. It sank. We dissolved lots of salt in the water and the egg began to float. This is because salt water is denser than fresh water.
We did some water evaporation experiments. We put the same amount of water in two baby food jars and left one open and put the top on the other. The water from the open one evaporated faster. We put the same amount of water in two identical plastic containers. We put one in the sun and one in the shade. The one in the sun evaporated faster. We put the same amount of water in an olive jar and in a small plate. The water in the plate evaporated faster.
We wet two identical handkerchiefs. We waved one around and left it to dry under a fan. The other we hung up in a draft-free location. The one under the fan dried much faster.
We completed our hovercraft experiments. This time we used tape and paper and designed our own hovercrafts.
We floated a needle on a bag tag in water. Then we broke the “skin” by touching the water with a bar of soap. Soap reduces surface tension so the water could no longer support anything on top.
We put drops of food coloring in milk. Then we added a few drops of liquid dish soap. The dyed milk immediately started swirling.