We’ve focused on states of matter and transformations between then for a some time now. Previous posts can be found here. We have looked at solids, liquids and gases and transformations between solids and liquids. Finally we will look at transformations between liquid and gas.
I’ve often had daughter with me as I cook. It is an excellent opportunity to teach her about how water (liquid) turns into water vapour (gas) when we add heat. This is a good way to introduce the topic. Just heat water in a pot and when water vapour starts to rise out of the pot, explain that the liquid is turning into a gas because we add heat. This is also an opportunity to teach that this water vapour is the same stuff that forms clouds and fog. They are also instances where water has turned into vapour.
Once the concept was fairly established, we did an experiment. We created a cloud in a bottle. We looked at the instructions here provided by Wikihow. I chose the one I thought would be easiest with my daughter and allow her to participate as well. Stuff needed are a bottle, some water, and a match.
- Put some warm water into the bottle. The warmth helps water molecules to escape the liquid form and become water vapour.
- Light a match and drop it into the bottle. The impurities this brings into the bottle help the cloud form as the water vapour condenses around the little impurities caused by the burning match. This creates the cloud.
- Close the bottle tightly to stop the cloud from escaping.
- Press the sides of the bottle a few times. This changes the air pressure inside the bottle and helps the cloud form
- Watch as a cloud is formed.
- Wait a bit and see how the vapour condenses on the sides of the bottle. This happens as the air inside cools down and water vapour condenses once again into liquid.
I chose this method as it is quite simple and easy to do. Daughter could help with step 4 especially. Adults are needed especially in step 2. These concepts are fairly well established around our house, but I explained every step to daughter as we did this. As the cloud formed, I again explained how this is the same stuff that can be found in fog and clouds. We returned a few times to note the condensation.
Later we will experiment with solar power, vaporisation and condensation.
If you try these experiments at home and your child asks questions, please let me know what types of questions they ask in the comment section so I can further develop these instructions. If you have questions about these experiments or instructions, leave me a comment and I will answer and also improve these instructions. Also, please remember like and share if you find this useful.
Copyright text and images: Satu Korhonen. You are free to try these experiments out, use them in your teaching. But instead of copying the text or images, link back to this page.