This week we are looking at “Condensation” as part of our Science at Home experiment. I love how Anthea from Blue Bear Wood has encouraged me to just use “big words” with the kids, to give them a chance to learn them… and not worry about whether something is too complicated or not.
What is Condensation?
Condensation quite simply, is when water vapour (i.e. water that has evaporated and turned into gas) is converted back to water.
We picked the “theme” of Condensation, as we have been going to swimming all week. At our swimming classes, the pool is in housed in a “green house tunnel” type structure. We sit at the pool side and wait for the less to start and get dripped from the ceiling. The Boy asked “why is it dripping Mummy?”.
Heated water: So. I explained to him about how the water in the pool is heated to make it nice and warm for us to swim in.
Evaporation: Some of this water evaporates into the atmosphere (similar to when we boil potatoes and we can see the steam rising from the pot).
Condensation: This evaporated water, hits the roof of the swimming pool building, which is cool, as it is not heated the way the pool is. Which means that the water vapour “landing on it” is also cooled. It forms tiny droplets of water, which then collate (i.e. mix together to make a bigger and bigger droplet of water) until eventually the drop is so big, it drops down on us.
The Condensation Experiment
I wanted to recreate the condensation effect at home.
So I took a glass and place it in the freezer. After about an hour, I took out and placed it outside (it is nice and warm outside at the moment).
1) First the glass went white
2) Then it looked clear and normal
3) But when you touched it all over, it felt wet
4) We even saw a little puddle at the bottom of the glass….
But when we put the glass in the freezer it was totally dry. What happened?
The Condensation Science
This is a little bit of a reverse of what happend of the swimming pool. This time, the water vapour is already in the air (there is always SOME water in the air, which is what we call humidity).
We cooled our glass (similar to the roof at the swimming pool) and brought it out. The glass was colder than the surrounding air. Encouraging the water vapour molecules to cool down and form tiny tiny beads of water – this is why the glass at first looks white… the 1000s of tiny beads of water.
Then, as time when on, the little water droplets got together to make bigger ones, which you could only see if you looked really closely at the glass or you could feel if you touched them. The little puddle is more and more of these droplets forming together to make a small puddle of water.
So the water on the glass and on the table came from the AIR AROUND US and the cold glass caused it to condensate.
I was VERY impressed with Red Ted – I asked him “what do you think has happened, why is the glass wet” and he said “is it condensation, mummy?”. Hurray for good listening skills this morning!