You might wondered how to separate water into hydrogen and oxygen. Maybe you even thought how to produce oxygen aboard a submarine . This lesson is for you!
This experiment is related to electrolysis of water. Using battery and copper wire, we can split water into hydrogen and oxygen. What is more interesting we see that flame is brighter whenever we are getting our candle closer to pure oxygen. Therefore, it is a fantastic introduction of science and physics for preschoolers.
After all, please leave your comments below. I am curious how it goes for you.
In our experiment we used:
Due to the fact that hydrogen and oxygen are very reactive and flammable, please take special precautions:
work in distance from flammable things (wood, LPG kitchens, papers, curtains and so on)
be ready to fade out potential fire
use glasses at all time
keep your hair tied up
do not breath the gases (especially chlorine)
Step 1 – Prepare container
Firstly, take a water container. We prefer the flat one because it is easier to manipulate with copper wires and a candle. Additionally, flat container is more stable and therefore more secure.
Step 2 – Pour the water and add salt
In the step 2 we take water and fill the container with it. We are adding kitchen salt into the water as a result your water and salt solution should be around 10%. In conclusion it means following proportions: 90 grams of water and 10 grams of salt. For your convenience we prepared a table so you can quickly adjust the amounts.
Amount of water (g)Amount of salt (g)90101802045050
Step 3 – Prepare the battery and wires
Now the electric part. Prepare 9V battery (the cuboid one). To be honest it can be whatever shape you like, but this one stands firmly and it is relatively easy to connect the copper wires into it. In addition to that, prepare two separate strings of a copper wire, ca. 30 cm each. They need to be long enough so you can make a firm connection with the battery, make twirled ends that go into the water and salt solution and hang them over the container.
Make sure that they are long enough so when in the water, you can keep the distance between them. In other words, the ends of the wires cannot touch each other.
Step 4 – Connect the wires to the battery
Above all, to make the experiment go, we have to connect the wires to the battery. As a result, one string of wire goes into the “+” and the other string is connected to “-“.
Step 5 – Place the wires in the water container
Now the best part. Once you place the wires into the water reaction starts immediately. Due to the electric current you can observe bubbles (hydrogen, oxygen) and kind of blue/green substance (chlorine).
Step 6 – Observe the results
Congratulations! You have just made a simple generator of oxygen and hydrogen. In addition, you can check the reaction of oxygen / hydrogen with a candle. Therefore, lit a candle and gently get closer and closer over the place where bubbles are coming out from the water. What do you see? Is the light lighter?