Another experiment for that budding scientist within you. This time: A very simple experiment, in which you make your own rocket!
Hopefully you all tried out the experiment posted a couple of weeks ago. If not, you can check that article out here, where I tell you how you can make your very own volcano.
Today’s Experiment: Fire a Rocket!
What you will need:
– A 1l plastic bottle, empty
– A piece of cardboard
– A cork, the same size as the opening of your bottle
– A air pump with a needle on the end of it
What you need to do:
– Push the needle on the end of the pump through the cork
– Make fins and a nose cone out the cardboard and attach them to the bottle
– Fill the bottle a quarter full with water and push the cork, complete with needle, into the opening, ensuring no water escapes
– Make sure the bottle is in an open space outside and set the bottle up, sitting on its fins if possible
– Stand back, and pump air into the bottle. After a bit, the bottle will lift off with its own force. We have liftoff!
Try changing how pointy the nose cone is, or change the shape and size of the fins. Mess around with how many fins there are on the bottle. Try and get the rocket to fly straight up, or see if you can get it to go to one side depending on the orientation of the fins. Remember to only change one things at a time though!
The science behind the experiment:
Whereas last time was more of a chemistry experiment, this one focusses more on physics.
Everything takes up space. You, me, water, air, everything. How much space a thing takes up is dictated by how dense it is. Solids are pretty dense – you can get a lot of a solid in a small space. Liquids aren’t quite as dense, whereas gases are very spaced out. However, when you force enough of a gas into a small enough space, their density doesn’t change, but the pressure does. Pressure is a force that pushes against whatever is pushing it. So when air is forced into a small space (the bottle), the force that is pushing against the bottle (pressure) increases. When the pressure goes above a certain point, the water forces the cork out of the bottom of the bottle.
Isaac Newton created three ‘laws of motion’ that explain how all objects move. His third law dictates that
“for every action there is an equal and opposite reaction”
This explains why the water being pushed down produces a force going up, that lifts the rocket into the air.