hello boys and girls welcome to who plug kids lab making science super fun and super simple today we're going to show you how to make a balloon barometer a barometer is an instrument used to measure air pressure for this experiment you're going to need scissors a rubber band a jar some tape glue a balloon a needle a straw a pencil a marker pen and some card firstly take your balloon and cut off the neck make sure the opening you're left with is wide enough to stretch all the way around the neck of the jar there we go then stretch the rubber to try and make the surface as flat as possible take your rubber band and place it around the neck of the jar to hold the balloon tight then take your straw cut off the bent section if it has one then cut off a piece of the tape and use it to fix the needle onto the straw then use your glue to fix the straw onto the top of the jar and that's it it's that simple then take your piece of card and using the pen right high at the top of the page and load at the bottom of the page place the jar in front of the paper next to a window and indicate the point that the needle is pointing to you can number this number one then come back after a period of time perhaps an hour or two hours and see where the needle is pointing in this case the needle is pointing higher draw a line next to this point and mark it with a number two the reason that needle is changing height is because air is trapped in the jar when air pressure outside the jar is higher the balloon is pushed in and the needle goes up when the pressure outside is lower the balloon is pushed out and the needle goes down this helps us to know the air pressure outside and how the weather changes and there you have it that's how you make your very own balloon barometer at home come back next time for some more exciting science challenges and share this video with your friends and family and do leave any comments in the box below thanks very much you