 Welcome back to Kids Fun Science. My name is Ken. Today's experiment is the homemade water thermometer. As always adult supervision is required. What you need for this experiment is a stove, a drill, a jar, a pan, a straw, and some food coloring. So to set up this experiment you need a jar with a lid and so I've got my jar, a little canning jar, and take the lid off there and then I'm going to drill a hole in the lid the same size as the straw. You don't want it bigger than a straw so you want it the same size. So make sure you size that out and depending on your size of your straw and then once you have the hole there you're going to put it back onto the jar after we fill it up. So we step in I fill the jar up full with water you want it almost to the top if not to the top add food coloring and I know I'm adding blue and I'm doing a hot experiment I should be adding red for the color effects but blue was the only one I had so I went with it and so I apologize on that but you'll still get the same idea and see how it works so go ahead once you get the food coloring in screw the lid on and then we're going to take the straw and it helps to have a clear straw so you want to be able to put that in it should be very tight if you have the right drill bit and put that all the way to the bottom you'll see here the straw very hard to see I move it back and forth you kind of see it moving a little the straw's got to touch the bottom of the glass so once you get that there then we're going to turn the stove on high we're going to put a pan half full of water and so it's on high and then we're going to take our jar and put it in the middle and and then we're going to observe now we're going to sit back and observe the homemade water thermometer but while I'm doing that I'm going to explain the science behind it so as water is heated its molecules move faster right so causing them to spread farther apart from one another and as a result the heated water expands causing the water to rise in the straw because it has nowhere else to go right so the thermometer works according to the same principle right so as the liquid which is in regular thermometers mercury or alcohol is heated it they expand and they rise as it cools it contracts and falls back down so as you see is the water starting to get hotter and hotter we're going to notice that the water the hot water is going to expand and it's going to only place it can go up the straw that's why we need to have a clear straw so we can see how the thermometer works so this is a really fun one to do at home just be very careful as the water is extremely hot and you can burn yourself in the jar and then the jar itself and the water in the pan as it continues to get hotter it's going to expand more and more so it's a really awesome experiment and once it gets to the top it will have nowhere else to go but out of the straw so that's pretty fun to watch too so continue to watch is going to go up i hope you enjoyed this video remember to click thumbs up and to subscribe and thanks for watching