Simple 6th, 7th, 8th Grade Science Fair Project


This is a simple science fair project to show how water expands when it's heated. So basically we're going to take a plastic bottle, fill it with some water, add some food coloring, and then we put a straw through the bottle cap down into the water. After that will take lamp and shine it on on the bottle, and the water warm up. If the water expands, if it undergoes thermal expansion, its gonna have to go somewhere and up the straw is the only option it has. So our data is going to be how much the water rises in the straw. Pretty simple right? But to really impress the judges at a Science Fair or to impress your science teacher at school, you need to have a topic that's interesting and important. And this is why thermal expansion water is important. There's a lot of water on our planet fact about seventy percent of the earth is covered by water. So if the average temperature on earth increases, then the water is going to expand and will occupy more volume.

But like the water in the bottle it has to go somewhere and that somewhere is over islands in up the coast. This is what we call sea level rise sea level rise. It is a slow process but it's happening right now and the sea will continue to rise and thermal expansion water is a major factor in sea level rise. So that's what makes this project interesting and important and that's what will make your work stand out, because many people don't realize that thermal expansion is an important factor in rising sea levels. So my hypothesis might be: If water is heated then it will expand occupied more volume. And then I could test that. So to test that I took a 750 milliliter Dr. Pepper bottle, a two liter bottle would work as well, and I drilled a hole in the cap of the bottle so straw just squeezes through. Then I sealed around the bottle cap to make sure that no water could leak out. I used a hot glue gun but caulk or waterproof sealant work just as well.

So I filled my bottle of water, I put in some dark food coloring, and then I put the cap on. Make sure that the water is up a little bit in the straw. Before I turned the lamp on, I collected data as to how high the water was in the straw. Then I shiny incandescent bulb, those are the one's that get hot, on the bottle. You could use a thermometer in the bottle if you want to collect temperature data. But to minimize materials I just measured how high the water went in the straw and I did that every 15 minutes. So here's a few data points: we have our initial data point before we turn the light on 15 minutes, 30 minutes 60 minutes and then all the way up to two hours. At that point I had to stop because it was about to overflow. Two things to note: one is it nothing happens, you turn the light on and the water doesn't rise, you probably have a leak. So you want to make sure that there are no leaks, even a tiny leak can cause problems.

The other thing is you may want to have a control group. This is an identical bottle with a straw and the bottle cap and the food color and water, but you don't put it under the lamp. You still collect data, but it shows you that if nothing happens in the control, that the lamp is really what's causing the water to get warmer and to expand. You should follow the format provided by the science fair or by your teacher to write the project up. But remember what's interesting here, in addition to your data and how you present that, are the implications for your project. If you can discuss how sea level rise relates to the work that you've done, how your bottle with a straw and the water is a model for sea-level rise, that will really make you work stand out.

This is Dr. B, and thanks for watching. .