The good news is that many times, a model can be used in an experiment, and variables can be added to a demonstration, so that it can be one, too. Here are five examples of projects that are modified to become an experiment.

- How hot can a solar heater get? – First of all, finding the answer to this question may result in a fire! Make it an experiment by testing two different solar heater models. Construct two identical heaters, one with a glass front, and the other with a plexiglass front. (The instructions are live here.) Measure the temperature over several days, and see which one got the hottest.

- How can you make a potato canon? – This is a fun activity, and it demonstrates how cool science can be, but it doesn’t test anything. How can you turn it into an experiment? Vary the trajectory, and ask, “At which angle will a potato canon launch a potato the farthest?”

- What happens when you mix chalk and lemon juice? – Studying acids and bases is fascinating, but there are no variables – so it’s not an experiment. Change it up. Soak pieces of chalk in water, a basic solution, and an acid, and note the variance in the weight.

- What happens when bean seeds germinate? – This is a great lesson, but what are kids comparing? Turn it into an experiment by testing “At which temperature do bean seeds germinate the best?” Use different watt bulbs to vary the temperature.

- How do bones change when soaked in vinegar? – This is close to an experiment, but the project I saw didn’t have a way to measure the change. The results of a true experiment must be measurable. Come up with a weigh to measure the amount of weight the bones can support before breaking, and you may just win your middle school science fair.

Remember, an experiment is a test of the relationship between two variables that have measurable results that can be replicated. It amazes me that reputable science publications will label any sort of science activity as an experiment. It doesn’t matter that you’re still in middle school type of project isn’t right. You can do better than ‘real’ scientists! Turn a ‘non-experiments’ into middle school projects that will amaze judges, your teachers – and yourself!

If you’re looking for a ready made experiment, get one of our Science Project guides. They’ll take you step by step through the experiments, all of which follow the scientific method.

Here are some things I’ve found that are great science fair topics, but simply are not science experiments:

~ Making a Potato Canon - This is a fun activity, and it demonstrates how cool science can be, but it doesn’t tst anything. How can you turn it into an experiment? Vary the trajectory, and ask, “At which angle will a potato canon launch a potato the farthest?”

~ What happens when seeds germinate?” – This is listed as an experiment on a teachers’ forum. Can’t believe it. It’s a great lesson, but what are kids comparing here?! Turn it into an experiment by testing “At which temperature do seeds germinate the best?”

~ How do bones change when soaked in vinegar? – This is close to an experiment, but the project I saw didn’t have a way to measure the change. The results of a true experiment must be measurable. If your kids come up with a weigh to measure the amount of weight the bones can support before breaking – you may just have a winning kids science experiment.

That gives me a great idea for another science project experiment, actually…Stay tuned!

PS ALL of the projects at 24 Hour Science Projects are experiment based – Hypothesis, Variables, Measurable Results and all!

Here’s my response: Remember, an Independent variable is what “I” change. So in this experiment, the independent variable would be the types of fruit. The dependent variable is what changes because of the independent variable (the type of fruit). And since the number of drops depends on the type of fruit, that would be the dependent variable.

Another example, from our guide:

Variables – When doing a science experiment, there are things that you, as the scientist, control to make sure your test results are dependable:
• Independent Variable – The independent variable is the thing that you change in the experiment. All the other things in your experiment should stay the same. For example, in our experiment the independent variable is the type of fertilizer. We’ll use the same kind of pot, soil, and plant. We’ll have the plants get the same amount of light and stay in the same room at the same temperature. We’ll add the same amount of water. The only thing that will change is the kind of fertilizer.
• Dependent Variable – The dependent variable is the thing that changes because of the independent variable. For us, that would be the height of the plant. The height of the plant changed because we changed the type of fertilizer.
• Control – The Control is the group in which nothing changes at all. In the fertilizer experiment, that would be the group of plants that only was given water with no fertilizer.

For more information – including step by step instructions – on this project, check out 24 Hour Science Projects.