Back to school science begins with the scientific method. Get your little scientists ready with some simple experiments. They’ll learn how to conduct a fair test. And they’ll have a lot of fun!
The Scientific Method?
Actually, no one scientific method exists. Scientists follow a general set of steps. But they vary. Your students need to know this up front. I use these cute posters to get my kids thinking. We discuss their interchangeable nature. For example, the process itself can be called the scientific method, scientific inquiry, scientific experimentation, etc.
Teach these steps. But emphasize the fact that they can be changed and rearranged.
- Ask a Question – First, wonder! What do you want to know?
- Conduct Research – Next, look on the Internet to see what others have found. (Sometimes, in fourth grade, we skip this step. It makes life more interesting.)
- Hypothesize – Now it’s time to make an educated guess. What do we think the conclusion will be?
- Design a Fair Test/Design an Experiment/Test the Hypothesis – This is the meat of the process. Look below to find out what every good experiment needs.
- Make Observations – Once the experiment gets started, use your senses. Look. Feel. Smell. Listen. Write it all down.
- Collect Data/Record Results – Measure. I can’t emphasize this enough. Something must measured. Observations alone are too subjective. You need numbers.
- Draw Conclusions – What does all of this mean? Have I found an answer to my question? Or do I need more investigation?
- Share Results/Communicate – Tell others. Write it down. Make a poster. Share it on the Internet. Just do something to let others know what you learned.
I reinforce all of this with a PowerPoint presentation.
The Fair Test
Let’s just say it. If you don’t do all of these things, it’s not a fair test. In fact, it’s not really an experiment.
- Compare – This is your variable. One thing (and I mean ONE thing) needs to be varied and compared. For example, in the first experiment below, we are comparing covered water with uncovered water.
- Control Variables – What does this mean? Everything else needs to be the same. Same cups. Same temperature. Same humidity. Same, same, same! When you talk to your kids about controlling variables, emphasize that word: same.
- Scientific Tools – Eyeballing is not good enough. Your kids need to measure. They should know what these tools are and how to use them. Note: One cubic centimeter equals one milliliter. One milliliter of water has a mass of one gram.
- Ruler/Meter Stick/Tape Measure – measures length (centimeters)
- Balance Scale – measures mass (grams)
- Graduated Cylinder – measures volume (milliliters)
- Replicate – To trust your results, you have to do the experiment more than once. The more times you do it, the more you can trust it.
Back to School Science Experiment 1
No simpler experiment exists! You only need cups, water, graduated cylinders, and plastic wrap.
Variations on Experiment 1
Let’s take a look at two variations on this experiment. They’re simple too!
- Salt Water Versus Fresh Water – In a separate container, dissolve 7 cubic centimeters (same as 7 milliliters) salt into 200 milliliters of water. This gives you the same concentration as sea water. Next, measure 50 milliliters of salt water into one cup. Put 50 milliliters of fresh water in the other. Wait two or more days. Compare.
- Sunny Versus Dark – Measure 50 milliliters of water into two cups. Put one in a dark place (like the closet). Place the other in a sunny place (like the windowsill). Wait two (or more) days. Compare.
Back to School Science Experiment 2
In my classroom, we’ve tried growing plants from roots and stems. But this was just exploration. This year, I’m turning it into a fair test!
Question – Which plant parts will grow the largest plants in two weeks?