What is an Experiment

Lots of science fair projects are suppose to have an experiment as part of the project, but exactly is an experiment?

Continue reading "What is an Experiment"

Experiments are one way to answer questions.  If your child asks you "How long does it take for an ice cube to melt?", the two of you can do an experiment to find out.  Take an ice cube out the freezer, put it in a bowl on the counter and time how long it takes to melt.  That's the simplest type of experiment where you are watching a phenomenon.

That basic experiment can lead to more questions and more advanced experiments.  After watching the ice cube melt, most kids will start to ask more questions.  What could we have done to make the ice cube melt faster?  What would make it melt slower?

One option at this point is to take a moment and create a hypothesis about ice cubes and melting.  Another option is just to help your child set up a series of tests.

Whether you are creating a science fair project, using a hypothesis or just experiment for fun, let's define a few of the terms.

Independent variable - something that is changed in the experiment.

Dependent variable - something that responds to the Independent variable.

Constant Variable - something that is kept the same throughout the series of experiments.

Control - similar test where the independent variable is left unchanged to provide a comparison.

To continue with our ice cube melting experiment,  the next question might be "Would the ice cube melt faster if it was in little pieces?"  You could set-up a test where you have one ice cube that is broken into little pieces on one plate, and a whole ice cube on a plate beside it.  Then you would time how long it takes each ice cube to turn into water.

The independent variable is the size of the pieces of ice, it changed between the two tests.  One of the constant variables would be the temperature in the room, it stays the same for both tests.  The control would be the whole ice cube that is melting.  The dependent variable would be the time it takes the ice cube to melt.  That variable is dependent on the size of the pieces of ice.

What if you had just taken out one ice cube, broken it into small pieces and timed how long it took to melt?  Couldn't you have just compared it to the time it took the first ice cube to melt?  Maybe.  But the temperature in the room might have changed between the two experiments.  By having a control (the whole ice cube) you are trying to control for other variables that aren't part of the experiment (temperature) but that could change your results.

If your child is planning a series of experiments, the constant variable could become the independent variable in the next experiment.  It just depends on the question you are trying to answer and the design of the experiment.

Kids should be encouraged to just experiment in the beginning.  But as they find out how fun and interesting it is to do science experiments, start to introduce some of the scientific principles and terms.

A control is often the most interesting part of the experiment.  Often they will surprise the scientist by behaving different from what was expected.

Experiments for a science fair need to follow a specific set of guidelines.  The guidelines can vary between science fairs so be sure you have the correct information.

Notes to Parents:

1. Every parent must use their own judgment in choosing which activities are safe for their own children.  While Science Kids at Home makes every effort to provide activity ideas that are safe and fun for children it is your responsibility to choose the activities that are safe in your own home.
2. Science Kids at Home has checked the external web links on this page that we created.  We believe these links provide interesting information that is appropriate for kids.  However, the internet is a constantly changing place and these links may not work or the external web site may have changed.  We also have no control over the "Ads by Google" links, but these should be related to kids science and crafts.  You are responsible for supervising your own children.  If you ever find a link that you feel is inappropriate, please let us know.

Send us a note if you have any questions.