What’s a constant in an experiment, and why is it important? Do you need a constant when performing science experiments? Can the constant change? Let’s find out!
Constants in Experiments
Have you ever done a science experiment? Maybe you’ve done one at school in science class, for a science fair, or just for fun? Experiments are fun because they teach you a lot about how the world around you works.
When doing science experiments, there are different parts of the experiment that must be included for the results to be accurate and valid.Science experiments usually include an independent variable, dependent variable, and control. Remember, an independent variable is the part of the experiment the scientist changes or controls. The dependent variable is the part of the experiment that reacts to the independent variable. The control is the base experiment for comparison with other trials of the experiment.
Science experiments also include something called constants. A constant is the part that doesn’t change during the experiment.
Using a Constant
Let’s apply these parts in an example experiment.
Say we want to know how long it takes an ice cube to melt. You can easily perform this experiment by putting an ice cube in a bowl on your kitchen counter and timing how long it takes to melt. This base experiment (the ice cube melting at room temperature) becomes your control, and different outcomes will be compared to this control.Now say we want to see how long it takes an ice cube to melt at different temperatures. This time, we put one ice cube outside in the sun and one in the fridge.
Changing the temperature will affect how long the ice takes to melt. Since the temperature changes, temperature is the independent variable.The amount of time it takes the ice cube to melt is the dependent variable, because this will change based on the independent variable. The constant in this experiment is the ice cube: it is the same size – at least at first – in each trial of the experiment.
What Else Can Be a Constant?
A constant must stay the same throughout the experiment.
However, the constant can be many different aspects of the experiment.In our ice cube experiment, the constant was the size of the ice cube. But what if we want to know how long different sizes of ice cubes take to melt? This time, we’re going to leave one regular-sized ice cube and one small ice-cube on the counter to melt. This time, the independent variable is the size of the ice cube. The dependent variable is the time it takes to melt. And the constant is the temperature, since the temperature stays the same throughout.
Can You Determine the Constant?
Now, let’s think about yet another version of the ice cube experiment. This time, we want to know how long it takes different frozen liquids, soda and juice, to melt. Think about the answers to these questions:
Okay, let’s see if you’re right!The independent variable is the type of liquid: soda or juice – you change this variable in each trial.
The dependent variable is the time it takes the different liquids to melt: the time depends on the independent variable (the type of liquid). And, the constant is the size of the frozen cube of liquid. Whether it’s soda or juice, the cube must be the same size for the results of the experiment to be valid.
There are many different parts of an experiment, and it’s important to understand them in order for experiment results to be valid and usable. You must pay attention to the control, independent variable, and dependent variable as well as the constant, which is the part that doesn’t change during the experiment.