In this lesson, we will investigate the different steps involved in an experiment. Let's start by learning about experiments.

An experiment is a scientific test where you perform a series of actions and carefully observe what happens in order to learn about something. For example, if you want to test to see if water freezes faster than soda, you can conduct an experiment where you put an equal measurement of water and soda in a freezer and observe which liquid turns to solid faster.

How do scientists make guesses about the world based on their findings?

The information or data we collect from this experiment would be called our findings. We call the information we learn from an experiment a finding because, in science, you look for information and then you find it.

One very important point: an experiment must be able to be replicated. That means someone else must be able to do the same thing you did and in the same way that you did it. If the experiment is replicated and the other scientists observed the same thing that you observed, then you have found good, strong evidence.

This is how science works. A scientist or group of scientists does an experiment that produces a finding. In other words, they find the information they were looking for. Then, another scientist or group of scientists replicate the first experiment. That means they do the same thing in the same way and then observe it to see if the same results happen. If it does, they have a finding that supports the first experiment. If the result is different, well, that's a finding too. It is evidence that they need to look at the question more in order to find the answer.

Let's try an experiment to see how it works. And when we do the experiment, you should pay close attention to what we are doing in each step and how we are doing it. That way, if you want to replicate it at home, you will be able to.

In this experiment, we're going to try to explain why the Earth is getting warmer. In our experiment, we will observe two jars.

Each jar will represent a different model of the earth's atmosphere. An atmosphere, as we remember from an earlier video, is defined as the layer of gases surrounding a planet. In our course, we are talking about the atmosphere around the planet Earth.

Jar A will represent the Earth's atmosphere in its most basic form. That means we don't do anything to change what it is. Jar B will also represent the Earth's atmosphere, but it will be covered at the top with clear plastic wrap and a rubber band. This change in the jar is called an independent variable. An independent variable is a thing changed by scientists to measure differences in an experiment.

So, what's different here?

When the jar is open, the air can flow in and out of the jar. If the jar is covered, nothing can go in or out. So we want to observe what happens to the temperature of the jar when the air cannot go in and out of the jar. And remember, Jar A will represent the Earth's atmosphere in its most basic form. It will be our control in the experiment. A control in a scientific experiment is the thing that scientists do not change so they can compare results.

Image Credits:

1. “Replicate” by FHI 360 is a derivative of "Image " by Mohamed Hassan (Links to an external site.) under Pixabay license. This derivative is licensed CC BY 4.0 by FHI 360 for use in the OPEN Program, sponsored by the U.S. Department of State with funding provided by the U.S. government and administered by FHI 360.

2. "Warming Experiment Jars" This work is a derivative of "Untitled Image" by the University of Pennsylvania, used under CC BY-SA . This derivative is licensed under CC BY-SA by FHI 360 for use in the OPEN program, sponsored by the U.S. Department of State with funding provided by the U.S. government and administered by FHI 360.

3. "Atmosphere" ISS063-E-065220 " by Expedition 63 Crew via NASA Earth Observatory is under Public Domain / US Government Works