Student teams investigate the migration of small-particle plastic pollution by exposing invertebrates found in water samples from a local lake or river to fluorescent bead fragments in a controlled environment of their own designs. Students begin by reviewing the composition of food webs and considering the ethics of studies on live organisms. In their model microcosms, they set up a food web so as to trace the microbead migration from one invertebrate species to another. Students use blacklights and microscopes to observe and quantify their experimental results. They develop diagrams that explain their investigations—modeling the ecological impacts of microplastics.

Students work as engineers to design and test trebuchets (in this case LEGO® MINDSTORMS® robots) that can launch objects. During the testing stage, they change one variable at a time to study its effect on the outcome of their designs. Specifically, they determine how far objects travel depending on their weights. As students learn about the different components of robot design and the specific function controls, they determine what design features are important for launching objects.

Try this experiment around your yard or school and see how biodiversity at the plant level affects biodiversity at the insect level.

Discover how to figure out all the possible outcomes when performing an experiment by following along with this tutorial. [4:18]

Simulators are a great way to model an experiment without actually performing the experiment in real life. This tutorial looks at using a simulator to figure out what might happen if you randomly guessed on a true/false quiz. [7:13]

The outcome of an experiment is any possible result of the experiment and is a very important part. Learn about outcomes by watching this tutorial. [2:10]

Students conduct a simple test to determine how many drops of each of three liquids water, rubbing alcohol, vegetable oil can be placed on a penny before spilling over. Because of their different surface tensions, more water can be piled on top of a penny than either of the other two liquids. However, the main point of the activity is for students to come up with an explanation for their observations about the different amounts of liquids a penny can hold. To do this, they create hypotheses that explain their observations, and because middle school students are not likely to have prior knowledge of the property of surface tension, their hypotheses are not likely to include this idea. Then they are asked to come up with ways to test their hypotheses, although they do not need to actually conduct these tests as part of this activity.