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Hunt for Alien Worlds

Classroom Activity

Objective
To make inferences about an object hidden inside a sealed box.

• copy of "Black Box Mystery" student handout (PDF or HTML)
• box with unknown object inside

1. Using indirect methods, scientists collect evidence to infer the presence of planets they can't see or visit. In this activity, students collect evidence to make inferences about an object hidden inside a sealed box.

2. Create each mystery box by placing a common classroom object (such as a roll of tape, scissors, or a beaker) inside a box and sealing it with tape or a rubber band.

3. Set up a table that displays 10 to 15 common classroom objects, some of which are similar to or exactly the same as the objects in the mystery boxes. Provide additional empty boxes as well.

4. Organize students into groups and distribute the "Black Box Mystery" student handout and a mystery box to each group. Explain that the challenge is to design ways to gather information about a mystery object that students can't see or test directly.

5. Point out that the mystery objects are similar to some of the objects on the display table. Students can use information they know about these objects to help them learn more about the unknown mystery objects.

6. After they've completed the activity, have students compare the process of inferring the identity of a mystery object sealed in a box to inferring the existence of a planet in distant space. Then have groups consider how inference plays a role in their daily lives. Explore group answers in a whole-class discussion.

Students will design a variety of tests to gather information about the mystery object. For example, they might determine the weight of the object by comparing the weight of the mystery box to the weight of an empty box. They might shake the box and listen to the sound the object makes. Or they might try to determine the object's shape by the way it strikes different points of the box when shaken. They could then take a known object from the display table and put it through similar tests. Students might also rule out objects that are unlikely or impossible, such as objects that are too large to fit in the box.

If students arrive at immediate conclusions, direct them to return to the evidence by asking questions like How do you know that? Remind students to evaluate their inferences by comparing them to the evidence they've collected. Inferences that don't include all of the evidence are not necessarily wrong, but may be less believable. Point out that there is a range of plausible explanations, some being more likely than others.

Discuss with students whether the real identity of the mystery object should be revealed. By not allowing students to see what the object is at the end, the focus of the activity remains not on getting the right answer, but on developing plausible inferences, or conclusions, that are supported by evidence.

An example of a daily life inference might involve inferring whether someone is in the bathroom. Evidence such as a closed door, the sound of running water, and a bathrobe missing from a sibling's bedroom could be used to infer that someone is in the bathroom.