When do children understand that “invisible things” can affect objects?

    • Topic: Cognitive Development

    • Location: Discovery Center

    Preschoolers understand that some objects have internal properties that produce predictable and observable effects on other objects. Yet, in their everyday lives, children also hear about things they cannot see (e.g., germs, air), but that have observable effects. In this study, we are interested in when and how young children come to understand the causal properties of such invisible things.

    Young children are shown a special box that changes color when a researcher places either a small object or an “invisible substance” on the box. Children see how different objects and “substances” change the color of the box, and are asked to explain what caused the box color to change. The researcher also presents children with an object that appears to be another object (e.g., a candle that looks like a crayon) to help researchers determine whether children understand that an object can appear to be something different than what it is.

    We predict that, by 3 years of age, children will understand, and be able to explain, that both objects and “invisible substances” cause the lights on the box to change color. We also predict that children who understand that appearances can be deceiving (e.g., a candle that looks like a crayon is still a candle) will also be more likely to understand that events may be caused by things they cannot see (e.g., germs, air).

    This research will help us better understand when and how children come to understand causal relationships that involve things they cannot directly observe.

    This research is conducted at the Museum of Science, Boston by the Paul Harris Laboratory at the Harvard Graduate School of Education

        » Paul Harris Laboratory at the Harvard Graduate School of Education

    Activities to Try in the Discovery Center

    What’s in there?

    Find the Air Table in the Physical Sciences Area of the Discovery Center. Place a pipe over one of the holes in the table so that air is flowing through. Place a ball on the pipe and show your child that the ball floats. Move the pipe so that it is no longer sitting over one of the holes. Place a ball on the pipe and show your child that the ball does not float anymore. Ask: “What happened? Can you make the ball float again?” Help your child move the pipe back and forth – can s/he figure out what is making the ball float?

    Activities to Try at Home

    Lights, Camera, Action!

    Find a flashlight, sit with your child in a dimly lit room, and play a guessing game. Turn the flashlight off, but aim it toward a wall. Ask your child to go and put their hand on the wall at the place where they think the light spot will be when the light is turned on. Turn the flashlight on, and see how close your child’s guess was. Take turns pointing the flashlight, and guessing where the light spot will be.

    After playing a few times, ask your child: “How can we tell where the spot will be? Is there any light between the flashlight and the spot on the wall?” Encourage your child to walk around to explore this question by looking at it from different angles. We can see light when we look directly at the source (the flashlight), or it bounces off of something (like a wall), but as the light moves through the air it seems to be invisible. From what angle can s/he see the light the best? Are there any places in the room from which s/he cannot see the light?

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