Experiment: Sink or Float?

Here’s an oldie but goodie from the archives – have a great weekend!

Our girls have been very excited about doing experiments lately. To feed this interest, and to motivate me and my husband to keep providing these opportunities on a regular basis, we’ve started having “Sunday Night Science.”

This week’s experiment involved exploring if certain objects will sink or float. This is a simple, but engaging activity that allows young children to practice the important steps in the scientific process: predicting, experimenting, and checking/making conclusions.

We began by collecting items from all over the house. We then sorted them on a large piece of paper according to the girls’ predictions of whether they would sink or float.

Then it was time to experiment! One at a time, each item was dropped into the tub of water with great excitement. The girls decided where the item belonged on the chart.

They loved it when their predictions were correct, but I think they loved it even more when they were surprised by the outcome! Some items that surprised them were the candle, bouncy ball, and index card (they all floated!).

When we were finished, we talked about what we learned. We asked, “What makes something sink?” They answered, “Because it’s heavy,” and “Because it sucks water into it, like the washcloth.” They also decided that the cup and washcloth belonged in the middle of the chart, because they floated at first, then sunk to the bottom as they filled or absorbed water.

The girls thought the index card might act like the washcloth, and eventually sink to the bottom. To test this, we left it in the water while we went about other evening activities. After dinner, it was still floating, so the girls decided it was definitely a floater

Happy experimenting!