Scientific Objective: Exploring Density
Materials Needed:
Modeling clay (not play dough, not earth clay)
Small tubs (enough for every pair of children)
Bear counters
Access to water
Slice of bread
Towels
Set Up:
Before the experiment, fill the tubs of water (about halfway).
Procedure:
Give each child a ball of clay and ask them what they think will happen if you drop it into the water. Have children drop a ball of clay into the water to see if it will float or sink (it will sink). Next, ask them to form a boat with the ball of clay. What will happen to their boat if they put it in the water? Will it float or sink? Have each child try it. Most of the boats will sink. Ask the children to take the boat out of the water and keep trying to form it in different ways until they make a boat that floats. Tell children they need to press the clay flatter to give their boat less density so that it will float. Once they have a boat that floats, have them try putting animal counters in the boat one by one, to see how many the boat will hold without sinking. You can also try making boats with aluminum foil.
Note: I have done this activity inside the classroom, and it worked out fine as long as we had plenty of towels available. However, I prefer doing this activity outside.
Extension:
Reinforce this concept by placing a slice of bread on top of the water. It will float. Then take the bread and wad it up into a ball. Place it in the water again. It sinks.
Find more Transportation Activities for Pre-K on the category page.
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I did this activity with my kids yesterday. They loved it. I used aluminum foil, jewels,and teddy bears. They really enjoyed seeing how many items they could float on their boat before it sank. Thank you for the fun suggestion.
this is a fabulous site. I love the ideas!!!
I really like Karen’s activities because they allow children to use scientific skills like predicting, testing and re-testing, analyzing, and most of all, thinking. I also like that she uses water often because young children enjoy water play. A good inquiry-based teacher can use probing questions with any of these activities would scaffold the scientific principles being taught using scientific words in context and eliciting vocabulary to describe their experience. Using these activities with young children will help them develop concrete scientific concepts.
I LOVE this idea and will try it – but I am an engineer and my hair bristled reading the explanation about density (‘make the clay more dense so it will float’)…
It’s actually the opposite – by flattening and hollowing out the clay you’re allowing a less dense item to displace the same amount of water. When the density of the water displaced is higher than the density of the item displacing the water, the item will float!
The bread is a perfect example. When you wad up the bread, you take out the air bubbles and make it more dense. More dense than the water it displaces, so it sinks!
Thank you for adding this explanation. I want to do this with older students and was trying to figure out an explanation of “why”.
I’m a former chemistry teacher and thought the same thing about the density explanation. Emily, your explanation is great and I recommend, Amy, that you change the wording of the explanation to be that they need to flatten the clay out to make it less dense than the water so it will float.