This sink or float activity has kindergarten and 1st grade scientists predict and sort 12 picture cards on a Float and Sink mat, then circle new floating objects. Answer key included.
This Sink Float Examples Worksheet has 3rd graders sort eight everyday objects into Sinks and Floats columns, then name the object in four sentences. Answer key included for hands-on science practice.
Splash! Predict, test, and find out
Sink or float is often a child's very first science experiment. Kids learn to make a prediction, test it in water, and record what happens. Younger children discover that size doesn't decide it: a big log floats while a tiny pebble sinks. Older students learn it depends on how heavy something is for its size (its density) compared to water, and that shape matters too, which is why a ball of clay sinks but a clay boat can float. The click moment is when a child predicts a big apple will sink, drops it in, and gasps when it bobs up.
All you need is a tub of water and curious kids. These moves turn splashing into real science.
Before anything goes in the water, kids sort objects into "I think it will sink" and "I think it will float." Then test one at a time and move each to where it really belongs. The surprises are the best teaching moments.
Why it works: going from real objects to pictures to symbols is a core recommendation of the U.S. Department of Education's elementary math guide.
Try it withSink or Float ActivityActivitiesOpen it →Kids draw each object either at the bottom of the tub or on top of the water. Pictures give younger kids a way to record results before they can write, and they make patterns easy to see.
Why it works: children learn more from words and pictures together than from words alone (Mayer, 2009).
Try it withSink Float Examples WorksheetWorksheetsOpen it →Drop a ball of clay in the water so it sinks. Then challenge kids to reshape the same clay so it floats. When a flat boat finally bobs on top, they discover that shape matters, not just weight.
Why it works: handing over the work step by step, from teacher to student, is one of the most widely used teaching frameworks (Pearson and Gallagher, 1983).
Teacher favorites right now: Sink or Float Activity and Sink Float Examples Worksheet.
It depends on density: how heavy something is for its size compared to water. Things that are less dense than water float, and things that are more dense sink. Shape matters too, because spreading out lets an object push aside more water.
It works from preschool through elementary school. Little ones predict and test, while older kids measure, record data and explain density and buoyancy.
Try a mix of surprising items: an apple, a coin, a cork, a crayon, a rock, a sponge, a plastic spoon and a leaf. Include some big things that float and small things that sink.
The peel is full of tiny air pockets that help the orange float. Without the peel, the orange is denser than water and sinks.
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