What is the Sesame Street sink or float activity?

It's a simple preschool science experiment where kids predict and test whether everyday objects sink or float in water. The Sesame Street version ties the guessing game to characters like Elmo or Cookie Monster to keep little ones engaged.

What objects should I use for a sink or float activity?

Use safe, waterproof items like rubber ducks, plastic blocks, corks, spoons, coins, and small toys. Include a mix so some sink and some float, and let kids test each one.

How do I set up a sink or float station for preschoolers?

Fill a clear bin or tub with water, place it on a low table with towels nearby, and arrange objects in a basket. Add a simple chart with sink and float columns so kids can sort items after testing.

What can preschoolers learn from sink or float experiments?

They practice making predictions, observing results, and comparing outcomes, which builds early science and critical thinking skills. It also introduces basic ideas about weight, size, and materials.

Is the sink or float activity safe for toddlers and preschoolers?

Yes, with supervision—always stay within arm's reach and empty the tub right after play. Choose large objects that aren't choking hazards and avoid anything that could break or rust.

Sesame Street Sink or Float Science Activity for

The Sesame Street in Communities “Sink or Float” activity gives preschoolers a simple way to test what happens when objects go into water. A child predicts whether an object will sink or float, drops it into a container, then compares the result with the guess. The main lesson is how to make and check a prediction. You need a clear container, water, a towel, and a few objects that can get wet.

What children practice

Preschoolers can explore science without learning formulas. In this activity, they observe an object, make a prediction, test it, and describe what happened. The NAEYC describes hands-on investigation and adult-guided conversation as ways young children learn science.

The Head Start early learning framework also includes observation and prediction in its guidance on preschool science. Keep the conversation tied to what the child can see: “It went to the bottom” or “It stayed on top.”

A guess does not need to be correct to be useful. If a child predicts that an object will float and it sinks, the result gives them something to compare with their idea. Let the object’s movement answer the question before you explain anything.

What you need

Gather:

A clear, stable container, such as a plastic tub or deep bowl
Water
A towel
A few small, water-safe objects

A clear container makes it easier to see an object move through the water and settle at the bottom. Choose objects that are large enough not to be a choking hazard and that you are comfortable getting wet. Avoid breakable items, objects with sharp edges, and anything that could leak or dissolve.

The Sesame Street in Communities activity page offers the sink-or-float activity. Keep the selection small enough that a child has time to make a guess and notice the result for each object. For example, you might choose a cork, a coin, a plastic spoon, and a small rock.

Set the container on a stable surface where the child can reach it without climbing or leaning over an edge. Use only enough water for the objects to move freely. Stay within arm’s reach and supervise throughout. Young children need close attention around water, even in a shallow container.

How to run the activity

Start with one object. Let the child hold or look at it, then ask, “What do you think will happen when it goes in the water?” Accept the answer without correcting it.

Invite the child to place the object in the water. Watch together. Describe what happened in plain words: “It sank to the bottom” or “It stayed on the surface.” Then ask, “Was that what you expected?”

Continue with another object and follow the same routine. Give the child time to answer and look closely before moving on. Stop when interest fades. The activity can be brief; there is no need to finish every object you gathered.

Keep the focus on the child’s observations. If they want to handle the object again or make another prediction, let them, as long as the objects and water remain safe. If they begin splashing or dropping items without looking at the result, you can end the science activity and move on to something else.

One example: testing two spoons

Hold up a metal spoon and ask the child to predict what will happen. The child says, “It will float.” Let them place the spoon in the water. If it sinks, describe the result: “You thought it would float, and it went to the bottom.”

Next, show a plastic spoon and ask for another guess. It may float or sink depending on its shape and construction, so let the child find out instead of promising a particular result. Ask what they noticed and how the outcome compares with the metal spoon.

This example lets the child make a prediction, test it, and compare two results. You do not need to label a guess as right or wrong. The observation is enough to start a conversation: “What do you think made the spoons act differently?”

Keep the conversation simple

Use concrete descriptions before offering explanations. For example:

“The coin went to the bottom.”
“The cork is staying on top.”
“You guessed sink. What happened?”

If the child asks why, you can say, “Objects behave differently in water. What do you notice about this one?” There is no need to give a full explanation of buoyancy. The goal is to help the child notice and talk about what happened.

A child may give the same prediction for every object or change their mind after seeing a result. Either response gives you a chance to ask what they expect next. Avoid turning the activity into a quiz. There is no score, and children can revise their ideas as they observe more objects.

When the activity is finished, you can place the objects in two groups: those that sank and those that floated. Invite the child to help sort them and describe the groups. If an object’s result is hard to see, test it again together.

Key Takeaways

The Sesame Street sink-or-float activity uses a simple routine: predict, test, and compare.
Use a clear, stable container, a small amount of water, and objects that are safe to handle.
Ask for a prediction before each test, then describe what the child observes.
Let the child’s observations guide the conversation. A prediction does not need to be correct.
Supervise closely around water, and stop when the child loses interest.

How to Run a Sesame Street Sink or Float Science Activity for Preschoolers