Milk & Cookies and the Scientific Method

Teaching students about the processes scientists use is a key step in building a science foundation at the beginning of the year. In this post I’ll share a fun and simple science experiment for students to explore buoyancy as they learn the steps of the scientific method.

Milk and cookies are every kid’s favorite so why not use them to teach science? I thought milk and cookies were the perfect materials for our first science experiment and of course, we could eat the leftovers!

Exploring Buoyancy to Teach the Scientific Method

While most students are familiar with the phrase sink or float, they may not know the term buoyancy. This experiment enables students to explore why some things sink and other things float as they make observations and conduct an experiment.

To introduce the concept of buoyancy I like to start with a mini lesson and explain additional science vocabulary. Terms such as molecules, density, and buoyant. I also ask questions. “Why do you think some things float, while others sink?” and “How can can something as heavy as a cargo ship float across the ocean without sinking?”.

I presented the questions, “Are cookies buoyant?” and “Will they sink or float in milk?”. Walking through the steps of the scientific method, I recorded questions and guided students with actionable steps they would take to find out.

The Great Cookie Dunk Experiment

After placing students in groups of 4 each received 4 different cookies and 4 cups of milk. We used mini cookies that I found at Walmart and the dollar store.

Before starting their science experiment, students observed the properties of each cookie and recorded those on their paper. Next, they predicted whether the cookie would sink or float.

As students conducted their experiments the results were not always what they expected. Some cookies sank right away while others took a while. Students observed which cookies absorbed milk quickly and which did not.

Students draw their results and discuss why they think each cookie either sunk or floated. Some of the things to have students consider are: the weight of the cookie, whether air pockets are visible, “Does it have 1 or 2 cookies with filling in the middle?, and do chocolate chips make the cookie sink because of their weight or float because of the oil and fat they contain?

This simple milk and cookies buoyancy experiment is a lot of fun for kids and a great activity for teaching the scientific method.

Where can I get the lab worksheets you used?

The PowerPoint lesson and student pages shown in this post are available in a complete science unit, Scientists & The Scientific Method.

The unit includes 10 science lessons, and a teaching Power Point and science experiments to introduce your students to scientists, types of science, science tools and safety, and the scientific method. Three science experiments, student journal activities, posters and anchor charts give you everything you need to start the year off right as you lay the foundation for future science lessons.