Sink and Float – Packet #2 Primary

Sink and Float is a favorite in every 3 to 6 Montessori classroom. So easy to recreate at home!


Goal:To hypothesize & determine which items will float and which will sink

–A large clear container (storage containers with lids work great)
–A pitcher of water
–Small objects of varying weight & density (endless possibilities: marble,wood, paperclip, feather, penny, tealight, eraser, plastic fork, metal fork, tissue paper, cardstock, pencil)
–Two labels- 1. Sink 2. Float
–A towel for drying

1.Have the work available with all of the objects and labels inside the container. Towel beside.
2. Ask your child to set the work up. See photo on left.
3. Have a blast working with your young scientist as you share hypotheses & test them out!
5. Make sure you show your pre-reader that the label beginning with “sssssss” is “Sink”.
6. Vocabulary: sink, float, heavy, light, surface, bottom, buoyant, dense, density, displacement, surface area, surface tension, hypothesis, accurate..when you use scientific terms without making a big deal out of it, your child will learn them easily.
7. Have your young scientist dry all the objects and the container with the towel!

The first rule of Sink and Float is : DRY, DRY, DRY! The scientist should dry everything before putting this work on the shelf for later use. No one wants a moldy science shelf!

Make sure the bowl or container is deep enough so the difference and space between sinking and floating is obvious

Challenges: try adding something to the water like dish soap and see if that alters results. Experiment in the bathtub with larger objects.

Print the labels below & the scientist can cut them out. Wrap in clear packing tape for a DIY lamination and they will resist water!