Science play is a new area of play for our family. Maybe other parents are more on the ball and have been doing science experiments with their kids since birth. Maybe some science-minded parent brings his baby home from the hospital and the next day starts showing her bugs in a jar.
We have not thought about it much until the last year or so. Our 5-year-old son, however, has recently become very interested in how things work—computers, space travel, the weather, you name it—so we’ve been incorporating more science play at home. Recently he asked why some things float and others sink, so after a quick explanation of density and buoyancy, I came up with this Easter-themed activity.
What You’ll Need:
- Several plastic Easter eggs
- Scotch tape
- Small items to place inside: quarter, cotton balls, MicroMachines, dry beans, jelly beans, rocks, marbles
- A large bowl of water
Experiment #1: Will it sink or float?
This is a classic kids’ experiment with a fun Easter twist! You’ll need to start by putting a small piece of tape over the holes on all the plastic eggs (to keep water from getting inside).
Create a chart with a list of each item on the side (beans, marbles, cotton balls), and two columns at the top: “Sink?” and “Float?” Have your child make a hypothesis about which items will cause the egg to sink and which ones will not. Then test out their hypotheses to see if they’re right!
Experiment #2: How many coins does it take?
This is a similar experiment to the one above, but instead of putting just one object inside, add quarters one at a time to the egg until the egg sinks. Have your child predict how many it takes. As they add quarters, they’ll see the egg sink lower and lower in the water, until finally it drops to the bottom of the bowl.
Explaining Why Things Float and Sink
You can explain to your child that the empty egg floats because the plastic and the air inside are less dense than the water. Any easy way to show the difference is to fill up one of the plastic eggs completely with water and have your child feel how heavy it is. In order to sink, another egg must be heavier than the water that would take up the same amount of space—so that’s why the water-filled egg is a good comparison and easy way to understand this subject.
Variation for Older Kids
Using a kitchen scale, have kids weigh the water-filled egg and then eggs filled with other objects. Using this information, ask them to make a more “educated” prediction about which eggs will float and which will sink.