SINK OR FLOAT
Children LOVE to play with items in water.
Fill a small tub with water
Gather a few materials from around your house like a paper clips, pennies, spongs, crayons, plastic straws, wooden blocks, etc.
Have your children guess: 1- Which objects do they think will float in water and which will sink? 2- Will the bigger objects sink and the smaller objects float?
Place the objects in/on the water and find out the answer.
Explain to your children that it seems logical that bigger objects should sink while smaller objects should float. But the density of an object determines whether an object will float or sink.
Talk about the force of gravity when they drop items into the water
For further learning, continue with this experiment:
Saltwater Density Experiment
Add increased amounts of salt to the water in the tub.
Mix well to dissolve the salt. Salt changes the density of water. That makes the water denser which means it adds more weight to the water. Thus, objects that are denser than water sink and those that are less dense than water float. So, saltwater allows more objects to float on the surface that would sink in fresh water.
Small plastic items will work best with the change in density of the water.
Safety: Remind your children to wash their hands after they are finished with the activity.
Questions to ask your children:
Do you float better in salt water?
Do various objects float better in salt water?
What might be causing one object to float or sink? What determines if an object will sink or float?
Do you think freshwater and saltwater have the same or different densities?
If the density of an object is less than the density of saltwater, what will happen?
Why do some objects sink in freshwater and float in saltwater?
OCEAN TWIRL
Have your children fill a plastic bottle about half full with water.
Add a few drops of blue food coloring to it and shake it well.
Fill the rest of the bottle with mineral oil.
Add sequin fish shapes and plastic sea animals to the bottle.
Secure the top with masking tape/ packing tape. Hold the bottle sideways and gently tip it to create waves.