Styrofoam
Because some objects are a lot denser than water so the sink and others are less denser so they float
No, some sink.
It's far from clear what the actual question is. Some objects float in both salt and fresh water, some objects float in neither, and some objects float in one but not the other. Any object that floats in fresh water will float in salt water, but the reverse is not true.
The types of objects that will float on water are foil, most rubber, and some plastic.
It is to do with to volume and mass.
Some objects that float on milk are coins, cork, small plastic toys, and seeds like sesame seeds or chia seeds.
Objects such as rubber ducks, pool toys, and foam noodles are likely to float in water. In the kitchen, some plastic containers and utensils may float as well. Additionally, some bath toys and small plastic items can float in a bathtub.
because some objects are much denser(heavier) than water so they sink
Because some objects are heaver than others.
Objects that are less dense than water can float in it. Some examples include wood, plastic, cork, and certain types of metals like aluminum. Additionally, objects that are hollow or have air pockets can also float in water.
Some objects that do not float on water include rocks, metals such as iron and lead, and most types of glass. These items are denser than water, causing them to sink when placed in water.
Because of the objects density.