Compiled by: Meghan Burnham
Rivers2Lake Education Intern
Saltwater vs. Freshwater Experiments
Standards (NGSS)
K-LS1-1. Use observations to describe patterns of what plants and animals (including humans) need to survive.
K-ESS3-1. Use a model to represent the relationship between the needs of different plants or animals (including
humans) and the places they live.
2-PS1-1. Plan and conduct an investigation to describe and classify different kinds of materials by their observable
properties.
2-PS1-1. Plan and conduct an investigation to describe and classify different kinds of materials by their observable
properties.
3-LS4-3. Construct an argument with evidence that in a particular habitat some organisms can survive well, some
survive less well, and some cannot survive at all.
3-LS4-4. Make a claim about the merit of a solution to a problem caused when the environment changes and the
types of plants and animals that live there may change.
Compiled by: Meghan Burnham
Rivers2Lake Education Intern
Discuss the different types of water.
Can you name bodies of water? Where are they found? Do you know if they are salt water or
freshwater? How do you know? What is Lake Superior? Which animals NEED salt to survive,
the ones in fresh or salt water? What would happen if the animals were put in saltwater that were
freshwater animals and vice versa.
Let’s look at a map: What bodies of water do you see? What kind of water are they? Do you
think there is more saltwater or freshwater?
Let’s look at some differences between the two1. Fill bowls with water and add salt to one of the bowls.
2. Have students “taste” the water with popsicle sticks. What was it like?
3. Have two identical objects, i.e. an egg, and ask what the students think will happen when
you place an egg in freshwater and an egg in saltwater. Will they sink or float? Will they
do the same in the different types of water?
4. Place the eggs in the water and then discuss if they hypothesized correctly and discuss
why the eggs did what they did.
Explanation: Things float in salt water because saltwater is denser than freshwater.
Other ways to prove hypothesis: Salt water with food coloring in it will sink because it is denser
than freshwater.
Regular pop will sink because it has more sugar and is denser. Diet pop will float because it is
less dense with less sugar.
Another question: What will happen when you completely boil off the water in saltwater and
freshwater? Do you have any predictions? Does salt water leave salt behind? Will freshwater
leave salt behind?
1. Mix the two pans of water and begin to boil.
2. Explain that you would let it boil all the way but because of time you did it ahead of time.
3. Show them what the two types of water left behind.
4. Discuss what happened.