One of mine favorite things to carry out are STEM activities and s science experiments! ns love seeing the reaction ~ above a child’s confront when they see scientific research work before their eyes.

You are watching: Why is hot water less dense

A many science experiments take a long time, but not the hot and also cold water thickness experiment!

In this temperature density experiment, youngsters will endure water density, shade mixing, molecule science, and also a entirety lot an ext with simply one experiment that takes much less than 10 minutes to complete.


Try it the end at residence or in the classroom!

Hot and also Cold Water thickness Experiment

If girlfriend love doing fast science experiments that wow, shot this remarkable hot and cold water experiment.

children will ask to execute this one over and also over again!

For much more density science experiments, try making a sugar rainbow, rainbow thickness jar, ocean thickness jar, or a Halloween density jar!

You’ll additionally want to examine out the ultimate list of summer STEM tasks and the ultimate list of summer scientific research experiments. These room super fun ways to include a little bit of STEM finding out to her summer fun!

Why do a hot and also cold water experiment v food coloring


Today, science experiments for youngsters are much more important than ever. Scientific research and modern technology are vast parts of our world today, and also the future will certainly be even much more science and also tech-focused.

Kids who aren’t immersed in the human being of science and STEM expedition from a young age will be left behind your peers, and may battle to find work in the fast-changing landscape of future careers.

Science experiments room usually basic, but they can aid spark a love of science and also discovery in a kid that will certainly follow castle throughout their life.

The basic science experiment the a son does today might spark their desire to find something the will readjust the world in the future.

Every day, young children are using scientific research experiments to resolve real-world problems in medicine and modern technology that have actually never been uncovered before.

And every these scientific discoveries start with a firm structure in science and STEM.

Don’t Miss: 31 creative STEM tasks for Kids



Every science experiment includes four elements:

A Question

Kids should start every science experiment with a question, also if that concern is simply “what will happen?”

A Hypothesis

Before doing any kind of experiment, children should document what they think will happen.

An Experiment

This is where the fun component comes into play. Check the hypothesis to recognize if that answers the question fully.

A Recording and Analysis

As the check is completed, document what happened and also analyze why.

A Re-test

Try different variables and shot a brand-new test to watch if the original answer is confirmed or disproved.

You may additionally like: fast STEM tasks for Kids


Hot water and also cold water experiment explanation


Here is the hot and also cold water density experiment explanation.

The hot and cold water science experiment works due to the fact that of the different density of hot and also cold water.

Certain liquids are less dense than others. If you’ve ever made a thickness jar, it’s straightforward to see this in action.

But… water has the same thickness as other water, right? so why walk it remain separated?

The secret is in the temperature that the water.

The molecules in hot water move faster than those in cold water. Warm water molecule bounce around and also leave gaps. This makes hot water contempt less thick than cold water.

So as soon as you placed the cold water ~ above the bottom, the denser cold water continues to be there.

But as soon as you put the cold water ~ above the top, warm molecules rise. Therefore the colors mix best away.

Because you’re mixing primary colors, they mix into an additional colors as soon as the warm water is top top the bottom.

Hot and also Cold Water scientific research Experiment kit for Kids

This article contains affiliate links. View my disclosure plan for details.

If you’re in a rush, these are our favorite weather science kits.

SPLASH! Water scientific research Kit with 23 Experiments
4M Clean Water Science
Water: Up, Down, and All about (Amazing Science)
The emerging Science the Water: Water scientific research in the XXIst Century
Science4you Water science Kit Experiment
Water (Science Emergent Readers)

What You need to Do The Hot and also Cold Water thickness Science Experiment

12 round Mason Jar through Lid – constant Mouth – 16 oz by Jarden
Spice supreme Assorted Food colors Red Blue environment-friendly Yellow 1.2 Oz
AmazonBasics heat Laminator
Neenah an innovative Collection standards Specialty Cardstock Starter Kit, 8.5 X 11 Inches, 72 count (46407-01)

Mixing Hot and also Cold Water Experiment set Up

Before starting this experiment, you’ll must laminate a little card slightly bigger than the mouth of your mason jar.

Boil a pot of hot water and fill a huge pitcher with ice water.

How to perform the cold and hot water thickness experiment

Fill three jars all the method to the height with ice cream water.

Fill three an ext jars up to the height with warm water (but don’t do it so hot that friend can’t touch the sides of the jar).

Dye one cold jar yellow, one blue, and one red. Repeat because that the warm jars.

First, carry out the experiment v the cold water ~ above the bottom.

Place the index card over the mouth of the warm water jar. Press slightly to make a seal.

Flip the jug over and place the on top of the cold water seasoned (make certain it’s a color combo that will certainly make a secondary color).

Line up the lip that the jars and also carefully traction the card out.

The water will continue to be separated!

Repeat for the other four jars.

Carefully fixed the center of the jars and also flip them. They will certainly mix into secondary colors ideal away!

If girlfriend don’t want the mess threat of flipping the jars, you have the right to simply placed the warm water jar on the top and use the index map over the cold water.

See more: Happy 5Th Of May In Spanish, ¡Feliz Cinco De Mayo! ¡Viva México!

Then, as soon as you relocate the card the end of the way the colors will mix and you won’t have to flip any type of jars.