St. Patrick’s Day Rainbow Experiment, Math Activity, Writing Craftivity & Game

I like to teach about rainbows and the colors of the rainbow around St. Patrick’s Day since part of the lore of the leprechaun is that he sometimes hides his pot of gold at the end of a rainbow.  Here are a few of my favorite rainbow activities.

Rainbow Science Experiment

This simple experiment helps students understand what is needed to form a rainbow and why we don’t always see rainbows even if there is both rain and sunshine.

Materials Needed:

A clear glass or container
Small mirror
Direct sunlight

Fill the glass or container with water.
Place the mirror in the container of water at an angle.
Position the glass so the sunlight is shining directly at the mirror.

rainbow science experiment

Adjust the angle and position of the mirror until you see a rainbow on the wall or ceiling (if you don’t have a white or plain wall, shine it on a sheet of white poster board).

Move the mirror so that the rainbow disappears.  Ask students what you did to make the rainbow no longer visible (moved the mirror).  Explain this is the reason we don’t always see rainbows every time there is sunshine and rain.  The sunshine has to shine through the rain at just the right angle in order for a rainbow to be visible just like the sunshine has to reflect through the water at just the right angle.

Move the glass out of the sunlight and ask students why you can no longer see a rainbow.

I usually let groups of students experiment with the mirror and water on their own to see if they can make the rainbow appear. Afterwards they complete this printable page.

St. Patrick's Day rainbow science experiment printable page

St. Patrick’s Day Rainbow Math Activity

This is a simple, fun math activity that is a student favorite because it involves food and they get to munch any leftovers LOL!  It uses Fruit Loops cereal and reviews math skills and the colors of the rainbow.

Give a pair or small group of students a container or pile of Fruit Loops cereal (make sure there are cereal pieces in all of the colors).

Students make a rainbow using the cereal ensuring the colors are in the correct order (since there is no indigo in Fruit Loops we just do blue then purple/violet).  You can have the students glue on the cereal if you wish to display or keep their rainbows or you can let them build the rainbow and then eat the cereal as a reward after finishing the math portion of the activity.

After making their rainbows, students then count how many cereal pieces of each color they used and answer questions such as:
What color had the most pieces?
What color had the least number of pieces?
How many more red pieces than blue pieces did you use?

counting on a rainbow math activity
St. Patrick's Day Rainbow Counting Math Activity

Since there are now both in classroom and distance learning students, I recently created a digital Google Slides version of this activity so all students could participate even if they did not have the cereal at home.

In the digital version, students look at the instructions on each Google Slide and read how many pieces of cereal to put on each color of the rainbow. Then, they drag and drop the correct amount of colored cereal pieces to each color on the rainbow.

Counting on a Rainbow Digital Activity Answer Key

Rainbow Writing Craftivity – A Rainbow is…

I really like integrating crafts into our curriculum.  They allow students to create unique and personalized pieces that show their creativity and they are also excellent for working on their fine motor skills.

This rainbow writing craftivity relates the colors of the rainbow with students’ environments making the learning more meaningful.

For each color of the rainbow, students write and/or draw something of that color on a rainbow color strip.  They then put the strips in order and glue them to a cloud entitled “A rainbow is…”.  (Since my kinders are familiar with the color word purple more than violet and indigo I use a purple color word strip.  You can replace it with an indigo and a violet color word strip to resemble the real colors of the rainbow.)

rainbow writing craftivity - A rainbow is...

I love how these look hanging from our ceiling!

rainbow writing craftivity - A rainbow is...

Density Rainbow Experiment

In this fun science experiment you use Skittles candy to create a rainbow in a clear glass or jar. It’s perfect to do after Halloween with leftover candy or in the spring around St. Patrick’s Day. It is a simple way to teach students about density.

Materials Needed:

Skittles candy
6 small glasses or jars
eye dropper
hot water
a tablespoon

Place 2 Tablespoons of hot water in each of 5 glasses.

Place the following number of Skittles in each of the 5 glasses:

2 red
4 orange
6 yellow
8 green
10 purple

Skittles for rainbow density experiment
Skittles for rainbow density experiment

Wait for the Skittles to dissolve. If you need to speed up the process, microwave each cup up to 30 seconds.

While the Skittles are dissolving, I have students record how many Skittles of each color we are using for the experiment.

We then discuss which color they think has the most sugar and would therefore be the most dense. I then have students predict what color they feel should be on the bottom of the rainbow (the purple because it is the most dense and therefore the heaviest).

Skittles rainbow experiment page

Once the candy is dissolved, allow the water to cool (cold water is more dense than warm water).

Have students help you arrange the glasses from most dense to least dense.

Using the eye dropper, transfer the purple water to a new glass or jar.

Then add the green water to the new jar using the eye dropper and SLOWLY dribble the water along the inside of the glass. If you dump the water in or add it too quickly they will mix together and the rainbow will not form.

adding colors to the rainbow Skittles density candy experiment

Continue to slowly add the remaining colors in order using the eye dropper to form the Skittles density rainbow.

Skittles density rainbow candy experiment

After the experiment, I have students draw pictures of the rainbow and write what they learned (The water with the most Skittles was the most dense because it had the most sugar. The water layered from most dense to least dense.)

Skittles Rainbow experiment page

St. Patrick’s Day Rainbow Relay Race Game

This is a fun game that gets the students up and moving and practices the colors of the rainbow.  It is played like a relay race so you need a large, open playing area.

Divide students into teams.  Have each team stand in a line on one side of the playing area.

Place a pile of shamrock rainbow color cards (a card for each color of the rainbow) for each team on the opposite side of the playing area.

St. Patrick's Day Rainbow Relay Race Game

On your signal, the first player from each team runs to their pile of shamrock rainbow color cards, picks one up, runs back and tags the next person in line on their team. The next person then runs to the pile, selects a card, runs back and tags the next player.  Play continues until all shamrock rainbow color cards have been picked up.

Once a team has all of their shamrock rainbow color cards, they can place them in a line in the correct order (colors of the rainbow).

St. Patrick's Day Shamrock Rainbow Relay Race Game

The first team to correctly put their shamrock color cards in order is the winner.

If you liked the printables used in these activities and would like to use them in your classroom they are part of my St. Patrick’s Day Bundle which includes a PowerPoint Presentation, science, math, language arts activities, crafts, student gift tags, & a game.

St. Patrick's Day Bundle

You may also like:

A Sneaky Way to Teach Students about St. Patrick’s Day

St. Patrick’s Day CVC Word Riddles

St. Patrick’s Day Treats for Students, Gift Tags & Treat Bag Toppers

St. Patrick’s Day Crafts & Writing Craftivity

National Find a Rainbow Day Activities

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St. Patrick's Day Rainbow Science Experiment, Writing Craftivity, Math Activity, & Game


      1. I just bought that pack, and it doesn’t have the math sheet (fruit loops) in it. Where can I find it? Thank you!

    1. It is just a small make-up mirror I had. Any type of small mirror can be used for the experiment.

  1. Hi Tina! I was wondering if you have the Counting on a Rainbow Froot Loops activity sheets available for purchase outside of the bundle. Thanks so much!

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