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The Ultimate Harry Potter Science Activities for Halloween or Birthday Parties Part 2

By Blog Editor Susan Wells

Last Friday, I shared my 7-year-old daughter’s Ultimate Harry Potter party and how we created some unique and creative decorations out of science supplies. This was a birthday party, but it can easily be tweaked for a Halloween Harry Potter party or plain old Mad Scientist party.

For the party, I set up different classes and activities to go along with the lessons and teachers in the series. As the kids arrived, I sorted them into houses, by having each one sit on a stool under our Sorting Hat poster. When they sat on the stool, they reached into a bag and picked a ring with a house crest. Several websites sell Sorting Hats or share ideas on how to make your own. This wasn’t a huge focus in our party, so I went with the printable.

After all of the kids were sorted into Gryffindor, Slytherin, Hufflepuff and Ravenclaw houses, they sat down at the tables in the Great Hall, ready for their first lesson.


The first Hogwarts class was Magic. I set it up so that each class had at least two lessons – one as a demonstration and the other as hands-on. The hands-on lessons had take homes for the kids. I built their goodie bag throughout the party.

For Magic, I began with the Magic Coloring Book. I have had my coloring book for a long time and unfortunately it is no longer available. The book helps the kids magically draw, then color pictures as you flip through the pages.

Next, I did the three-cup Monty using Water Gel. Water Gel is a polymer powder that is similar to what is found in a baby’s diaper. The polymer absorbs water. To do this demonstration, ask for a volunteer. Start with three solid cups. Fill one 1/2 way with water. Ask your volunteer to tell you which cup holds the water. Set the cup with the water down with the two empty cups. Mix up the cups and then ask your volunteer to point out the water cup. When they identify it correctly, pick up the cup and pour the water into the next cup and mix the cups again. Ask your volunteer to find the water. When they again identify the correct cup, pour the water into the 3rd cup and mix up the cups again. This time when your volunteer points at the cup full of water, try to pour the water into the 1st cup again. The water doesn’t pour, and your volunteer and audience will be confused. What happened to the water? The 3rd cup contained a scoop of Water Gel powder in the bottom. When the water was poured into the cup, the powder absorbed the water and became solid.

My final lesson was mixing a liquid and making it siphon itself out of the cup. I used Gravigoo for this activity. Gravigoo is another polymer that when mixed with water will make water appear to flow uphill. I let the kids play with the Water Gel and Gravigoo and take a little home in a bag when we were done.


For this class, we held a scavenger hunt. At the craft store, I found rubber spiders, bugs, snakes, rats and frogs. The kids were sorted back into their Hogwarts houses for teams and given a type of animal family (frogs, spiders, snakes, etc) to find. The first group back with all of their creepy crawly creatures won a small prize. This was perfect, because it got the kids up and running around before coming back to sit down for our next class.



As Professor Trelawny, this was my favorite subject. For this class, we turned off the lights and glowed in the dark as we tried to see into the future. First, I made my own large Crystal Ball and told my class what I saw. I saw them becoming true wizards and witches after the party. To make this amazing Crystal Ball with dry ice and a little soap, visit SteveSpanglerScience.com for complete instructions.

I then gave each child yet another polymer…a large Jelly Marble. They could look into their crystal ball and tell me the future. The kids took turns sharing what they saw in their crystal ball. This was so fun and gave each child a time to shine. The giant Jelly Marbles are no longer available, unfortunately, but you can get creative by using smaller Jelly Marbles, water balls, touchable Boo Bubbles, clear marbles, Polymer Cubes (for a twist on the round crystal ball), etc.

To wrap it all up, the kids made Future Telling Wands. I gave each child a Baby Soda Bottle Test Tube. I also had the racks that come with the test tubes to keep everything stable while the kids made their wands. The kids had the choice of making a bubbling lava lamp where we filled the test tube 3/4 full with water and then filled the last 1/4 with vegetable oil. Drop a few drops of food coloring (which can stain) or Color Fizzer Tablets (do not stain). I also added a few drops of Pearl Swirl to make the liquid bubble, swish and swirl inside the wand. For complete instructions and other cool ideas for wands and activities using Baby Soda Bottle Test Tubes, visit our experiments website.


For Charms class, we made Firefly test tubes. The night before I hydrated a large bowl of Water Jelly Crystals. The crystals are polymers that grow in water. After they were hydrated, I put the Jelly Crystals in a plastic bag with Glow Powder. The powder coats the crystals a lot like shake and bake. The Glow Powder glows in the dark. During the party, the kids took handfuls of Glow Powder covered Jelly Crystals and filled their wands. When the lights went off, they had firefly wands to light up the night sky or the Forbidden Forest.


Potions was the perfect party ender and prepped the kids for cake and treats. I began by mixing my own Professor Snape potion, the Purple Paradox. This potion starts as a clear liquid and turns purple before your eyes. Wait a few moments and the potion will turn back to clear. This magic potion is perfect to ward off Death Eaters, but is not for drinking.

After following my careful instructions, my students mixed their own potions. We had different colored sodas available, from Sprite to Orange to Sun Drop. Light-colored sodas work the best. Drop in a tablet or two of Instant Flavor Drink Tablets and watch the color change. The flavor changes too! These drink tablets don’t taste fabulous in plain old water, but mix them into soda and POOF! you have your own potion. Now, dare your friends to drink it.

The kids had a blast making up their own potions and trying them out. They bubbled and changed colors before their eyes. No drink was the same.
Here are some additional activities you can incorporate into your Halloween, Harry Potter or Mad Scientist Party:


New from Steve Spangler Science:

If you are throwing a Halloween party, classroom party, Harry Potter or Mad Scientist party, you MUST include these amazing new products. Brand new this week. It’s too late for my party, but not for yours. This product line is exclusive and only available only from Steve Spangler Science. Steve Spangler himself worked to create the perfect mixture.


Slime Factory
Get ready to line them up and run them through the slime factory. Giant pump filled with slime goo comes with mix-ins like Jelly Crystals, styrofoam beads, plastic bugs, glitter and more. Make your own slime potion and take it home in a shaker cup.

Vampire Slime and Vampire Veins
Green goo that turns red in the light. Spooky, cool and extra awesome. Kids will go crazy for these in potion jars or as an activity.


Heat Sensitive Color-Changing Insta-Worms
These worms change color depending on the temperature. Place them in the freezer or ice water or hot water and watch the color go from white to pink or blue.

For more decorating and activity ideas, here is a fun blog post from Alison’s Wonder Scraporium that has some great ideas and printables. I used her Hogwarts Express ticket invitations. So cute and I received a lot of complements.

Activity Village also has a lot of great printables and activity ideas for a Harry Potter party or in the classroom.

Mrs. Happy Homemaker has a fun way to make magic potions using ice cubes and Kool-Aid.


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