When dissolved in hot water and allowed to cool, gelatin molecules trap water to create what scientists call a colloid, or a gel. When glycerin is added to a gel, it becomes slippery, so paper won’t stick to it and can be used to make beautiful prints that capture the character and anatomy of a leaf. I’m obsessed with this fun, easy science/art project. Parental supervision is recommended when adding the boiling water to the gelatin.

You’ll need:

1.5 cups vegetable glycerin ( around 375 ml) (I’d recommend ordering this online, since it’s cheaper.

1/2 cup cold water

112 grams powdered plain gelatin (four 1oz boxes of plain Knox gelatine, near Jell-O in the grocery aisle

1 and 1/2 cups boiling water

heat-resistant mixing bowl

kitchen strainer/sieve (optional)

liquid measuring cup

large, flat container, such as a casserole dish or rimmed baking sheet

paper towels

paper

a small paint roller or brayer

liquid acrylic paint

leaves

Directions”

1. Place 1/2 cup cold water in a bowl.
2. Pour half of the glycerin liquid into the water and mix slowly to avoid bubbles.
3. Sprinkle the gelatin powder into the water/glycerin and stir/mash together.
4. Add boiling water and stir carefully, mashing up the lumps until the gelatin dissolves.
5. Put the mixture through the sieve to remove any lumps of undissolved gelatin.
6. Add the remaining glycerin to the strained gelatin mixture.
7. Slowly stir to thoroughly blend all ingredients, being careful not to introduce bubbles.
8. Pour the mixed liquid into the large, flat container.
9. Use a paper towel to skim any bubbles off the surface of your gelatin mix
10. Let the gelatin sit undisturbed for an hour or two, and then put it in the refrigerator for 2 hours.
11. While the plate solidifies, find some fresh leaves. Use a book or app to try to identify the leaves you picked.
12. When the gelatin plate is ready, you can leave it in the container or remove it. (I left it in the casserole dish.) Use the roller to apply paint to the gelatin
13. Lay some leaves on the paint and use a finger to smooth each part of the leaf down into the paint. To highlight the veins on the leaf, lightly roll paint over the leaf.
14. Carefully put a piece of paper down on top of the leaves and paint. Use your fingers to smooth the top sheet of paper and transfer the paint. Lift the paper to reveal the leaf prints.
15. Peel the leaves off the painted gel and place them between two sheets of paper to make a positive print. Smooth the paper to transfer the paint and separate the paper to see the images.
16. The gelatin plate can be reused with different paint colors. Just wash the gel plate with a wet paper towel between uses, and store it between pieces of saran wrap. It should keep for a few weeks.

Snow, ice, wrapping paper and free time are abundant over the holidays.  Here are a few fun experiments to fill the hours between celebrations. Click on the experiment name for directions.

Holiday Window Gellies: Kids of all ages love making these from gelatin and food coloring!

Snow Science: Melt snow to see how much water and dirt it contains.

Magic Ice Experiment: Lift an ice cube from a glass of water using only a string and some salt.

Wrapping Paper Egg Drop: Have a contest to see who can engineer the best egg-protecting container from left-over boxes, wrappers and decorations.

Rock Candy: Grow your own sugar crystals on a stick. What happens if you add a little peppermint oil?

What happens when food coloring molecules move, or DIFFUSE through gelatin, the substance that makes jello jiggle?

This creative science experiment that my kids and I invented lets you play with floatation physics by sprinkling glitter on melted gelatin, watch colorful dyes diffuse to create patterns and then use cookie cutters to punch out sticky window decorations.  Water will evaporate from the gelatin, leaving you with paper-thin “stained glass” shapes.

You can watch us making them on Kare11 Sunrise News by clicking here.

You’ll need

-plain, unflavored gelatin from the grocery store or Target

-food coloring

–a drinking straw

-water

-a ruler

-glitter

*You can use the recipe below for two pans around 8×12 inches, or use large, rimmed cookie sheets for your gelatin. For a single pan, cut the recipe in half.

Step 1. Add 6 packs of plain, unflavored gelatin (1 oz or 28 gm) to 4 cups of boiling water. Stir well until all the gelatin has dissolved and remove bubbles with a spoon.

Step 2. Allow gelatin to cool to a kid-safe temperature. Pour the liquid gelatin into two large pans so it’s around 1-1.5 cm deep. It doesn’t have to be exact.

Step 3. Sprinkle glitter on the gelatin in one pan.  What happens?

Step 4. Allow the gelatin to harden in both pans.

Step 5. In the pan with no glitter, use a straw to create holes in the gelatin, a few cm apart, scattered across the surface. It works best to poke a straw straight into the gelatin, but not all the way to the bottom. Spin the straw and remove it. Then, use a toothpick or skewer to pull out the gelatin plug you’ve created. This will leave a perfect hole for the food coloring. Very young children may need help.

Step 6. Add a drop of food coloring to each hole in the gelatin.

Step 7. Let the gelatin pans sit for 24 hours. Every so often, use a ruler to measure the circle of food coloring molecules as they diffuse (move) into the gelatin around them (read about diffusion at the bottom of this post.)  How many cm per hour is the color diffusing?  Do some colors diffuse faster than others? If you put one pan in the refrigerator and an identical one at room temperature, does the food coloring diffuse at the same rate?

Step 8. When the food coloring has made colorful circles in the gelatin, use cookie cutters to cut shapes from both pans of gelatin (glitter and food coloring), carefully remove them from the pan with a spatula or your fingers, and use them to decorate a window. (Ask a parent first, since some glitter may find its way to the floor!) Don’t get frustrated if they break, since you can stick them back together on the window.

Step 9. Observe your window jellies each day to see what happens when the water evaporates from the gelatin.
When they’re dry, peel them off the window. Are they thinner than when you started? Why? Can you re-hydrate them by soaking the dried shapes in water?
The Science Behind the Fun:

Imagine half a box filled with red balls and the other half filled with yellow ones.  If you set the box on something that vibrates, the balls will move around randomly, until the red and yellow balls are evenly mixed up.

Scientists call this process, when molecules move from areas of high concentration, where there are lots of other similar molecules, to areas of low concentration, where there are fewer similar molecules DIFFUSION. When the molecules are evenly spread throughout the space, it is called EQUILIBRIUM. 

Lots of things can affect how fast molecules diffuse, including temperature.  When molecules are heated up, they vibrate faster and move around faster, which helps them reach equilibrium more quickly than they would if it were cold. Diffusion takes place in gases like air, liquids like water, and even solids (semiconductors for computers are made by diffusing elements into one another.)

Think about the way pollutants move from one place to another through air, water and even soil. Or consider how bacteria are able to take up the substances they need to thrive. Your body has to transfer oxygen, carbon dioxide and water by processes involving diffusion as well.

Why does glitter float on gelatin? An object’s density and it’s shape help determine its buoyancy, or whether it will float or sink. Density is an object’s mass (loosely defined as its weight) divided by its volume (how much space it takes up.) A famous scientist named Archimedes discovered that any floating object displaces its own weight of fluid. Boats have to be designed in shapes that will displace, or push, at least as much water as they weigh in order to float.

For example, a 100 pound block of metal won’t move much water out of the way, and sinks fast since it’s denser than water. However , a 100 pound block of metal reshaped into a boat pushes more water out of the way and will float if you design it well!

What is the shape of your glitter? Does it float or sink in the gelatin?

Here’s a video I made for KidScience app that demonstrates how to make window gellies

Credit: My 11 YO daughter came up with the brilliant idea to stick this experiment on windows. I was just going to dry out the gelatin shapes to make ornaments. Kids are often way more creative than adults!