### STEP 1

Pour your ingredients into a quart zip-top freezer bag.

• 1/4 cup milk
• 1/4 cup heavy cream
• 1 tablespoon sugar
• 1/4 teaspoon vanilla

Seal the bag and place it into a gallon zip-top freezer bag with 4 cups of ice and 4 tablespoons of salt. Seal that bag.

You will prepare two more batches, one at a time, for a total of three, in the next step.

### STEP 2

Whole Lotta Shakin'

Open Science Journal and create a new experiment, called Ice Cream. Tap the X-axis accelerometer icon, and switch to graph mode.

Set aside your first bag of ingredients and ice and prepare a second.

Now prep your phone to be safe from ice cream accidents while measuring the agitation. We’ll do this by double-bagging it. Put your phone in a quart zip-top bag, squeeze out all the air and seal it. Then put that bag into another quart-sized zip-top bag and seal that as well.

Now place the double-bagged phone, along with the second bag containing the ice and milk mixture, into a gallon bag. (If you want your phone to be even safer, you can double-bag the milk mixture as well.)

Gently shake the bag for 10 minutes. Remove the bag containing your phone, and set the gallon bag with the ingredients and ice aside.

Prepare the third batch of ingredients and ice. Again, place it and the bag containing your phone into a gallon zip-top bag. Shake this bag vigorously for 10 minutes.

Note: If you have a friend to help and a second Android phone with Google’s Science Journal app, you can prepare all three batches at once. Set the first one aside, and then package the second and third with the phones, as you did above. One of you can gently shake the second bag while the other vigorously shakes the third for 10 minutes.

Pour or scoop out the contents of the bags and compare the results.

### STEP 3

Fast and Slow

Compare the two graphs. We can see that the vigorous graph shows far more changes in acceleration and the min and max values are far greater than those on the gentle graph.

### WHAT'S NEXT?

Compare the graphs, and take notes at any point where the graph looks different or interesting to you. Describe the overall shape of one graph versus the other.

How did your shaking affect the overall completeness (how frozen it is) and smoothness of your ice cream? Ice cream is created by freezing the water in your milk. Adding salt to ice keeps the ice from warming up as quickly and keep the temperature bellow freezing longer. Smooth ice cream is created by breaking down the ice crystals as they form to prevent them from creating large hard crystals. Which technique created the smoothest ice cream?

Your safety is your own responsibility, including proper use of equipment and safety gear, and determining whether you have adequate skill and experience. Power tools, electricity, and other resources used for these projects are dangerous, unless used properly and with adequate precautions, including safety gear and adult supervision. Some illustrative photos do not depict safety precautions or equipment, in order to show the project steps more clearly. Use of the instructions and suggestions found in Maker Camp is at your own risk. Maker Media, Inc., disclaims all responsibility for any resulting damage, injury, or expense.

# Plastic Bag Ice Cream

### WHAT WILL YOU MAKE?

If you shake cream and ice long enough, it turns into ice cream. But just how much shaking, and for how long? In this project you will make your own ice cream and record how the amount of shaking affects the final product.

### WHAT WILL YOU NEED?

• Milk
• Heavy cream
• Sugar
• Vanilla
• Ice
• Salt
• Quart zip-top freezer bags
• Gallon zip-top freezer bags
• A smart phone with Google's Science Journal app installed