Marshmallow Marvels

CA Standards--Third Grade

• Measurement using metric and English units--Foss--Measuring Matter Module

• Add, multiply, subtract, divide using volumes

• Basic Multiplication and Division

Materials

A modified Rice Krispy Squares recipe is used. Pre-measure out the ingredients if time will be a concern.

• Measuring cups and spoons with both metric and English units.

• Graduated cylinder

• Yard stick

• Non-stick cooking spray, 8x8 baking pan, parchment paper, large saucepan, stove, spatula

Ingredients: Butter, marshmallows, salt, oat cereal like Cheerios, dried cranberries, white chocolate chips

Procedures

1. Show students a measuring cup with metric and English measures.

2. Introduce the idea that measurement is useful because people need consistency so it’s the same from place to place and something that everyone can agree on.

3. Remind them about previous week where size of instructor’s hand and student’s hands were different and how standardized measures help make a far better building. Go over some of the old measurement terms and some history.

4. Earliest measurements were based on length.

   • Foot (1 human foot), eventually standardized to some king’s foot

   • Hand (across the palm, still used in horses)= 4”

   • Span (tip of thumb to tip of little finger when fingers are spread)

   • Cubit (length of forearm from point of elbow to tip of middle finger)

   • Yard (now 3 feet but was distance from tip of nose to end of thumb when arm outstretched).

   • Fathom (finger tip to finger tip when arms are spread)

5. The metric system was created by a group of French scientist. Everything is done by multiplying and dividing by tens.

   • Length is the meter, eventually get the kilometer which is 100 times more or the centimeter (how many cents in a dollar?) which is 100 times smaller.

   • Liquid measure is tied to the meter, too. The liter is the standard and you arrive at that by thinking that 1 liter equals a cube 10 cm x 10 cm or 1000 cc or cm³ which equals 1 kilogram. So 1 cubic centimeter =1 milliliter = 1 gram.

   • So, dry weight measurement (like cups in the English system like when you measure flour) is also equal to the meter.

6. Complete the worksheet using the chart, comparing to the measuring cup/spoons with English and Metric measurements when possible.

7. Prepare the recipe. Kids can work on the Science extension to measure how much 2 dried cranberries weigh using the graduated cylinder and water displacement while you are working on the recipe.