### If You Have...An Apple

Use It to Demonstrate: Rate of decay

What to Do: Peel and slice an apple. Fill a baggie halfway with water. Place one slice in the baggie and seal. Place the baggie outside in the cold to freeze. Let another slice of apple sit at room temperature. Wait a few days and then let students compare the rate of decay of each slice.

### If You Have...Pennies

Use Them to Demonstrate: What causes ice to melt

What to Do: Place each penny in a Styrofoam cup filled a quarter of the way with water. (Make sure the pennies are not close to the cups' edges.) Freeze until solid. Peel the cups off so you have a small block of ice. Give each student a block of ice and have them place it on a plastic plate. The pennies should be at the bottom. Challenge students to see who can melt the ice and get to the penny the fastest without breaking the ice or picking it up with their hands.

### If You Have...Hairspray

Use It to Demonstrate: How snowflakes are unique crystals

What to Do: A few days before a snowy day, chill pieces of smooth glass (microscope slides work great) and aerosol hairspray or artists' fixative in the freezer or outdoors. (Note: These items need to be chilled so they don't melt the snowflakes.) When you're ready to catch snowflakes, spray one side of the glass with the hairspray or fixative. Have students hold out the glass, sticky side up, to collect falling snowflakes. Next, place the glass in a chilly area where it won't be disturbed for several hours. Once the snowflake imprint is dry, it doesn't need to be kept cold. For added fun, examine the snowflake imprints under a microscope.

### If You Have...Bubbles

Use Them to Demonstrate: How ice crystals form, water's freezing point

What to Do: On a day that's 32 degrees or below, take the students outside to blow bubbles. Have them catch a bubble on their wands and observe as the bubble freezes. Encourage them to touch it, blow on it, or let it fall to the ground. Ask them to speculate why the bubbles shatter in cold air. You can also invite students to dip their wands into the solution but not blow a bubble. Let them watch as the solution crystallizes across the wand.

### If You Have...Salt

Use It to Demonstrate: How salt is an effective agent in melting ice

What to Do: Have students place an ice cube in a shallow dish of water. Invite them to lay a piece of string across the cube and try to pick it up by lifting the string. Next, have them sprinkle salt over the ice and string and count to ten. This time the cube should stick to the string.

### If You Have...Borax

Use It to Demonstrate: Crystal formations, chemical reactions

What to Do: Have students twist a pipe cleaner into the shape of a snowflake. Tie a piece of string to the snowflake and attach the other end to the middle of a pencil. Now, fill mason jars three-quarters full with boiling water. Add 3 tablespoons of Borax for each cup of water. Place the pipe-cleaner snowflake into the jar, not letting it touch the sides or bottom. (Trim the string accordingly.) Rest the pencil across the top and place the jar somewhere it won't be disturbed. When students look the next day, they should see that tiny crystals have formed on the snowflakes.