slip and slide salt truck experiment
Here's what you'll need for older toddlers and preschoolers:
You'll need to freeze two large baking trays (with low sides) filled with 1½ inches of water overnight, toy cars with rubber wheels, a bowl of iodized salt, and two cups of snow (you can make snow with several ice cubes chopped up in a blender if necessary); the book Ice Is...Whee! by Carol Greene; and two sheets of wax paper per child along with room for skating, a CD of waltzing music and a player is optional.
Here's How: Plan to do this activity on a snowy morning when the start of the day has been delayed or on the day children return to the school or program after it was canceled due to dangerous road conditions. For those of you living in temperate climates, pay attention to weather elsewhere in the county and if there is a big snow or ice storm reported on the news or newspaper, do this activity. On these days, trucks spread salt everywhere on the roads and the children may see them and/or hear adults talking about them driving through neighborhoods to "treat the roads." Gather a small group of children together on the rug or group meeting area and read the book Ice Is...Whee! by Carol Greene. We suggest you help the children safely experience the feeling of slipping and sliding. If you do not live in area where ice and snow are a regular occurrence, the children may not realize how it feels to slip and slide on a slick surface. To help them better understand the feeling, let the group take off their shoes and slide carefully around on the bare floor or show the children how to stand on two pieces of wax paper and "glide" on carpet. We recommend that you do this with only a small group at a time and remain close by to "spot" and catch any children who really do slip. During the open play time, center time or the "work period" in the day, invite small groups of children to visit an activity table and experiment with salt and slipping toy cars. Set the frozen tray on the table with the bowl of salt and the toy cars. Ask the children to help sprinkle some snow on top of the trays and let each child touch it. Encourage the children to talk about what they know about ice and snow and discuss how it feels, looks, and what happens when cars drive or people walk on it. Ask if the children have noticed salt trucks on the road or heard anyone talking about them. Let the children help "clear" a road on each tray and give the children turns pushing, sliding and driving the toy cars on the roads.
Then once all children have had time to explore, ask them to help sprinkle salt on one tray (but not the other) - just like the salt truck do! As you watch the salt sit on the ice, ask children to predict what might happen, and talk about what does. Let the children drive a different car on each tray to compare the slippery roads. Ask them to guess why trucks drive around spreading salt on snowy and icy days. Help them understand that it helps melt the ice and make the roads safer for cars.
Extend the Slip & Slide Salt Truck Experiment by placing both baking trays outdoors, let the children continue to play and pretend to drive the car on them. Check the trays periodically with the children to see what happen to each as they remain out in the cold. After an hour or so (the rate of melting depends on many things, including the amount of salt used), reconvene the group. Ask them what has happened to the ice and if the salt made a difference.