Sandsational

Challenge
Summer is nearing an end but there is still time to build a sandcastle! The good news is you don't even need to go to the beach to do so. The beach experiences way too much erosion by wind and rain anyway to keep a sandcastle around for multiple days. Can you think of other ways erosion affects the land or other things? What does all this have to do with this month's challenge? This month, your challenge is to engineer sand so it can withstand the erosion elements of wind and water. You're going to test out different recipes to determine which sand would be best to keep a sandcastle in tact during a windy day or a wet one. What ingredients might we need to do so? How much of each ingredient? How can we test out a recipe before building an entire sandcastle? 

Your sand recipe does have some criteria and constraints. Only the materials provided can be used in your recipe. The same kind of sand should be used when performing tests against each other. Other sands can be used as long as all groups have access to the same sand. Try to change only one variable at a time so fair tests can be done. Use a Dixie cup as the standard size of a brick to measure the effects of erosion.

*This idea and challenge can be further explored in the Advancing STEM Grade 4 Unit, Centuries of Change: Processes That Shape the Earth. 

Materials

• sand
• liquid white glue
• Dixie cups
• non-stick spray
• water
• watering can (shower head spout)
• small fan
• plastic spoons
• mixing bowls

Hints and Tips for Success

1. Provide sample castles for students to improve. These will act as a baseline and starting point for them. Mix together 1 Dixie cup of sand and 3 teaspoons of water. Spray the inside of the Dixie cup with the non-stick spray. Pack the mixture into the cup and let sit. Pack another cup with sand but without mixing in the water. 
2. Turnover the cups to expose the small sand castles. You might have to tear the cup off of the sand. Share the recipes for those two mixtures with the students. Allow the fan to blow on each. Dump about 1 cup of water on each with the watering can. Collect and discuss the data and evidence of each test. Charge students with the challenge.
3. Allow students planning and discussion time by having them experiment with the items to see how they mix together. Students could conduct mini experiments by placing small amounts of the mixing items together to see how they interact in very small doses.
4. After experimenting, allow student groups to plan their recipe of what will go in 1 Dixie cup. Include as many ways to improve their sand castle recipes as needed. 
5. For differentiation, adjust the amount of materials available and allowed to use (limit the amout of glue allowed to be added), add any additional materials, take away certain materials, show them different versions others have created, use different sized cups, use different types of sand. Adjustments could be made to make it more challenging or simpler.
6. Make sure to always standardize their tests when collecting results such as distance fan is from the sandcastle, speed of the fan, amount of water being poured on it, how high the spout is above the sandcastle, ways of collecting data and evidence.
7. Connect to mathematics by discussing measurement, ratios, conversions, etc.
8. Connect to science by discussing erosion, weathering, natural disasters, human preparation for events such as natural disasters, mixtures, solutions, matter, etc.