Activity 5: Investigating Weight Gain and Weight Loss

Conservation of Mass (Except in nuclear reactions) the total mass of of the materials (solids, liquids, and gases) involved in any change in matter stays the same.

Tracing Matter Process Tool Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid g g g g g

Wetting a Sponge Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid 30 g 20 g g g g What is your prediction of the weight of the wet sponge?

Wetting Vermiculite What is your prediction of the weight of the wet Vermiculite? Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid 40 g 30 g g g g

Wetting a Sponge Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid 30 g 20 g g 50 g g Prediction that follows Conservation of Mass

Wetting Vermiculite Prediction that follows Conservation of Mass Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid 40 g 30 g g 70 g g

Your Predictions and Measurements When you measured the mass of the wet sponge and Vermiculite, how accurate were your predictions? Do you think conservation of mass applies to wetting the sponge and Vermiculite? Did the sponge and Vermiculite gain weight when you added water?

Drying a Sponge What is your prediction of the weight of the dry sponge? What happened to the mass of the water? Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid 50 g g g g g

Drying Vermiculite What is your prediction of the weight of the dry Vermiculite? What happened to the mass of the water? Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid 70 g g g g g

Drying a Sponge Prediction that follows Conservation of Mass Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid 50 g g 20 g 30 g g

Drying Vermiculite Prediction that follows Conservation of Mass Matter Inputs Matter Outputs Gas g Liquid Solid Process: Gas Liquid Solid 70 g g 30 g 40 g g

Your Predictions and Measurements When you measured the dry mass of the sponge and Vermiculite, how accurate were your predictions? Do you think conservation of mass applies to drying the sponge and Vermiculite? Did the sponge and Vermiculite lose weight when you dried them out?

Watering Your Plants What is your prediction of the weight of the cup, soil, and plants after watering? Matter Inputs Matter Outputs Gas g Liquid Plant in cup Process: Gas Liquid Plant in cup 150 g 10 g g g g

Watering Your Plants Prediction that follows Conservation of Mass Matter Inputs Matter Outputs Gas g Liquid Plant in cup Process: Gas Liquid Plant in cup 150 g 10 g g 160 g g

Final Discussion Questions 1.Look back at the questions you answered before starting this activity. Do you now have different answers to any of the questions? 2.Do you think that conservation of mass applied to all the changes that you measured? Why were the masses you measured before and after sometimes different? 3.You can see that the measured weight of something can vary a lot depending on how much water is in the system. How could we tell whether plants are gaining dry weight (not just water) when they grow?