Activity 5 Investigating Weight Gain and Weight Loss

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

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

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

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

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

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

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

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

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

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?

A Student Drinking Water Gas Liquid Student g g 600 g g 50. 0 kg g Matter Inputs Gas Liquid Student Matter Outputs Process: What is your prediction of the weight of the student after s/he drinks the water?

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

A Student Drinking Water Gas Liquid Student g g 600 g g 50. 0 kg 50. 6 kg Matter Inputs Gas Liquid Student Matter Outputs Process: Prediction that follows Conservation of Mass

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

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?