Activity 5: Investigating Weight Gain and Weight Loss
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Transcript of 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
Matter Inputs
Matter Outputs
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solidg
g
g
g
g
Wetting a Sponge
Matter Inputs
Matter Outputs
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solid30 g
20 g
g
g
g
What is your prediction of the weight ofthe wet sponge?
Wetting Vermiculite
What is your prediction of the weight ofthe wet Vermiculite?
Matter Inputs
Matter Outputs
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solid40 g
30 g
g
g
g
Wetting a Sponge
Matter Inputs
Matter Outputs
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solid30 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
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solid40 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 ofthe dry sponge?What happened to the mass of the water?
Matter Inputs
Matter Outputs
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solid50 g
g
g
g
g
Drying Vermiculite
What is your prediction of the weight ofthe dry Vermiculite?What happened to the mass of the water?
Matter Inputs
Matter Outputs
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solid70 g
g
g
g
g
Drying a Sponge
Prediction that follows Conservation of Mass
Matter Inputs
Matter Outputs
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solid50 g
g
20 g
30 g
g
Drying Vermiculite
Prediction that follows Conservation of Mass
Matter Inputs
Matter Outputs
Gasg
Liquid
Solid
Process:
Gas
Liquid
Solid70 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?
A Student Drinking Water
What is your prediction of the weight ofthe student after s/he drinks the water?
Matter Inputs
Matter Outputs
Gasg
Liquid
Student
Process:
Gas
Liquid
Student50.0 kg
600 g
g
g
g
Watering Your Plants
What is your prediction of the weight ofthe cup, soil, and plants after watering?
Matter Inputs
Matter Outputs
Gasg
Liquid
Plant in cup
Process:
Gas
Liquid
Plant in cup
150 g
10 g
g
g
g
A Student Drinking Water
Prediction that follows Conservation of Mass
Matter Inputs
Matter Outputs
Gasg
Liquid
Student
Process:
Gas
Liquid
Student50.0 kg
600 g
g
50.6 kg
g
Watering Your Plants
Prediction that follows Conservation of Mass
Matter Inputs
Matter Outputs
Gasg
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?