Gum Mass versus Time

Purpose

In this lab, you will be chewing gum to see how the mass changes over time. Data will be collected and entered into a spreadsheet so a graph can be generated.

Background

In physics, we are asked to look for relationships between variables. It is good to focus on only two at a time, the independent and the dependent (Music Video Describing the difference). In general when studying relationships between variables you have 3 different possibilities.

• Direct Relationship - When one variable increases, it causes an increase in the other.
• Inverse Relationship - When one variable increases, it causes the other to decrease.
• No Relationship - When one variable increases, there is no change or a random change in the other.

In this lab, time will be the independent variable and mass will be the dependent. It is good practice to try and predict the relationship between the variables before you start.

What kind of relationship do you think mass and time will have?

Materials

• 3 pieces of bubble gum
• Triple beam balance or electronic scale
• Stopwatch

Procedure

1. Find the mass of one of the wrappers from the gum. This will be used as a weighing dish for all trials. Record this in your notes. Watch your significant figures when reading the balance.
2. Find the mass of all three pieces of gum and the wrapper at the same time. This will be the mass for zero time. Watch your significant figures when reading the balance.
3. Chew all three pieces of gum at the same time for one minute.
4. Find the mass of the gum and the wrapper and record this for the 1 minute time.
5. Continue to chew the gum for one minute and find the mass until you have chewed for a total of 15 minutes.

Calculations

Create a spreadsheet that has the mass of the wrapper in one cell and the times and masses in two columns. The masses include the wrapper so this will be the first calculation that we will do after setting up the spreadsheet.

In a new column, title it Mass of Gum (g). Below the title, start a formula to subtract the wrapper’s mass from the gum and wrapper mass. You will need to use $s before the letter and the number for the wrapper’s mass cell in the formula before you fill it down. Example: =D2-$A$2 

Create a graph with time as the independent variable and mass of gum as the dependent. Place this graph as its own sheet in the file.

Analysis and Discussion

• Did the data follow what you predicted?
• How did your graph compare with others?
• What do you think was the cause of the changes between the two variables?