Before your Visit
Vital Vocabulary!
If your students need definitions for words used in these online activities, look here! Definitions are provided that specifically pertain to these activities. Teachers may choose to teach a separate vocabulary lesson of their own design. Alternatively, students may be given a vocabulary list to use as a reference tool.
Stretching the Limits Activity (approx. time: 1 hour)
Teachers! Students will need to complete this activity before moving on to "Making a Mockery of Work." In this activity, students will construct rubber band scales to be used in the "Mockery" activity. Students will also have the opportunity to learn to use the scales.
Students can do this activity as individuals or as small groups. Student lab instructions are available for distribution.
Each student or group of students will need the following materials:
paper clip
30 cm ruler
scissors
masking tape
medium weight rubber band
18 " piece of string
group of objects(teacher selected)*
*NOTE: students may rotate these objects among the groups if needed
Required Teacher Preparation:
Construct a rubber band scale, using the directions given below. Select a group of objects for the students to use in the experiment. Using the rubber band scale the teacher has constructed, measure the effort used to lift the object straight up until it is free of the tabletop. Record the effort needed for to lift each of the objects and list the objects from least effort needed to most effort needed.
Lab Procedures:
Establish set: (class discussion)
- Ask students to brainstorm objects that can be used to take measurements.
- Teacher records items listed on the board.
- Ask students if a rubber band could be used to measurement anything?
- Explain to the students that they will be building and using rubber band scales.
- Instruct students how specific the measurements taken should be. (Ex: to the nearest centimeter, millimeter, etc.)
- If dividing students into groups, do so at this point.
Strategies/Tasks/Steps: (student directives from lab instructions)
- Make one cut in the rubber band to make one long piece.
- Tie a paper clip to one end of the rubber band.
- Tie the string to the opposite end of the paper clip.
- Hold the paper clip so that the tip is at the 9 cm mark on the ruler.
- Drape the rest of the rubber band the length of the ruler so that the end hangs over the end of the ruler (the 0 mark end)
- While holding the paper clip at the 9 cm mark, tape the other end of the rubber band securely to the back of the ruler. Don’t stretch the rubber band.
- For each object: attach the object to the rubber band scale using the string at the end of the paper clip.
- Slowly lift the rubber band scale straight up so that the object is lifted off the table or desk.
- Observe how far the rubber band stretches. Find the number at the bottom tip of the paper clip and record it on the lab sheet next to the name of the object.
- Repeat steps 7, 8 and 9 for each of the objects given.
- After all objects have been tested, order the objects from least to greatest in the amount of effort needed to lift them.
Closure: (class discussion)
- Ask students to list the items in correct order. Make sure students are starting with the items requiring the least amount of effort to lift.
- Students will store rubber band scales in safe location for use in a later lesson.
Making a Mockery of Work (approx. time: 1 hour)
Teachers! Students will need to complete the "Stretching the Limits" Activity before moving on to this activity. Students will be using the rubber band scales constructed in the "Stretching" Activity.
Students can do this activity as individuals or as small groups. Student lab instructions are available for distribution.
Objective: Inclined Planes make it easier to lift or lower weight by increasing the distance traveled.
Each student or group of students will need the following materials:
Ziploc bag
35 marbles (or other compact material weighing about 2 lbs.)
string (30 cm long)
5-6 books
long smooth board or cookie sheet
rubber band scale (assemble during previous class period if necessary)
Hypothesize: Have students make an educated guess on what the experiment will teach them. Make sure they record their hypothesis.
Lab Procedures:
- Put the marbles into the Ziploc bag. This is the load.
- Tie one end of the string to the paper clip on the scale.
- Tie the other end of the string to the neck of the sandwich bag.
- Stack the books on one end of the table.
- Place the load on the table and slowly lift it to the height of the stack of books by lifting the ruler (the rubber band will stretch down the front of the ruler)
- Record how far the rubber band stretches. Find the number by the bottom tip of the paper clip on the scale and record it.
- Place one end of the board on the books to make a ramp. The other end of the board rests on the table top.
- Place the load at the bottom on the ramp and slowly move it up the ramp by pulling the scale up the ramp (the rubber band will stretch down the ruler)
- Observe how far the rubber band stretches. Find the number at the bottom tip of the paper clip and record it.
Tidbits for Thought:
Teachers! These "tidbits" can be used in many ways. They could serve as a homework extension, addition lab questions, or as classroom discussion questions.
- On the rubber band scale, how does the amount of stretch in the rubber band indicate the amount of effort being used to move the load?
- Try each of these variations:
- How would the numbers change if more books were added to the stack?
- How would the numbers change if several books were taken out of the stack?
- How would the numbers change if more marbles were added to the bag?
- How would the numbers change if marbles taken out of the bag?
Conclusions: The rubber band stretched farther when lifting the load straight up than when the load was pulled up the ramp. This shows that using an inclined plane reduces the amount of effort needed to lift a load.
