# Math Labs

These hands-on projects were compiled by Steve Waldhorn. He is a teacher at Green Acres School in Rockville, Maryland. We'll add additional labs from time to time, so definitely check back!

Teachers, share your own favorite Math Labs with us! Send to: MathMag@scholastic.com

If we use your idea, we'll send you a *MATH* Magazine T-shirt!

**Preparation:**

You’ll need one ruler per pair of students.

**Objective:**

Calculate reaction “time” as a function of distance the ruler falls before it can be caught.

**Project:**

- Divide students into pairs.
- One student holds the ruler by its end between the other student’s separated thumb and index finger. (Make sure the ruler is facing the same way for each attempt.)
- The student releases the ruler and both carefully measure at what increment the second student is able to catch the ruler.
- Do this ten times and calculate an average “time” (the inch or centimeter mark where the student caught the ruler).
- Also find an average value for the entire class, for boys only, girls only, or other parameters.
- Graph results in a scatter plot.

**Follow-up:**

- How is the measurement of centimeters or inches related to seconds?
- When might it be critical to have a quick reaction time?
- Would the experiment be fair if a student was allowed to drop the ruler by herself or himself? Why or why not?

**Preparation:**

- You’ll need 200 dominoes per group of 3–4 students. If you do not have dominoes, you could use old VHS tapes or videotape cases. (You’ve been wondering what to do with them since switching to DVDs!)
- You’ll also need stopwatches (1 per group).

**Project:**

- Divide students into groups of 3 or 4.
- Challenge students to determine—using only the provided dominoes, stopwatch, and their brains—how long it would take 280,000 dominoes set up in a single file to fall.

**Follow-up:**

- Did the dominoes fall at a steady rate?
- How would this affect your answer?
- What could you do to account for errors caused by acceleration in the rate of fall?
- Would a curved pattern affect the rate of fall?

**Preparation:**

- Cut 10 x 10 cm squares of aluminum foil (about 10 per student)
- Have paper clips handy (about 100 per group of 3–4 students)
- Have plenty of paper towels for cleaning up
- Have a container to float barges for each group about 4–5 inches deep, maybe 12" long, and 4" wide)

**Project:**

- Divide students into teams of 3 or 4 and tell them the challenge is to construct the barge that supports the largest number of clips for 10 seconds.
- They will have one period (45 minutes) to practice and construct their final barge.
- Only one piece of foil for each barge.
- Wet clips weigh more than dry ones.
- Teacher must be present for any “official” count and compliance with the 10-second rule.

**Follow-up:**

- What property have we measured?
- Would it be different if we used milk or oil?
- What if we could use silver, copper, or gold foil?
- What if we used a square of foil that was 30 x 30 cm? How many more clips would we expect to hold? Why?

**LAB #4: ESTIMATION SCAVENGER HUNT**

**Preparation:**

Answer these questions yourself before sending the kids out!

**Project:**

- Divide students into teams of 2 or 3.
- Each team will find approximations and correct orders of magnitude for the following sorts of items. They should write down their predictions before going on the scavenger hunt.
- How many basketballs, footballs, soccer balls, softballs, and dodgeballs are in the school gymnaisum?
- How many brushes are there in the art room?
- How many percussion instruments in the music room?
- How many cars in the parking lot?
- How many bricks on the east side of the school building?
- How many pencils in the school?
- Add a few items unique to your school.

**Follow-up:**

- Time each group with a stopwatch and award points for accuracy.
- Compare their predictions with their results.
- Have an estimation party as a celebration (e.g. how many M&Ms are in the jar? How many would that be for each student?)