UNIT: MEASUREMENT

ACT-Based Science: Temperature and Expansion Measurements
OBJECTIVE:

This activity helps students understand how temperature changes affect material expansion and contraction. By using precise measurement tools, students will track small length changes and analyze the relationship between temperature and material properties in real-world applications like engineering and construction.

Science Thinking Challenge:

How does temperature affect the dimensions of different materials?

Why do engineers need to account for thermal expansion in construction?

What are some real-world applications of thermal expansion principles?

Applied Science Problem:

A metal rod is 10.0 cm long at 20°C. After being heated to 100°C, its length increases to 10.2 cm. What is the percentage increase in length?

0.5%

1.0%

2.0%

5.0%

MATERIALS NEEDED:

Measurement tools: Digital calipers, rulers

Metal and plastic rods

Safe heat source (hot water, heat lamp)

Worksheet templates for data collection

STUDENT DIRECTIONS:

Goal:

In this activity, you'll explore how temperature changes affect the size of materials. You'll use digital calipers or rulers to precisely measure the length of metal and plastic rods before and after heating. This experiment will help you understand thermal expansion, a key concept in engineering, construction, and the ACT Science section.

Step 1: Gather Your Materials:

One metal rod and one plastic rod (same initial length)

A digital caliper or ruler for precise measurement

A safe heat source (hot water bath, heat lamp, or warm pad)

Your Temperature & Expansion Worksheet

Step 2: Record Room Temperature:

Use a thermometer to measure the current room temperature.

Record this value on your worksheet.

Step 3: Measure at Room Temperature:

Measure the length of the metal rod to the nearest millimeter (or 0.01 cm if using calipers).

Repeat for the plastic rod.

Record your results in the “Before Heating” section of the worksheet.

Step 4: Gently Heat the Rods:

Place both rods near or in a safe heat source for 3–5 minutes.

Do not place calipers or rulers in the heat source.

Ensure both rods are exposed to similar temperatures.

Step 5: Measure After Heating:

Carefully remove the rods (with tongs or heat gloves if needed).

Re-measure the lengths of the rods immediately.

Record the “After Heating” lengths on your worksheet.

Step 6: Calculate Change and Percent Increase:

Subtract the original length from the heated length for each rod.

Use this formula to calculate percent increase in length:

Record all calculations on your worksheet.

Analysis and Reflection

Answer the following analysis questions on your worksheet or in small groups:

Which rod expanded more — metal or plastic?

Why do you think the two materials responded differently to heat?

How does temperature affect the physical dimensions of materials?

Why do engineers and architects need to consider thermal expansion when designing bridges, buildings, or pipelines?