Engineering Challenge!

Materials List:

• One-pint jar with lid
• Clear straws
• Modeling clay
• Rubbing alcohol and food coloring
• Water
• Index cards
• Real thermometer to calibrate the one you make with accurate temperature readings!

Instruction Steps:

1. Fill the jar with equal parts water and rubbing alcohol about ¼ of the way up the jar.
2. Add a few drops of food coloring to color the temperature-sensitive liquid.
3. Secure the cap and shake the jar to ensure the food coloring is evenly dispensed in the liquid.
4. Punch a hole with a pen in the center of the cap, allowing the straw to feed through.
5. Position the straw so that is dips into the liquid but does not touch the bottom of the jar.
6. Use the modeling clay to wrap around where the straw enters the lid to create an airtight seal.
7. Use an index card taped to the straw to show temperatures on your thermometer. Use a thermometer to help correctly mark the index card with the temperatures.
8. Your thermometer is now ready to record some data!

Goal 2: Record Data

1. Place your thermometer outside in a spot that will best record daily temperatures. Pick a spot that will get the most sun.
2. Use the data sheet entitled “Thermometer Lab Sheet” to record your temperatures 2 times a day for a week.
   1. 8:00
   2. 1:00
3. Create a bar graph to represent the recorded temperatures.