Lesson 3: Caffeine Effects

Caffeine is contained in many beverages consumed every day by most people. Coffee, tea, soft drinks and a number of other sources place caffeine inside our bodies. How do you think that caffeine affects a person’s body? Try out your ideas on your friendly water flea.

Doing the science

1. Start the Water Flea Simulation by clicking on the "Sim" tab.
2. You can use the Timer Counter on the left side of the screen to find the water flea’s heart rate or you can use a stopwatch. To use the Timer Counter, click the "Start" button, then click the "Click Me" button each time the flea’s heart beats. After getting in the rhythm of the beats, click the "Stop" button and the flea’s heart rate will be displayed in beats per minute in the space below the buttons. Record this value (normal heart rate) and the gender, feeding status, and mass of the flea in Table 1 below.
3. Click the "Caffeine" button, then select the "Single Dose" button. Count and record in Table 1 the flea’s new heart rate. Click the "Clear" button.
4. Click the "Caffeine" button, then select the "Double Dose" button. Count and record in Table 1 the flea’s new heart rate. Click the "Clear" button.
5. Click the "Feed Flea" button and repeat steps 2 – 4. Make sure to record your data in Table 1.
6. Select a Male water flea and repeat steps 2 – 5. Make sure to record your data in Table 1.