Before we start our activity today, we are going to learn the difference between a demonstration and an experiment. A demonstration is a visual representation of a scientific concept. For an activity to become an experiment, you need to have a variable. An experiment is defined as a scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact. To complete an experiment, you must have a variable, or change, that you are observing.
Check out this link to learn more about what variables mean!
- Controlled variable
- Independent variable
- Dependent variable
Today, you are going to see how water absorbs heat.
Water is unique in that it has a high capacity for heat absorption. When heat is added to water, water molecules begin to move faster and hydrogen bonds break.
Check out this video to see what you’ll be doing today!
YOU WILL NEED:
- Two balloons
- Water Pitcher
- An adult to help you
Here’s what to do!
- Have an adult strike a match and light the candle.
- Blow up the first balloon. This is your control variable.
- PREDICT: What will happen when you touch the flame of the candle to the balloon?
- With an adult around to help you, bring the flame of the candle to the edge of the balloon. What happened? Record your observation.
- This time, you are going to do something a little different. You are going to add water to the balloon. This is your independent variable. Use the funnel to help you get water into the balloon--place the funnel in the neck of the balloon and pour water from the pitcher into the funnel.
- Blow the balloon up and tie it.
- PREDICT: What will happen when you touch the flame of the candle to the balloon? Will you get the same result as last time? Why or why not?
- If your candle has gone out, use a match to relight it. Bring the flame of the candle to the bottom of the balloon where the water has settled. What happens? Record your observations.
- Why did the second balloon behave differently than the first balloon?
- How could you enhance this experiment? As you learned earlier, good experiments include measurable variables. What you’ve done so far is not very measurable. How could you improve the experiment? Your independent variable is the water you put in the balloon. Would changing the amount of water affect how long the balloon takes to pop? Check it out! Try using different amounts of water and then timing how long it takes for the balloon to pop. Record you observations and make a graph to represent your findings.
Follow-up Questions: What was your controlled variable in this experiment? What was your independent variable? What was your dependent variable?