Marshmallow and Syringe Activity

Marshmallow and Syringe Activity

MATERIALS:

Large syringe and plunger

Marshmallow

EXPLORE:

Put a marshmallow into the large syringe. Insert the plunger and press it until it is right above the marshmallow. Seal the tip of the syringe by pressing your fingertip firmly against it. Pull outward on the plunger (do not pull the plunger completely out). Observe what is happening. Now, press the plunger back down. Again, observe what is happening.

1. Draw two pictures of the model: for the first picture, draw the syringe and plunger vertically aligned with the plunger completely depressed, like when you started. Then, draw a picture of the model, again vertically, with the plunger pulled outward.

“ Lamp, Smoke and ice cubes lab” adapted from a lesson found atscience-class.net - 2002

CONCEPT INVENTION

1. With the plunger in place and your finger on the end of the syringe tip, The system inside the syringe was closed: nothing could get in, nothing could get out. As the plunger was pulled outward, did the number of air molecules increase, decrease, or stay the same? Stayed the same.

2. What happened to the distance between the air particles when the plunger was pulled? The distance between the air particles increased.

3. What happened to the density of the air in the tube when the plunger was pulled?

The density of the air in the tube decreased as the plunger was pulled.

4. What happened to the air pressure inside the tube as the plunger was pulled?

The pair pressure inside the tube decreased as the plunger was pulled

5. What happened to the marshmallow as the plunger was pulled?

The volume of the marshmallow increased as the plunger was pulled.

6. Look at your pictures. Title the entire diagram “Atmosphere.” What do you think the marshmallows represent? Use your answer to label the marshmallows in the diagrams in your spiral. The marshmallows represent clouds.

7. In the picture on the left, the plunger is completely down and the air particles are packed closely together on top of the marshmallow. Label this diagram “High Pressure.” Label the picture on the right “Low pressure.”

8. Explain why you think the marshmallow expanded in the low pressure tube. Because of diffusion, the air particles inside the marshmallows tried to leave the marshmallow to fill the new space in the syringe. This caused the marshmallow to swell.

TERM INTRODUCTION:

All the concepts from these demonstrations work together with numerous other factors to create the earth’s weather. In the syringes, you have modeled how high pressure and low pressure near the Earth’s surface influence precipitation.

1. Think about convection. Think about the water cycle. How do you think that convection is involved in thunderstorm formation? Convection means “to carry with…”. As air is heated at the Earth’s surface and starts to rise, moisture in the air can be carried upward, causing clouds to be formed by convection.

2. Think about a time when you were under intense pressure. Explain how you felt. Trapped, uncomfortable, want to hide, etc.

3. How do you think clouds respond to being under intense pressure? Under high pressure, the clouds can’t build up into big storm clouds very well, because the high pressure pushes down on them and keeps them from growing up into the cold upper atmosphere, where they could cool and condense and form big storms.

APPLICATION:

1. Consider a hurricane. The center of the hurricane is an intense area of low pressure. Explain how this makes sense, using the syringe model. Because of the low pressure and the warmth of the ocean floor, Clouds around the center of a hurricane can convect upward very easily. This creates lots of intense storms near the center of a hurricane.

2. Texas has undergone an intense and lingering drought. Use the syringe model and anything you may have heard on TV and explain why the Texas drought has continued. Explain why clouds formed, but were unable to grow into thunderstorms, most days. The news stations all summer said we were under “high pressure.” The high pressure did not allow any clouds that tried to form from reaching high into the atmosphere, condensing, and precipitating in our area. This persisted for months, causing a severe drought.

“ Lamp, Smoke and ice cubes lab” adapted from a lesson found atscience-class.net - 2002