Heat

Nolan picks up a book from his desk and hands it to his teacher. His teacher sets the book down and slides it across a table. Which action produces the most heat?

• sliding the book across a table

• handing the book to his teacher

• setting the book down on a table

• picking the book up from his desk

When your hands feel cold, it can help to rub them together very quickly. This can make your hands feel warm. Why does rubbing your hands together make them warm?

• Rubbing your hands together can cause a fire that produces heat.

• Moving your body can cause your heart rate to speed up and warms the blood.

• Rubbing your hands together causes friction which can produce heat.

• Rubbing your hands together causes energy which produces heat.

A light bulb in the table lamp goes out. Carrie quickly replaces it and burns her fingers when removing the light bulb. Why does this happen?

• A light bulb reflects light, which causes her fingers to burn.

• A light bulb absorbs heat from the air.

• A light bulb produces light and also gives off heat.

• A light bulb still has electricity running through it which causes heat.

Several students in a class measured the temperature in different places around the school at 10:00 a.m. The results are shown in the table. What variable below BEST explains why the temperatures are different?

• Some of the thermometers did not work well.

• Temperature is difficult for students to measure.

• Some of the thermometers were placed in shaded areas and some in sunny areas.

• Temperature is often different if the thermometer is moved just a few feet away.

Mitch read that rubbing skin on skin creates more friction than rubbing skin on paper. How could he best test this?

• He could rub his hands on a doorknob, then on paper.

• He could rub his hands together, then on a piece of paper on a table.

• He could rub two pieces of paper together.

• He could rub his hands together inside his classroom, then outside.

Kayla’s family is cooking lunch on an outdoor grill. Which items are giving off both light and heat?

• the coals and the air

• the food and the flames

• the grill and the food

• the coals and the flames