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Activity: Why does sand at the beach feel hot, even when the water feels cool?

Make science come alive in your classroom with this free hands-on activity aligned to high school NGSS standards.

Activity: Why does sand at the beach feel hot, even when the water feels cool?

If you’ve ever been to the beach on a sunny day in the middle of summer, you’ve probably experienced how hot the sand feels on your bare feet, even though the water temperature feels cool. Maybe you’ve had a similar experience walking on the hot concrete of a pool deck on your way to a refreshing swim.
Even though the same sunlight is shining on the water and the sand or concrete, the temperature of the water doesn’t rise as much. What causes this difference? What factors affect how much the temperature of a substance changes when a given amount of thermal energy is transferred into or out of it? In this activity, you’ll investigate those factors and use your knowledge to develop an explanation.
Sand and water at the beach on a sunny day


This activity is designed to be completed in two or three 45-minute class periods, with additional time required for follow-up creative projects. The activity consists of the following parts:
  • Setting the stage—Students review fundamental concepts related to heat transfer. (20 minutes)
  • Investigation (Part 1)—Students investigate what happens when water samples of different temperatures and masses are combined. Students analyze and interpret their experimental data to draw conclusions about the effects of these variables on thermal equilibrium temperature when heat transfer occurs. (45 minutes)
  • Investigation (Part 2)—Students investigate what happens when samples of different materials with the same mass and initial temperature are added to room temperature water. Students analyze and interpret their experimental data to draw conclusions about the relationship between the specific heat capacity of a substance and the degree to which its temperature changes when a given amount of heat is transferred per unit mass. Students also use their data to calculate the experimental specific heat capacity of one of the materials tested. (45 minutes)
  • Let's get creative!—Students apply their knowledge of heat transfer to create a pamphlet that explains why sand at the beach feels so much hotter than the water, even though both are experiencing the same solar radiation on a sunny summer day. (45 minutes)
  • Keep creating!—Students can choose from additional project ideas. Each project encourages students to combine scientific knowledge with creativity to produce something new.

Download the worksheets and get started today!

You can print out this activity or upload it to a digital classroom.

NGSS performance expectations

HS-PS3-4. Plan and conduct an investigation to provide evidence that the transfer of thermal energy when two components of different temperature are combined within a closed system results in a more uniform energy distribution among the components in the system (second law of thermodynamics).

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