1/20/2027

Morning Announcements

Morning Meeting Agenda

Mon · Social Studies Tue · Literacy Wed · Science Thu · Math Fri · ROAR + Houses
Science of the Day

Why we put salt on icy roads

When ice hits Chattanooga, trucks spread salt on the roads. Salt isn’t hot. It doesn’t burn anything. So how does it melt ice?

Here’s something amazing: water can change into three different things! It’s still water — it just looks completely different.

The three states of water: ice, water, and steam
Let’s talk
  • What turns ice into water? What turns water into steam?
  • Where have you seen steam at home?
  • If you leave an ice cube on the counter, what happens? Why?
Reveal the answersHide the answers
Heat does it both times! Warm it up and ice melts into water. Warm it a lot more and water turns to steam. Take heat away and it goes back the other direction. Steam shows up from hot showers, boiling pots, and your breath on a cold day!
Try it

Be the water! Freeze like ICE — stiff and still. Now melt into WATER — wiggle loose and floppy. Now become STEAM — float your hands up high and drift away!

Water normally freezes at 32°F. Salt changes that number — it makes water need to be colder before it can freeze. Scientists call this freezing point depression.

Salt lowers the freezing point PLAIN WATER 32°F Freezes at this temperature → add salt SALT WATER 15°F Has to get much colder to freeze

Same air temperature — different result.

So on a 25°F road, plain water is frozen solid. Add salt and that same water can’t stay frozen — because 25° is no longer cold enough.

Let’s talk
  • Salt has no heat of its own. So where does the energy to melt the ice come from?
  • Predict: if it drops to 5°F, will road salt still work? Why or why not?
  • The ocean is salt water. What does that tell you about why oceans rarely freeze solid?
Reveal the answersHide the answers
Salt doesn’t add heat — it changes the rules. Ice always has a thin film of liquid water on it; salt dissolves into that film, and salt water can’t refreeze at 32°. So melting wins over freezing. And no — at about 15°F and below, road salt stops working, which is why cold-weather cities switch to sand for traction or use different chemicals. Ocean water freezes around 28°F instead of 32°, part of why polar seas stay liquid under ice.
Try it

Design the experiment! With a partner, plan a test to prove salt melts ice faster. What’s your control? What’s the one variable you’d change? What would you measure? A good experiment changes one thing only.

Additional Notes/Activities

If additional activities are needed for the Morning Meeting, they will be added here.