Yesterday we talked about 32° and 15°. But temperatures can go below zero — and that’s where a lot of people’s math gets shaky.
A thermometer tells us how hot or cold it is. The higher the red line goes, the warmer it is!
Let’s talk
Which thermometer shows the warmest day? How can you tell?
What would you wear on the coldest day? What about the hottest one?
Water turns to ice at 32°. Which of these days would have ice?
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The 90° day is warmest — tallest red line! You’d need a coat, hat, and gloves at 20°, but shorts at 90°. And only the 20° day would have ice, because 20 is colder than 32.
Try it
Be a thermometer! Crouch down low for a COLD day. Stand up tall for a HOT day. Now I’ll call out temperatures — you show me with your body! 90 degrees! 20 degrees! 50 degrees!
Zero isn’t the coldest it gets — it’s just a mark on the scale. Below it, numbers keep going with a minus sign. And the number line is the key to reading them.
Let’s talk
Which is colder, −10° or −20°? Use the number line to justify your answer.
It’s 15° at midnight and drops 25 degrees by dawn. What’s the temperature?
Morning low is −5°, afternoon high is 18°. How many degrees did it climb?
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−20° is colder — it’s farther left on the line. This is the classic trap: with negatives, the bigger number is the smaller value. Starting at 15° and dropping 25 lands you at −10° (down 15 to zero, then 10 more below). And from −5° up to 18° is 23 degrees — 5 to reach zero, then 18 more. Count the distance through zero, not around it.
Try it
Where else do negatives live? With a partner, name three real places you’d see a number below zero — think elevators, bank accounts, elevation, sports. Then explain what “zero” means in each one. It’s different every time.
Additional Notes/Activities
If additional activities are needed for the Morning Meeting, they will be added here.