🧊 What melts ice fastest: salt, sugar or sand?

My hypothesis

If I change what is sprinkled on the ice, then how long the ice cube takes to melt will ______, because ______.

🔊 You fill in the blanks. Think about what each one does when it touches the wet skin of water on the ice. A guess is a good because: the test finds out.

Change, measure, keep the same

Scientists call the thing you change the independent variable and the thing you measure the dependent variable. The things you keep the same are the controls: if one of them changed too, you wouldn't know which change made the difference. Try each of the 4 levels 3 times.

What you need

• 🧊 Ice cubes, all from the same tray: 4 cubes for each try
• 🧂 Salt
• 🍬 Sugar
• 🏖️ Sand (from a sandbox, or play sand)
• 🍽️ Small plates or saucers, all the same: 4
• 🥄 Measuring spoons
• ⏱️ A stopwatch or a kitchen timer
• 🖍️ Crayons or markers

Steps

1. Put four plates side by side and label them: nothing, salt, sugar, sand.🔊
2. Put one ice cube from the same tray on each plate.🔊
3. Sprinkle a teaspoon of salt, sugar or sand on the right cube.🔊
4. Start the timer.🔊
5. Check every 5 minutes and write down which ones are still ice.🔊
6. Write down the time when each cube is all water.🔊
7. Do the whole test two more times.🔊
8. Draw a bar for each one. Which melted the ice fastest?🔊

Every step is one you can do yourself, with a grown-up nearby. Write each number down straight away, in the table below, so nothing is lost.

Your results table

From 4th grade, add the tries for each level and divide by how many there were: that's the mean, and it goes in the last column. Then draw a bar graph, one bar for each thing you tried.

Why it works

🔊 Salt dissolves into the thin skin of water on the ice and makes it harder for that water to freeze again, so the ice keeps melting. Sugar does this too, but less, because a spoon of sugar breaks into far fewer bits in water than a spoon of salt. Sand doesn't dissolve at all, which is why roads use sand for grip and salt for melting.

Going further (7th and up): Change a second thing: try 1, 2 and 3 teaspoons of salt, and graph how the melting time changes.

Board layout

This project at your grade

From 4th grade up, the table gets a mean column. See every project for 2nd grade, or print a blank results table.

What a judge will ask

• What did you change, and what did you measure? I changed what is sprinkled on the ice and measured how long the ice cube takes to melt, in minutes.
• What did you keep the same, and why does that matter? I kept ice cubes from the same tray and the same teaspoonful sprinkled on the same, so the only difference was what is sprinkled on the ice.
• How many times did you test it? 3 times at each of my 4 levels.
• If you did it again, what would you change or test next? I'd try 1, 2 and 3 teaspoons of salt, and graph how the melting time changes.

Make it yours

Keep this project on this device and Peabody counts down to your fair day, with a plan for each day. Nothing is sent anywhere.

Try next

• 🥚 How much salt does it take to float an egg?3rd–7th grade · 1 day of testing · free🧪 Water, ice and mixing · 🧂 Kitchen things
• ☀️ Where does a puddle dry fastest: sun, shade or wind?2nd–6th grade · 2 days of testing · free🌦️ Growing and weather · 🌱 Outside and plants